US2517838A - Drying oil - Google Patents

Description

Aug. 8, 1950 1 R. A. CARLETON DRYING OIL Filed March 2, 1943 5 Sheets-Sheet 1 Aug. 8, 1950 R. A. CARLETON DRYING OIL 5 Sheets-Sheet 2 Filed March 2, 1943 alH h l l l lh l l l l l l l lwl l l I I I H Hu l l l l m l l r INVENTOR Aug. 8, 1950 R. A. CARLETON DRYING OIL 5 Sheets-Sheet 3 Filed March 2, 1943 INVENTOR 444 ail W14 Aug. 8, 1950 R. A. CARLETON DRYING OIL 5 Sheets-Sheet 4 Filed March 2, 1943 INVENTOR Aug. 8, 1950 R. A. CARLETON DRYING OIL 5 Sheets-Sheet 5 Filed March 2, 1943 14 WMM4%%' M W rn sq Patented Aug. 8, 1950 when i ,Y' lB i O Robert A; Carleton, Maniaroneck, 1.

This invention'relates c a-methodorprpduc ing drying oils of improved'drying' and film forrn-- ing properties, from drying oils {or non-conjugate type. v r H y invention primarily re ates to which are united by double bonds',by which treat ment new doublebonds are introduce'd and'rear l the carbon chain rangement" of. double bonds I c I c to give a conjugate rather than a non-conjugate structure is eitected. It is to of double bonds intodete rminate posmbns m the volves bothf an increasein t double bonds linking "partied bon atoms of the carbon chain, tioning of these carbonatonis in nsaturate re and in such nos bonds are in conjugate relation." My invention concerns itself known fact that in dryingbils, the rapidity with which they dry and the hardness ofthe film which they produce is affected not only by the which: saturation of the oil, or bonds which it contains the arrangementof the unsaturated lihltages 'or' I the oil mommies- It'is' well understood that e'ach dryingoil' isflco'rnposed double carbon bonds, in

of a varying number or"components-which;m

instances present great difir'ence's; inthe order of their unsaturation, and in-the arrangement or their double carbon bonds. L The above i'sto 'be' taken generally 'as referring toeachcommerci'al drying or semi-drying oil;

bean oil, etc., and'in its 'relation specifically 'to-the order of. unsaturation and the order otconjuga tion is to be taken also as relating'to 'the-individual components offthe oils, such as'thej g lyc'erides' of linoleic acid; and the glycerides of nn'pieme acid.

drying oil product which treatment to which it has beensubj'ected 'is com: posed in substantial entirety"'of"desired 'corn which is effected 2 and treatments in a-in'anner provement 'in' the'properties of the dr'yin'groil prod-- uct whichisrecoveredand in a mannertoobtain a treatment of non conjugate type glyceride oils-containing large amounts of glycei'id'es having 18 or m re; atoms in the'carb'on' chain, at 1easttwojpairs -of=v I be understood fur ther that my invention involves trfeintroductipir' carbon chain of the oil'inolecul'es; and that'i't in H thcafbonchain that approximately all the 'introduced double:

'with'the weir" umber of double-carbon" V but that thosedesirable propertiesof the drying on are arrested 'greatly by such as linseed oil; soya My invention concerns'itself alsowith a finished by virtue or the" total in dete'rminate order the a physical and chemical 1 changes giv'ing the desired product.

1 As is 'well-known,China-Wood oil maybe taken as exemplifying drying oils having most of their a; double bondsin conjugate relation, another and less known member of'the class being oiticicaoil.

While the total unsaturation of China-wood-oil, as represente'd by its iodine absorptionfindex, is

substantially less than the total unsaturation oi linseed oil or perilla 'oil'fChina-wood'oil dries much fmore' rapidly than the rnore u'i' saturate oils the unsaturated glycerides of 'whiehpresent as an average no substantial conjugation." Thus, China-wood oil is compes'ea arge1y' or the highly reactive glyceride of elostearicecid, in which substantially all the double 'Lbo'rids-"-present are in conjugate relation. As is'well k'nown, that oil polymerizes or gels at equal'temperatures many times faster than the more unsaturate but non-conjugate and relatively lessreactive linseed oil. As noted, there is substantial difference in the type of film formed by conjugate type oils and the non-conjugate type oils because the are" characterized by through drying to give hard and highly resistant coatings, whereas the films of'non conjugate oils dry from the surface, so that the underlying regions of the film dry slowly, andthe film does not have the hardness and resistance ofa film composed of the conjugate type "Itfis generally considered that the non-conjugate type glyc'erid'e oils owe their drying properties chiefly to their inclusion of unsaturate linoleic acid glyercides having two double carbon bonds inthe 9-10 and 12-13 positions and an iodine value of about glycerides having three double carbon bonds-in the 9-10, 12-13, and 15-16 positions, and an iodinevalueflof about 274.. In addition the oils containjglycerides of oleic acid and of saturate acids, having little or no drying power. The glyceride of oleic acid .has one double carbon bondin the-9-1O position, and has an iodine value do those'otherand non conjugateoils, and has the ability to form films conjugate oils form films which 181, and to linolenic acid,

As has been above indicated, the proportions of the several saturate and unsaturate fatty acid glycerides occur in the various oils in greatly varied proportions, to form mixed triglycerides. Certain oils, such as cotton seed oil and corn oil, while containing substantial amounts of linoleic acid glycerides, also contain a large proportion of saturate fatty acid glycerides and of oleic acid glyceride. These oils, of which I may take cotton seed oil and corn oil as exemplary, are not, therefore, commonly considered to be drying oils. These examples of such oils as have iodine values over 100, may be used alone or in mixtures as the starting oil for my process.

My present invention involves the discovery that by hydroxylating and then condensively dehydroxylating unsaturate non-conjugate glycerides of fatty acids there are introduced in the carbon chains of the oil molecules an increased number of double carbon bonds in determinate positions and in conjugate relation. I have discovered that this hydroxylation and attendant condensive dehydroxylation, with introduction of double carbon bonds in determinate conjugate relation may be effected selectively, to impart to the, oil increased tendency readily to polymerize which is of measured order.

Concretely I have discovered that the reactivity of fatty acid glycerides having 18 or more carbon atoms and two or more double bondlinkages in the carbon chain may be greatly increased by hydroxylation followed by condensive dehydroxylation to introduce new double carbon bonds and to increase conjugation in the carbon chains of the oil molecules, and that the hydroxylation and consequently the dehydroxylation may be selective as to the number and positions of-theunsaturate carbon atoms which are, involved. This involves the further discovery that the determinate positions in which dehydroxylation based upon precedent hydroxylation is effected in drying oils of that type are such as to give maxi: mum effectiveness. inincreased reactivity to the increased unsaturation and the conjugation which has been introduced.

The hydroxylgroup addition to the unsaturate carbon atoms, which comprises the first step in my novel process, is effected by reaction of the oil with oxygen inthe presence. of Water, and any suitable and convenient reagentsand procedure for so doing may be employed.

In exploring the mechanism, I have found that epoxide formation and hydroxyl. addition to the unsaturate carbon atoms in the glyceride molecules may be accomplished in various ways. One manner of accomplishing this is totreat the starting oil with air or other oxygen-containing gas, with or without the use of oxidation catalysts, and effecting the hydroxylation predicated upon epoxide formation by conducting'the oxidation procedure in thepresence of steam or water, so that cpcxide formation is accompanied-imme diately by hydration. Another procedure, by; which hydroxyl addition is accomplished -is.;.b'y, treating the oil withwater solutions of compounds Which readily give up oxygen, such for ex e a ot sium rm n an t i" hy r e peroxide. A still further example of procedure for effecting hydroxyl addition 'at unsaturate carbon atoms of the glycerides is to effect epoxide formation immediately resulting in hydroxylation, by reacting and decomposing a Water solution of oxygen-containing compounds such as sodium carbonate with a reagent therefor such as gaseous chlorine, with subsequent liberation of free oxygen, which reacts with the unsaturate carbon atoms'present to add hydroxyl groups thereto. It is possible also to combine these procedures as by treating the oil with air and with a water solution of an oxygenating compounds, such as potassium permanganate.

The above recited procedures are to be taken as illustrative of treatment by which the fact of hydroxylation in the oil molecules may be attained, and not as limitations upon my invention. It is to be understood that hydroxylation of itself serves to decrease rather than to increase the unsaturation and reactivity of the oil. When, however, the hydroxylation is associated or combined with condensive dehydroxylation a marked increase in unsaturation and reactivity of the treated over the untreated oil is accomplished.

-ll ehydroxylation is effected by condensation between the added hydroxyl groups and hydrogen atoms of the original molecular structure under the influence of heat and preferably also with acondensivedehydroxylation catalyst and under substantially. anhydrous conditions. Assuming that dehydroxylation is effectively performed, the increased, unsaturation and the conjunction effected in the glycerides of the oils depends upon the order of hydroxylation which has been effected in them. Consequently, the order in which unsaturation is increased and conjugation created in the treated; glycerides is controllable by seleetivity in the precedent hydroxylation.

Selectivity in the treatment of. the. oil to. increase its unsaturation and conjugation is an important consideration. If we consider linseed oil as-thestarting material for my treatment, it has been above noted that the composition of such oil is approximately 24% linolenic acid glyceride, 62% linoleic acid glyceride, 5% oleic acidglyceride, and 9% saturate acid glycerides. Linoleic acid has in its carbon chain two double carbon bondsin the 9-10 and 12-13 positions. If then we consider that the acid is completely hydrpxylated to form tetrahydroxystearic acid and then issubjectedto condensive dehydroxylation, four, ofthe original atoms of hydrogen are removed from the molecule and four conjugated double carbon bonds are introduced in the 7-8, 9-10, 11-12, and 13-14 positions, Similarly linolenicacid has in its carbon chain double bonds in the 9-10, 12-13, and 15-16 positions. When there is complete hydroxyl group addition to form hexahydroxystearic acid, followed by condensive dehydroxylation, the result is to remove six of the. original hydrogen atoms and to introduce double bonds in the 6-7, 8-9, 10-11, 12-13, 14-15, and l6. l 7.positions. Mechanismof a condensive dehydroxylation reaction is rather complex, and not completely understood. In view, however, of theresultsattained, it is quite probable that due to. strains setup in the molecule by the relatively high reacting temperature and atomic recombinations, there. is first'a migration of the relatively mobile hydrogen atoms with resultingshift in position of the active carbon atoms, to permit condensation between the added hydroxyl group and an adjacent hydrogen atom to form the above indicateddouble bond arrangement, without substantial formation of objectionable ring compounds.

-I- have found that because of an inherent selectivity, orv difference in the degree of reactivity toward epoxidation exhibited by the several unsaturate carbon atomsin the oil molecule, depending upon. their relative. position in the carbonchain, and by the quantitive and selective regulation of the variables affecting the hydroxyl group addition to the unsaturated carbon: atoms, the startingoil may be treated by the present invention to have a lesser or greater determinate degree of unsaturation and conjugation with consequent variation in its heat-reactivity within the aforesaid range. It may be here noted that the position of the unsaturate' carbon atoms in the molecules of a drying oil has a great influence on the reactivity of the oil; Unsaturation, and more particularly conjugate unsaturation, tends more greatly to heat reactivity and oxygenreactivity of the oil the closer it is to 'the glycerol radical of the oil molecule. It is animportant aspect of my process, as will hereinafter appear more specifically, that in it unsaturation, and unsaturation in conjugate relation, is introduced directly and permanently in determinate positions and that such positions are favorable to high reactivity of the product oil.

The initial factor in my process is the' ability of unsaturate carbon atoms to react-additively with oxygen to form epoxide, which in the presence of water immediately hydrates to form' a hydroxyl group addition. I have foundfurther that when two or more pairs of such carbon atoms are present the position of the carbon atoms solihked in the carbon. chain greatly influence's'their relative reactivity with oxygen. Thus if linoleic acid glyceride be considered, the carbon atoms inthe 9-10 position require greater stimulus to cause their reaction with oxygen than is required by the carbon atoms in the. 1213"-positi0n. In linolenic acid glyceride the carbon atoms in the 15-16 position in like manner have greater reactivity than the carbon atoms inthe 9-10 position, and they in turn have greater reactivity with oxygen than the carbon atoms in the 12-13 position.

individual operation, the intent to effect selec-.

tivity-being present and procedural guides of general sort being had. The quantity of oxygen which may be rendered available from the oxygen-supplying substance used in the process may be taken as theprimary guide with respect to the desired theoretical epoxide formation and hydroxyl addition to the. oil molecule. The supply of water and its contact with the oil involved in hydroxylation should be ample to effect substantially complete and immediate hydration of the epoxide addition. The efliciency of. the procedure by which epoxide formation is effected may then be considered,'and thisiinvolves as variables the activity of the oxygen-supplying reagent, the time-temperature and pressure factors, the quantity and efiectiveness =of the oxidation catalyst if such catalyst be'used, and the effectiveness of contact between the oil molecules and the source of oxygen.

In all the important non-conjugate drying andsemi-drying oils the preponderant fatty acid glycerides are the linoleic'acid glyceride having 18 carbon atoms and two points of unsaturation in its carbon chain and linolenic acid glyceride having 18 carbon atoms and three points of unsaturation in its carbon chain. It may be stated broadly that the response of any starting oil, or mixture of starting oils, to my process corresponds closely to the quantity of unsaturates of that sort which it contains. in the practice of my invention it istherefor'e' a simple matter to adjust'the'variables ;in con-.-,;

The exercise of selectivity in the hydroxylation.

In obtaining selectivity 6 oil.

to stimulate'the mechanism by. which epoxidation occurs and' the hydroxyl groups are added to: When it is'deemed expedient the carbon atoms. to accelerate theactivityof the oxygen-supplying medium in effecting hydroxylation, epoxidation may be promotedby adding to the oil subjected to treatment a suitable quantity of well-known oxidation catalysts including the compounds of oxidizing'metals used'as dryers in coating compositions.

Good oil-oxygen contact is important from the view point of selectivity and from the view point of obtaining the desired orderof treatment in the entire volume of oil treated: If highoiloxygen contact efficiency is obtained, regulation of the other variables of the process to obtain approximate uniformity" and selectivity .in -thechanges appearingin'the product oil is facilitated.

Thus if the contact factor approaches maximum eihciency, the time of treatment'is shortened, and the quantity of oxygen rendered available in reaction with the oil approaches closer to the quantity supplied'by the oxygen-containing reagent in effecting the desired theoretical epoxide-formation and hydroxylation.

and such checking is facilitated ina continuous operation in which 'fully treated samples re-.

peatedly may be taken, in which there is substantialuniformity throughoutthe body of the oil being treated, and in which the variables are particularly well under control. Thus thedecrease in unsaturation caused by the hydroxylation may be determined by well-known and usual tests for change in iodine and hydroxyl. value. By observing the results of such tests appropriate changes in the variablesv involved in the hydroxylation procedure may be'made to deliver for condensive dehydroxylation'oil which-has been hydroxylated to the extent desired. I

The subsequent step of condensive dehydrogenation, which as is well-known involves the removal of a hydrogen atom from the oil molecule to combine with a hydroxyl group to form water, is effected primarily by heat. This is'illustrated by prior practice-in the dehydration of castor oil in which one hydroxyl group initially ispresent; 1 I

The time-temperature variable in thecondensive dehydroxylation quite commonly is decreased by the use of a dehydrating catalyst. 'A typical activating dehydration treatment for castor oil is to hold the oil at a temperature of about 400.F. to 500 F. for 2 to 3 hours, using a substantial quantity up to .4% or .5% the weight of .the oil of a suitable dehydrating catalyst, such as the salt of a non-oxidizing acid. Dehydrated castor oil is, however, much less heat-reactive than my product oils. Thus China-wood oil under standard gelatin test condition usually polymerizes to as ubstantially dry gel in 10 to 12 minutes at aformity with altered compositionsof the starting.

in my process it is notnecessar y catalytically 2; @117; see

7 stantially dry gel.in.3i to: 5. minutes at atemperature of 600 F.

The condensive: dehydroxylation stage of my process thus-presents a. problem which is. not met in the treatmentof castor oil. Because of the high' heatireactivity of the oil' which is subjected successively to hydroxylationv andv to condensive dehydroxyla'tion in accordance with my invention, there is a tendency for the oil strongly to polymerize immediately upon dehydration. If then this stage of the process be carried on in a .relatively large mass: of the oil, thedehydrated oil tends rapidly to polymerize and to pass to a stageof high voscosity or gelation. before it can be cooled belowits polymerization temperature.

I employ a..flash dehydration procedure, by

whiclr the hydroxylatedi oil is condensively' dehydrated with: relatively slight increase in its viscosity. Desirably such flash dehydration is so conductedthat water from the reaction is removed from'the. oil substantially as it is formed,

and it dependsv primarily upon. raising the oil very. rapidly,.in substantially less than one minute, to a temperature much higher than commonly employed in dehydrating castor oil, for example, a temperature of from about 500 F. to 700 F. and. even higher, and upon substantial completion of the reaction immediately cooling the oil. below its active polymerization temperature:. In such procedurethe oil is so presented for heating, as in a thin film, that its heat-absorption is very rapid. and the oil moves rapidly through the zone in which it is treated.

Exemplary apparatus in which the method of my invention in itsvariant embodiments may be practiced is shown inthe accompanying drawings, it being understood that the apparatus herein shown is illustrative only of many forms and types of apparatus which conceivably may be employed while conforming to the method of my invention.

In the drawings:

Fig. Ia is a diagrammatic view showing one Fig. II is a cross-sectional view through the hydroxylation reactor shown in Fig; Ia taken in the plane of the section line II-II of Fig. Ia, and showing in detail one of the elements of, the said hydroxylation reactor which are organized to provide contact between the oil subjected to treatment and the reagent, or reagents, with which it is treated.

Fig. III is a vertical sectional View through the contact element of Fig. II taken in the plane of the section line III-'-III of Fig. II.

Fig. IV is a fragmentary vertical sectional detail view taken through the upper region of the dehydration reactor shown in r Ib, the portion of the reactor shown being embraced by the bracket line IV-IV ofv Fig. Ib.

Fig. V'is a fragmentary vertical sectional detail View taken through the dehydration reactor of Fig. Ib in a region intermediate the height of the reactor, and embraced by the bracket line V'-V of Fi lb.

Fig. VIis a fragmentary vertical sectional detail view taken through the lower region of the dehydration reactor shown in Fig. Ib, embraced by the bracketline VIVI of Fig. lb, and showing connections to the lower region of the dehydration reactor.

Fig. VII is a diagrammatic view of modified hydroxylat-ion apparatus, which maybe. utilized in place ct -the apparatus shown-in Fig. Ia in operative: association with suitable dehydrogenation apparatus, such suitable, dehydrogenation apparatus being: exemplified: by that shown in- Fig.1!) of the: drawings.

Referring initially to-Fig. Ia and to Figs. II and III: of the" drawings; reference numeral I designates'arr; oil. feed pump which, by way of inlet connection: 2. supplies oil for treatment to hydroxylatingtreactor' 3. A pump 4 supplieswater, which: may be if desired a reactive water solution, and which preferably is. mildly alkaline, to the reactor 3zby way ofan. inlet. 5.

Primarilyconsidered, reactor 3ris a cylindrical.

columnar: vessel which preferably is constructed of metal resistant. to; the corrosive action'of the materials: contained by it during the progress of the reaction, and isof.- suitable: cross-sectional area and height. to maintain continuously flowing streams of oil undergoing treatment and treating reagents: for the oil at suitable reaction. temperatures, for suitable periods of time to effect the:desiredhydroxylation of the oil'. R'eactor 3- is provided. with a plurality of contact, or

reaction, trays 6' arranged. at spaced intervals.

through'outits height and purposed' to effect intimate contactibetween the oil: subjected to treatment and the reagent, or reagents, with which it is treated;

Reaction" trays 65, as is: shown in detail in. Figs. II and IIIv of. the drawings; comprise each an upper plate i and a lower: plate 8, spaced apart to forma temperature controlling jacket space 9, provided with inlet. connections litand outlet connections H, for: the supply; of heating and cooling medium, and. with circulationedirecting baflles l2. A.plurality of bubble caps I3, which are preferably as shown of rectangular type, and which have closely spaced narrow slots M adjacent their loweredges', are supported a suitable distance above plate 1 and enclose the discharge ends of. vapor ducts 15, the lower portions of which pass in-vapor tight manner through jacket spaces 9, and which have their. upper openings I 6 in discharge relation with the upper regions of the: chambers within the bubble caps I3; Interconnection, or down, pipes ll" provide for the flow of liquid from the trays 5 to successive lower trays of? the system; 'Ifhese down pipes I'l' have their upper: intake ends it outside the bubble caps of" the several? trays with which they are associated, and positioned a suitable height above the plate l? of each of the trays, to maintain a determinate: depth; of' the liquid flowing over the trays; Thelower outlet ends It of the down pipes I? are sealed'iagainst vapor fiow by submergence an adequate distance in. the liquid of the tray 6 lying next. below" the tray from which they provide'overflowconnection.

Speaking'in' terms of' my method, continuously flowing streamsof. oil subjected to treatment and oxidizing and hydrating reagents introduced re spectively by way of inlets 2 and 5 are supplied tothe uppermost of the reaction trays 6 by supply connections 20 and 2!, which discharge immediately above the upper surface l of the uppermost trays t, at the space 22 outside bubble caps rs.

This oil surrounds and moves between bubble caps l3 in a sinuous manner, being drawn oif by way'of down pipe I"! at a level which is a suitable height, such asabout 1%", above plate I. In accordance with usual procedure, the inlet E8 of down pipe: [1' is: remote from the openings of supply. connections oxidizing agent, additional 'tinuously, part being drawn by way of connection 20 and 2 l thus tocause movement of the oil past the several bubble caps l3 of the tray. In each of the underlying trays, the discharge end of down pipe I! leading from the tray next above takes the place ofsupply connections 20 and 2|, but otherwise the arrangement is identical. hhhh A The oil subjected to treatmentthuspasses progressively downward through the reactor, and. in its passage encounters an upwardly rising gaseous oxygen-containing medium, preferably air, which is preheated to a suitable determinate hydroxylating reaction temperature, such as a temperature from about 130 F. to 250 F., and which is supplied at a rate suitable for eiiecting hydroxylation in desired order. I

Such gaseous oxygen-containing I medium, which will be hereinafter spoken of illustratively as air, enters space 24 in reactor 3, at inlet 23, and passes by way of vapor ducts I5 into bubble caps 13, from which it issues into the surround- .ing oil on the several plates 1, in the form of finely-divided bubbles, by way of slots I4 in,the bubble caps. The air thus intimately contacts and agitates the stream of oil passing over the several reaction trays 6, and intimately, mixes with the oil in reactive contact therewith. The residual air separating from the oil in the uppermost reaction tray 6 passes from the reactor by way of vapor discharge connection 25.

The air thus brought into contact with the oil streams passin over trays'fi serves the dual purpose of agitating the oil and mixing it with any to the air, which may be used in this step of the process, and also supplies oxygen for reaction at unsaturatecarbon atoms of the oil, to effect epoxide addition thereto. In this connection, it should be explained .that the water supplied at inlet 5, which may be merely mildly alkaline or may be a, solution of a suitable reagent or catalyst, mixes with theoil in the uppermost of the trays 6, and passing with the oil to successively lower trays in the series throughout the height of the reactor, is maintained in a condition of intimate admixture with the oil by the agitation. provided by .the air streams which are passed therethrough. This water is, as has been explained, necessary to form hydroxyl group additions by hydration at the points of epoxide formation. After passing over successive trays 6, the oil and water are discharged by a final down pipe 26-to region 21 at the base of the reactor 3, where-it separates .into a lower aqueous body and an upper body of oil. An oil-water interface level regulator 28 of usual construction is provided, and operates in association with pump 4, and pump-flow regulator valve 29, to draw off the aqueous layer from chamber "21 and thus to maintain an approximately constant level of the oil-water interface 30. I is in part recycled conofi by way of connection 31 and a fresh'supply being introduced 32 under the influence of pump 4. This is of importance, if the water con- The water desirably tent be associated with a suitable oxygen-supplying reagent, such for example as potassium permanganate or hydrogen peroxide, because it provides for the addition of fresh solution of appropriate concentration without wholly drawing oil the solution which has passed through the reactor. If so desired, however all the used aqueous solution may be withdrawn and fresh solution supplied. As water is drawn off byway; oi-draw-off connection 3|, pump 4 maintains the :valve 3.6.,- to the lower. tray.

pres ure; u stant l entrainmentby-way; of 'vapor outlet 25.

"The preferred temperature. at which .the .hy-

droxylation iseffectedwilldepend upon the kind and condition of vthe. oil, andother operating variablesp but in generalthe reacting temperature is -ashighas; may beLused without effecting substantial epoxide::de'Compositiomand @the formation .Df: fiXBda'OXi-dfiti-OH products. in the oil. As above noted the preferred temperatures for hydroxylation lies within the approximate range of. 130. .to 250%Etu-The oil may be subjected to difierent-rates orvintensity ofireaction as it progresses through the reactor,- .by maintaining the oilwhile passing-over. different pairs of reacting .=:trays, or; different:individual-trays, at determinate difieren-t ;temperatures.--.

Theetemperaturezicontrol :i the apparatus is obtainablezbyzsupplying, a temperature regulating ifiuid to thejacket spaces :9 in eachof the reaction .traysxfil-uAsshown,sthese jacket spaces are in communication .witha source of; heating fluid, isuch as'jhot waterior, steam, asiby way of connecl".ion*.3,4,--.and.with aisource of cooling water as by way of;connection-35uziJThe supply of both such temperature controlling mediais under the con- -.trol of a temperatureregulating valve 35, having a heat-sensitive. element l -31 subjectedto the in 'fluen-ce of :the temperature .of material flowing over the: aerating, .or' reaction, trays. As shown, -the u-traysiare connected in pairs, heating and coolingimediabeing supplied byway of regulating of each'pair of branch inlet connectio lfim andyto the jacket space of the traynext-above by waysof connection If). 0b-

-viously th e temperature regulating means may be,,modifieduindependently: to regulate the term peraturein each such tray. Branch outlet connectionsll, I; lead fromjthe upper memberv of each ;.pair. rpf-,.trays -'to alcommion discharge line I la for heatingandcoolingufiuidsw v a.

v By connection, .Qf. such; sort, heating. or cooling iluidis: supplieduto maintain each-region of the reactor; 3 at the desiredtemperature to which -the ,..automati;cgycontrol, organization is set, or

which itisconstrncted tomaintain. ,It may here be noted thatthej epox1dation reaction is strongly exothermic.-. v

. PIBSSHITBfWithi- -the reactorfmay, if desired, be

icontrol led,byj comniunicatioii with sources of supe tm spheri and :su atmospher c p ssur In'the event water one. water solution of an oxidizing reagent isomittedand steamis supplied by wayof; steaminletconnection20B and. utilized as the sole; hydrating; ;means, the interior of reactor ;3 is preferably maintained at a suitable reduced ,to avoid condensation of @thest a y- Efor sxamp ei wh n ef c g h droxylating reaction to;the-o i1 atv a temperature .qtg E. ,with the use oi steam, thereactor woulderably b ma nt in any Suitable 1'neans,- -at; a press ure of about 20. inches of mer- ZG TX-w 3 191 oth r; nh r pr s in ma circumstances, superatmoa be ,usedto increasethe soluhydrating-mediumin the oilv bil ty; m se an ")1; -;have:difsco,vere d that the use of steam tends ,to renderv the-operation .of the hydroxylation reaction more selective'with respect to the points of unsaturation in the molecule whichare attacked. This is apparent from consideration of the man-' ner}'in .which theoil undergoing treatment is handled in, the apparatus, -The oil while passing in a sinuous manner over the several reaction trays astasee ofa typicalccommercialaisize apparatus? described is progressively suhjecteds'toithe influence of and intimatelyccontactedby every great number of jets. of airissuingfronrtheclosing spaced slotson thelower edges ot the: bubblemaps Thus, the. eifect. in the. apparatusdsrepeatedly: to; mix the oxygen-supplying and? hydrating media with the oil stream in the severak reactionatraysofzthe apparatus. Such mixture. is; made; as; has been shown, in a manner-:torefiecteaihigh order-offintimacy. The; is in..f.ormi ofibubbles; although the bubblestarevery small; and the water, which may hold in solutiomaxr additionaltoxygem supplying orcatalyzing: reagentis: mixed. intimately with the oilin dropletaofrsmall; dimension by the actionof theair;

The eiiectiveness: of. the;v procedure thus depends upon therepetltiveitreatment;oiffthe oiliin the several reaction: trays; over which'i-t successively passes. limited proportion, of the. oil. molecules effectively into contact with available oxygen: atoms and water molecules in eachrzone or treatment. during the progress of" the oil throughthereactor, is. effective. because the. oil. in-zrelatively" small volumn is repeatedly: subjected to hydroxylating media under hydroxylatingconditions; My preferred practice, insofar asthis apparatusflisiconcerned, is to conduct; the process: to eflect throughout the body ofthezoil at least'substantially complete hydroxylatlon of" the double bonds at the 1'2 -13 -position= inthe molecules of linoleic acid glycerid'e and at-the 15' -1'6"position in the molecules of linolenic acid glycerlde.

It is not difii'cult toconductthehydroxylation step inapparatus of'this: sortiin a-manner toobtain the result above indicated; because the tendency so to function'is inherent. A primerequisite is that the water-"supply be adequate, with respect toefiiciency, fully to hydrate the epoxide addition as it is made; Thus the temperature being within the approximate range of about 130 F. to 250 F., in the:presencexof-"an:abundance of water, it is possible-Ito hydroxylatethe-unsaturate carbon atoms ofthe-oil moleculesapproximately to the maximum ,extentawithout substantial formation of permanent oxidation-or objectionable rin compounds. If in beginning a run, samples show an undueproportion affixed oxidation products, the volume of watersupplied is increased, and if the-condition persists the temperature is reduced toadegree-sufii'cient'to avoid such contamination; In the apparatus under consideration, the preferred time of treatinent depends upon the-rate at which the oil is supplied. This will, of course, vary withspecific'apparatus designs, individual oil, and the-other" conditions of the process. A preferred procedure-is to test a sample for its order-ofhydroxylation soon after the beginningof a run and'accord'ingly'toadjust the several" operatingvariables;

The oil which hasbeen subjected to the-bydroxylating treatment. and which lies as an upper layer on thewater-in the baseofythereactori; is continuously withdrawn at anadjusted rate' of discharge by-means ofa' pump 38-, and an; oil level controller 39, operable by way" of pumpflow regulating valve 40" to maintain the upper surface of the oil in the base of 'thereactor'at an approximately constant'level.

Desira-bly; drawofl line 41; which leadsfr'om'the interior of the reactor-3 to-the pump-38% is provided with a valved drawofi'connection'll aby which test'samplesreadily may be taken oft from time to time.

Suchtreatment, whichrbrings a Oil drawn ofi by pump 38 is delivered to apparatuszfor conducting the second, or dehydrating, step of the process by way of supply line 42. Desirably, supply line 42 passes by way of an oil heater 43: and de-aerator 44, in order to remove fromv the oil any entrained or dissolved air, loosely-bound oxygen, or moisture, which would cause-excessive foaming and promote the formationof undesired compounds in the dehydroxylation treatment. Thus, oil passing by way of supply'line 42 is firstheated, as in the heater 43, and isthen delivered to tie-aerating vessel 44, which is maintained under suitably reduced pressure, by which. entrained or dissolved air and moisture are removed in the form of vapor by way of vapor outlet connection 45. The reach of the discharge-line 42-1eading from de-aerator 44 is provided with a pump 46 leading by way of connection 41:, to a-heat-exchanging element 43in condensi-ve dehydroxylation reactor 50. From heatexchanging structure 43, supply line 49 leads through other preparatory apparatus elements to inlet 51- adjacent the top of the reactor.

The-preparatoryapparatus elements, as shown, comprise a catalyst-mixing chamber 52, in which the oil is intimately mixed with suitable condensi-ve dehydration and hydrolysis-promoting catalysts from a supply tank 53, and proportioning catalyst-feed device 54 of common construction. As shown, catalyst supply tank 53 is provided" with agitating means 53a by which the catalyst may be mixed-with a small portion of oil, which-desirably is identical with the main body of-"oil subjected to treatment. Between catalyst mixer 52 and inlet connection 51, supply line 49 leads-through an oil heater 55in which the flowing'stream ofoil is brought initially to a temperature which at least approximates that of the condensive dehydration reaction towhich it is to be subjected.

Condensivedehydroxylation reactor 50 desirably is constructed throughout of a metal capable of resisting thecorrosive action of the materials introduced into-it or produced in conducting the process; Its shell is a cylindrical columnar body of adequate cross-sectional area to provide for thesevera-l effects to be created in it, and is of a height adequate to provide a relatively great length of travel of oil passed downwardly through it and subjected to the condensation reaction in' its-passage. Within reactor 50 and of a length approximating the height of the reactor shell, there is -a tubular element divided vertically'intoan upper heated: reaction section 56, anda lower cooling section 51, which forms part of-the-heat-exchanger 48, by which the incoming oil isheated and by which the temperature ofoil' treated in the reactor is rapidly lowered.

Pre-heated' oil entering reactor 50 by way of inlet connection 51-, is first received by a separatingvaporizer 58; in which any fatty acids, or other volatiles which may be carried by the heated oil flash-vaporize under the pressure conditions existing interiorly of the reactor, and pass by way of vapor outlet 59-to suitable condensing and collecting-meansnot shown. It may be explained thatthe-interior of reactor 50 surrounding the tubular structure 56-: and 51, desirably is maintainedata reduced" pressure, for example under a pressure of Ste 5 mm. of mercury, by suitable vacuum-creating. means, not shown. The oil in substantially liquid'form passes from vaporizer 58 by way of a connection 60, to an oil distributor Glatth'etopof' reactortube 56; from which it is passedoutwardly'by way of. a number of narrow,

or for storage.

. be about .065" and even less in thickness. The

oil film travels downwardly over reactor tube 56 rapidly under gravity, as for example, at a speed of to lineal feet per second, the speed at which the oil in such fllm travels depending somewhat upon the viscosity of the oil and the effect of vapor formed by the reactions which take place in the oil film.

Any suitable agency such as hot vapors, hot circulatin fluids, or electricity for heating reactor tube 56 to the relatively high temperature required for the flash condensive reaction may be used, preferred heating means being shown in Fig. lb and in Figs. IV and V of the drawings. As shown therein, reactor tube 56 is electrically heated by means of electric current which is supplied by way of transformer 63 and electrical connections 64, 64a. Transformer 63 receives current from a line 65 leading to any suitable current source, by way of automatic control switch 66, operable under the influence of a thermostatic regulator 61 and which has electrical connections 60 to transformer 63 and connection 69 with a thermocouple 10, which lastnamed element extends through the reactor shell into operative relation with the heated surface of reactor tube 56.

Electrical connection [4 between low-resistance tube H and high-resistance tube 15, together with its insulator, is engaged in a liquidtight partition l6 arranged at the junction between heated reactor tube 56 and lower cooling tube 51. c I

The film of oil, passing rapidly down the surface of reaction tube 56 is raised quickly to a relatively high reaction temperature lying within the approximate range of 500 F. to 700 F., such as a temperature of about 550 F; and continuing downwardly over the surface of cooling tube 51, still in the form of a thin, rapidly flowing stream, is cooled quickly to a temperature below that which would produce in it substantial heat polymerization. For example, it is rapidly cooled to a temperature of about 275 F., or lower, by heat exchange with the cooler stream of oil flowing upwardly in annular'space 81 in direct contact with the inner surface of cooling tube 51. The treated oil thus cooled collects in space 89 at the base of the dehydroxylation reactor, and is continuously delivered from it by way of a discharge connection 90 for further treatment,

I have found that there is a substantial difference in the temperature at which the hydroxyl groups in difierent positions in the carbon chain react or condense with adjacent hydrogen atoms, the hydroxyl groups at the remote carbon position reacting at a substantially lower temperature than those groups nearer the glycerol group in the oil molecule. This difference in reaction temperature is quite substantial, and may amount to as much as 50 F. or more. While flash dehydration is desired, if the condensive reaction should take place instantaneously throughout all regions of each of the hydroxylated oil molecules, upon contact in the upper region of the reactor tube, the immediate evolution of substantial amounts of water produced by the condensive reaction would result in violent ebullition and oil might thus be thrown mechanically flOmthe'surface of the reaction tube.

In my condensive dehydroxylation step, the condensation reaction is in effect a flash reaction, inasmuch as it usually takes place within asperiod of a fewv seconds, at a temperature of from about 500 F-. to 700 F., rather than in a period in the order of three to four hours at temperatures from about 450 F. to 540 F., when condensive dehydroxylation is conducted in ac: cordance with a batch procedure. That is, in the progress of a thin film of the oil downwardly on. the surface of, a reactor, such as the surface of the. reactor tube 56 of the dehydroxylation apparatus shown, the oil is subjected to condensive reaction-temperatures so high that dehydroxylation is :substantiallyacompletebefore it is cooled,

as by passing over the cooling surface, such as is provided by the cooling tube 51 of the apparatus shown. As indicated above, it is desirable, however, that the-tcondensive flash reaction should not .be so wholly instantaneous as to produce violent mechanical effects in the film of oil sub- .iected to treatment. Thus, I preferto supply 011 which has been pre-heated, as by its use in heatexchange and subsequent heating in an oil heater, to a temperature which is at least 50 below the maximum temperatureto which it is to be brought in the reactor. For example, Iprefer to supply the oil at a temperature no higher than from about 450 F. to 500 F., and to bring it during its brief period of contact with the re actortube to its maximum, or flash, reaction temperatureof at least 500 F., so that the zone of the condensive reaction comprises substantially theentire length of reaction tube 56.

.Bythe term fflash condensive dehydration, I mean a condensive dehydroxylation reaction in which the oil is subjected for a very short period notsubstantially exceeding 1 minute to elevated temperature from about 500 F. upward and below a temperature at which heat-decomposition of the ,oil will take place during the period of the treatment. I have found that such flash dehydration should be performed upon an attentuate body of the hydroxylated oil, such as the thin, circular stream, or film, of oil which the condensive dehydroxylator above described is organized to present.

The rapid cooling should in each instance bring the oil to a temperature below that at which the viscosity of the specific dehydrated oil is substantially increased by heat reaction.

By operating under subatmospheric pressure, as by maintaining a pressure of 5 mm. of mercury or less within the reactor, the flowing stream, or film; of reacting oil is maintained in substantially anhydrous condition by the continuous removalof water produced by the condensive reaction substantially as it is formed. The prompt removal of the water evolved by the condensive reaction from the flowing film of oil and the use of relatively high reacting temperature, provide conditions under which the rate and the extent of the dehydrating reaction may approach the maximum. Water being an end product of the reaction, tends strongly to inhibit its progress. Instantaneous removalof water, and the presentation of the oil in a thin stream, or film, greatly accelerates the condensive reaction at the temperatures to which the oil is subjected. Because of the very brief period of time during which the oil is subjected to high temperature ineffecting the condensation reaction, such high temperature may be utilized Without higher temperatures within the given range, the

use of condensive dehydrating-promoting catalysts is not important, and-that in the treatment of many oils the condensive dehydroxylation may be completed to anadequate degree in the substantial absence of such catalysts.

It may be stated that my flashdehydrating effects approximately complete dehydroxylation with the production of ancil having the desired high order of conjugate unsaturation, without involvin as an incident to such reactionheatpolymerization of the oil, which the further treatment to which the oil is subjected or the use to which the oil is to be put might render objectionable.

An exemplary form of hydroxylation reactor purposed particularly for highly selective hydroxylation oi the oil, is shown in Fig. VII of the drawings. This reactor, the shell of which is I'iesignated by reference numeral 95,.re'ceives oil for treatment through line 96 underthe influence of feed pump 9-1, and by way of flow indicator 98, and oil heater 99. Oxygen-supplying gas, for example air, is supplied in suitable quantity and under suitable pressure by means of air blower I00, flow indicator IIlI, air heater I02, and by way of line I63, to theinterior' of reactor shell 95. Steam, or hot water, is supplied byway of connection I04, and flow indicator I to'a'irsteam mixer I06 in suitable quantity to efiect hydroxylation of the epoxide addition formed by reaction between unsaturate carbon atoms in the oil and oxygen supplied by the" air. Both oil supply line 96' and air-steam supply line I03 connect with an atomizer IB 'Lby which the oil is discharged'into the interior of the reactor in the form of a fine mist, or spray, intimately commingled with the oxygen-supplying gas, and with the hydrating medium, such as steam or water vapor. By thus eiiecting highly intimate'an'd immediate contact between the'oil and'the oxidizing and hydrating media, there is asub'stantially instantaneous reaction, or sequence of reactions, by which hydroxylation' of highly selective sort is effected.

Desirabl-y, the mixture of air and'steam is supplied to atomizing device I07! at" a suitable hydroxylation temperature within the range above noted, such as atemperature of 175 F., and desirably, the oil for" treatment-is supplied to the atomizer at a similar temperature. this purpose, oil heater 99 isprovided with a heating medium, such as steam, by wayof a connection99a, supplied under the control of a temperature regulator 99b. Similarly, air heater I 02 desirably is supplied with pre-heating' steam by way of a connection I020, under-the control of a temperature regulator I021): Assuming, for example, that oil issupplied to the-reactor at a rate of 1000 lbs. per hour, I have found an air supply of 225 cubic feet per. minute. adequate to effect epoxide addition to selected unsaturated carbon atoms in the oil molecule without substantial formation of fixed oxidation compounds therein, providing that the steam, or other source of hydrating water at-a desirably high temperature, is also supplied in a quantity sufiicientinstantaneously to hydrate and thus-t0 make hydroxyl addition to the unsaturate carbon atoms as epoxide formation is efiectecb If'it is-desired For '16 to ac'cel'erate': epoxid'e formation, and consequent- 1y to. accelerate hydroxylation, a minute amount or suitable oxidation-promoting catalyst,

such for example as av compound of cobalt or the likei prefera'bly in oil soluble form, may be supplied-with the oil. Preferably the reaction chamber-' is maintained ata suitably reduced pressure,.such as a pressure of from 20 to 25 in. of: mercury; in order to prevent condensation of the hydrating'steama -Reduced pressure has another advantage in that because of expansion the volume of the air is greater than at atmosphere pressure, thus. providing greater contact eidciency between the oxidizing air and hydrating steam-and the minutely divided oil particles in the form of mistproduccd by the atomizer.

Briefly to consider the organization of the hydroxylation reactor, an inner shell Hi8, concentric with the outer shell 95, desirably is supported withinthe reactor shell by means of spiders to provide an annular space III], for the-escape of: unreacted air and other vapors irom tne reactor-by way of vapor outlet I I I. An oil level control device I I2 is connected in the lowersregion'of the reactor, and is operable by \vay'of an oil discharge pump I I3, and flow regulating-valve H 5, to maintain the oil within the reactor ata substantiallyconstant level. Because epoxide'for-rnation is a-reaction which is highly exothermic, cooling coil I I5 desirably is provided to establish heat-abstracting conditions in the interior of the reactor.

In operation, the fine oil particles under the influence of gravity and because of the velocity imparted to them'by atomizer I07, fall to the lower part of the reactor. ated oil is retained for a sufficient period of time under the influence of oil level control deice 5 I2 to effect gravity separation between the oil and any water which may be mixed with it. The oil from the oil stratum H6 is constantly removed by means of pump II3, and passes by way of discharge line 32a to the dehydrogenating reactor. Separated water is drawn oil by valved connection I I? to maintain an approximately constant. level of the oil-water interface.

Excess and oxygen-depleted air, together with steam and any other vaporous products of the reaction, escape by way of annular space III! to vapor outlet II I, passing on their way through oil entrainment separating louvres I I8 which act substantially to remove entrained oil particles from the discharged vapors. It is to be understood that oil passing by way of line 42a to the condensive dehydrogenation reactor 50 as with the form of hydroxylating apparatus previously discussed, desirably passes through a similar oil heater and de-aerator to remove any entrained or dissolved air, loosely-bound oxygen, or moisture from the oil; and that the heating and other steps preparatory to delivery of the oil to the de hydrogenation reactor are similarly conducted.

I have found when using the above described form of flash hydroxylation reactor, because of better contact eihciency between the oil and the oxidizing and hydrating media, the brief or practically instantaneous time of the exposure of the oil to the treatment, and the more exact regulation of the variables controlling the reaction, that substantially greater reacting temperatures may be utilized in the treatment without substantial formation of fixed oxidation and other objectionable ring compounds in the oil, than when treating the oil by other methods involving relativelylonger times of treatment There the hydroxylwhich offer greater opportunity for the formation of such objectionable compounds, thus not only increasing the rate of 'productionmany times; but also producing a more uniformly treated product. The flash hydroxylation may be utilized to effect a mild and but partial hydroxylation to the oil by selective diminution of the operating variables such as air, temperature, and oxidation catalyst, or to effect a more intense hydroxylation of the oil by selective intensification of'those variables.

I shall nowgive specific exemplification of runs which have been conducted in accordance with the procedure of my method and in apparatus as herein shown and described, It is tobe' understood that such exemplification is in nowise restrictive,'but that it will be subject to wide varia-' tion in response to a number of conditions. Even different batches of the same sort of oil preferentially ask accommodation in the' conditions of their treatment, and minor variations in the structure of the apparatus also cause variations in the conditions most to be preferred. The example given immediately below is to be understood as conducted on linseed oil as the starting material, such oil being of a commercial quality which has been subjected to the usual refining treatment for'the removal of gum, mucilage, and other colloidal and suspended impurities, and for the removal of excess free fatty acids.

The example is to be considered as illustrating a treatment in the hydroxylation apparatus shown'in Fig. Id of the drawings, and in the dehydroxylation apparatus shown'in Fig. 1b of the drawings, or in closely analogous apparatus. It will be noted that in the example all of the hydrating water is supplied in the form of steam. This is my preferred procedure for several reasons. In utilizing steam, the hydrating medium being in the form of vapor, may be initially commingled with the air which supplies" oxygen for epoxidation, and being in the form of vapor is more uniformly and intimately commingled. with the air than is possible when utilizing'water in liquid state.- Thus, in the use of steam, awater molecule for hydration is associated so directly with an oxygen molecule of the air that the conditions favor simultaneous contact of both with the oil molecule, to 'cause instantaneous hydration of the epoxide as it is formed; Such 1 mechanism serves to inhibit the formation of permanent oxidation products, and renders hydroxylation of the oil molecules more selective. Additionally, the use of steam avoidsthe tendency toward emulsification which is present when water in liquid state is used as the hydrating medium. I Y

Emamplei In accordance with this procedure, linseed oil for treatment was supplied to the hydroxylatingreactor of Fig. Ia .in the manner described in the description of that apparatus, at areacting temperature of about 165 F., and at the rate of about 1000 lbs. per hour. Air for oxidation, preheated to a temperature of about165f" F., was supplied at a rate of about 275 cubic feet per minute. Steam for hydration was supplied at a rate of about 225 lbs. per, hour, being in accordance with the disclosure of the reactor .to which reference is made, commingled with the air to pass upwardly with it through the several reaction trays of the apparatus; A reduced pressure of about 20 inches of mercury was maintained withinthe reactor during the;

' free of hydroxyl and other 18 process, substantially to prevent condensation of the steam at the reaction temperature. The oil subjected to treatment passed downwardly through the reactor in the manner described in connection with the apparatus; and with the size and arrangement of apparatus used, the oil was subjected to treatment for a period of about 30 minutes'during its progress through the reactor.

Treatment under the conditions given resulted in the selective addition of hydroxyl groups to the remote pairs of unsaturate carbon atoms of the linolenic and linoleic acid glycerides of the oil composition without substantial oxidation, or hydroxyl group addition, to those unsaturate carbon atoms of the linolenic, linoleic, or oleic acid glycerides lying next toward the glycerol radical of the glycerides. In terms of hydroxyl value, the treated oil showed a hydroxyl value of about 210 as compared with an initial hydroxyl value of about 4.

The linseed oil hydroxylated as above, in preparation for treatment in a dehydroxylator of the sort shown in Fig. Ib, was subjected to a deaerating temperature and reduced pressure of about 3 to 5 mm. of mercury, and was raised from a, temperature of about 180 F. to about 360 F. with addition of a suitable dehydrating catalyst, which specifically consisted of about 0.5% sodium acid sulphate. The oil was then heated to a temperature of about 475 F. and free fatty acids and other volatile compounds were flashed off. 1

The oil thuspreparedfor condensive dehydroxylation wasthen treated in accordance with the, procedure given in the description of the apparatus of Fig. lb. As closely as could be estimated, theoil was brought in a thin film and under a reduced pressure of about 3 to 5 mm. of mercury to a temperature progressively increased during a period of about 5 seconds to a maximum of about 610 F., and was immediately cooled to a temperature of about 300 F. As will have been apparent from the discussion associated with the description of the condensive dehydroxylating apparatus, this flash condensive dehydrating primarily is rendered possible by the fact that the oil'is subjected to treatment in a thin film, so that within a short period of time it may be raised to a high temperature and the temperature reduced to below: a point in which heat-polymerization will occur in the oil. During the treatment the dehydroxylating reactor was maintained under a reduced pressure of about 3 to 5 mm. of mercury, and the water evolvedby the condensive reaction was instantaneously removed from the thin rapidly flowing stream-pf oil. Likewise relatively volatile materials in the oil, such as fatty acids, reduced glycerides, and other volatile non-drying contaminates, such as aldehydes, ketones, and oil decomposition compounds which may have resulted from the prior'treatment to the oil were vaporized and eliminatedfrom the flowing stream of the oil. The treated oil was thus substantially addition groups, and of saturated and other non-drying contaminates.

The oil subjected to the had been converted from, an oil having the usual drying properties of linseed oil to one having a high degree of conjugate unsaturation, with high heat-reactivity and improved film-forming properties. The oil had been converted from one initially requiring about minutes to gel under standard gelation test conditions, to one that will gel under the same conditions in about 15 minforegoing treatment utes. The oil also had a desirably low viscosity, its increase in viscosity by the above described treatment being from an initial of about 4 poises to about 18 poises, and because of the minimized formation of fixed oxidation products during the hydroxylating reaction the oil had a desirable light color. Because of the distilling or stripping action at high temperature and reduced pressure, the oil was substantially neutral, having a F. F. A. of about 0.15%.

Example 2 A mixed oil, consisting 50% of commercial refined linseed oil as in Example 1 and 50% of refined desaturated soya bean oil, was subjected to treatment in apparatus combining a hydroxylator as in Ia. with a condensive dehydroxylator as in Fig. Ib. The conditions were substantially identical with those given above in Example 1. By this treatment, the mixed oil was converted from one requiring about 60 minutes to gel under standard gelation test conditions, to one that gelled under the same conditions in about to 12 minutes. The viscosity of the treated oil was about 10 noises.

It may be noted that in treating soya bean oil and like oils having a large proportional content of saturates and semi-saturates it is desirable, as hereinafter more fully explained, to desaturate the oil before treatment.

Example 3 A so a bean oil which had been refined, as was the linseed oil of Example 1, but which. contained its total initial content of the glycerides of saturate fatty acids and oleic acid glyceride, was subjected to treatment in a hydroxvlation reactor such as is shown in Fig. Ia and a condensive dehvdroxylator such as is shown in Fig. 1b. In treating this oil, hydroxylation was carried to a point of substantial com letion rather than selectively performed as in the treatment of the linseed oil and the mixed oil of Examples 1 and 2. In so doing, the conditions of the hydroxylation reaction were intensified. Assuming that the oil was fed to the reactor at a rate of about 1000 lbs. per hour, air heated to about 190 F. was supplied at a rate of about 325 cubic feet per minute. Hydrating steam was supplied at a rate of about 350 lbs. per hour in order to give assurance of an abundance of hydrating medium.

The oil itself was pre-heated to the same temperature as the air, namely to about 190 F.. in order to provide a reaction temperature in that order. The reactor was maintained at a reduced pressure of about inches of mercury in order to prevent condensation of the steam.

The untreated soya bean oil required about 220 minutes to gel under standard gelation test conditions. and the treated oil gelled under the same conditions in about 22 minutes.

Example 4 Linseed oil of the sort and in the condition described was subjected to hydroxylation in a hy- I minute and was atomized with steam supplied at a rate of about 400 lbs. per hour. The interior of the reactor was maintained at a reduced pressure of about 20 inches of mercury.

The oil treated by this procedure corresponded very closely to the oil treated by the procedure of Example 1.

It is to be understood that in all of Examples 2, 3 and 4, the condensive dehydroxylation operation and the steps by which the hydroxylated oil was prepared for that stage of the process were identical with those described in Example 1.

The foregoing examples point the direction in which adjustment may be made in the several 1 variables involved in the process, in accordance with the properties of the starting oil, the desired properties of the product oil, and the influence of the apparatus used upon preferential procedure.

Returning to the chemical mechanism involved in my novel treatment of drying oil, it will be considered that linolenic acid glyceride and lneolio g yceride the glycerides acted upon in the treatment. It will be assumed, also, that the treatment has been a selective one in which hydroxylation followed by condensive dehydroxylation has been effected at a desired point of attack in the acid radical of the oil molecule. The following formulae will illustrate the change effected in the acid radical of the glyceride, the glycerol radical being omitted for the sake of simplicity.

The linolenic acid radical (313001802) may be represented as follows:

Formula A H H C COOH Observing the formula, it is seen that the carbon atoms in the 9-10 positions are linked with a double bond, as are also the carbon atoms in the 12-13 positions and in the 15-16 positions.

If, then, hydroxyl addition is made at both the carbon atoms in the 15-16 positions we obtain Formula B, as follows:

Formula B (H32C1s04) Formula B shows the selectively hydroxylated acid radical before condensive dehydroxylation, with both the carbon atoms in the 15-16 positions saturated by addition of an OH group.

Formula C shows the acid radical after condensive dehydroxylation as follows:

Formula C (H2sC1sO2) urznuuuuuns HHHHHHEHHH H1 In this modification of the structure, a hydrogen atom in the 14 carbon position and a hydrogen atom in the 17 carbon position have been involved in a condensive reaction with adjacent hydroxyl groups b which two molecules of water are formed. The removal of those hydrogen atoms has resulted in the formation of double bonds between the 16 position carbon and the 17 position carbon, and between the 14 and the 15 position carbons. The double bond linking the carbons in the 13 and the 12 positions has remained unaltere'cL'as has also the isolated double bond between the carbons in the 9-10 positions.

From the above, it will be seen that the result is to produce a novel 'glyceride, in which the acid radical has three double bonds in conjugate relation, in addition to one initial double bond which is still in non-conjugate position. Also, it will be seen that at each original pair of unsaturate carbon atoms the hydrogen atoms adjacent both the carbons hav'e gone to form the two molecules of water,' so that double bonds have been introduced in'both directions from the double bond originally present.

The effect is analogous in acid glycerides. The formula for linoleic acid is as follows:

Formula D (HszCmQz) unneran It will be seen in this formula that the linoleic acid radical has two isolated double bonds, one between the carbons in the 9-10 position and the other between the carbons in the 12-13 position. It has been explainedthat *hydroxylation is effected at the 12-13 carbons'morereadily than at the carbons in the 9-10 position. The linoleic acid glyceride being selectively hydroxylated, the

structure will then appear as follows;

m nu

This effect is to add hydroxylfgroups at the carbon atoms in the 12 and 13 positions, which upon condensive dehydroxylation, as shown above, involves the hydrogen atoms in the '11 and 14 carbon positions, the modified structure derived from the linoleic acid radical of the oil molecule then will have double bonds in the 9-10, 11-12, and 13-14 positions in accordance with the following formula:

- Formula F (Hacmoz) Formula G (HaoCmOz) g H o E If we assume that the oil treated is linseed oil,

moms

moral:

mobile consisting 24% of'linolenic acid.'glyceride,.and

62% linoleic acid glyceride;.,with, 5% oleic acid glyceride, and 9% of the glycerides of saturated fatty acids, it will be seen that the treatedj'oil has a total reactivity corresponding very closely to that Of China-wood oil, although the points the case of linoleic" hydroxylation be restricted to the remote unsaturate carbon atoms in the carbon chains 'of the molecules attacked) and then subjected to condensive dehydroxylation, the resultant product derived from natural soya bean oil would consist about 50% of a glyceride responding substantially to the formula for eleostearic acidglyceride, about 6% of a glyceride containing threeconjugate double bonds, and one nonconjugate "double bond, about glyceride, and may have about 14% glycerides of saturated fatty acids.

of unchanged Such product oil is a good drying oil. Further to improve 1 the properties of such product oil, the content of the glycerides of saturated fatty acids and of unchanged oleic acid g'lycerides desirably may be removed by solvent extraction, in accordance with any of the various solvents and procedures which are well-known for the separation of saturates and semi-saturates from the unsaturate fatty'acid glycerides; and with any of the wellknown suitable solvents for that purpose, such as those of the class comprising actone, ketones, and the-higher molecular weight alcohols. It is to be understood that linseed oil and other oils treated in accordance with my method similarly may be subjected to solvent extraction, in the event their non-reactive content is too great to give them the ability to form films of a desired hardness. It is also to be understood that such oils may be subjected to solvent extraction substantially to remove the saturated non-drying components from the oil prior to subjecting it t to treatment and the concentrated unsaturated components utilized as the starting my product oil.

An instance in which selectivity is of particularly great importance is presented by the fish oils, which contain in addition to a moderate content of linoleic acid 'glyceride and. linolenic material for acid glyceride, a moderate content of the highly unsaturate and non-conjugate glycerides,'such as clupanadonic acid, containing more than 18 and up to 26 carbon atoms in their carbon chain, and initially having from c to 6 points of unsaturation in their structure. 1

I have found in treating such oils to obtain what is in practical effect a flash hydroxylation'; as in the'manner which I have described with reference to a reactor of the type shown. in Fig. VII of the drawings, that in the hydroxylation treatment the addition of hydroxyl groups to the linoleic acid and linolenic acid radicals proceeds proportionally with the addition of hydroxyl groups in the fish oil acid radicals. The increased unsa uration and conjugation in those radicals is bal- 'anced' sufficiently by the greater length of the carbon chain and the proportionally greater molecular weight as compared with linoleic and linolenic acids, to give an oil of approximately uniform hydroxylation.

It may be stated that my invention resides primarily in treating a drying oil having a substantial content ofthose unsaturate iattyacid radiof oleic acid calswhich containiatleast l8carbon atoms,-andsort to which the treatment is directed are hydroxylated either fully or in less than maximum order, with consequent control of the extent to whichtheir polymerizing reactivity is increased; and resides in condensively:dehydroxylating by means of aflash' dehydration which efiectively dehydroxylates the hydroxylated oil, without decomposing the oil or unduly increasing its viscosity.-.

To the extent that the starting oil consists. of reactive glycerides, that is glycerides of fatty acids having at least 1-8 carbon atoms'in the carbon chain and at least two pairs of carbon atoms linked by double bonds, the oil is increased in iodinevalue from a very substantial percentage increase to an increase of more than 100%. The increase in unsaturation, or iodine value, is inevitably accompanied by conjugation, because each double bond-which'origina lly links two carbonzatoms is replaced by two double bonds each linking one-of the originally unsaturate carbon atoms with another adjacent carbon atom.

Considering the two commercial drying oils considered above, namely linseed oil and soya bean oil, it-has been explained that the linseed oil has an initial iodine value of about 180 and the soya bean-oil has an iodine valueofabout 140. By selectively subjecting these oils to treatment. in accordance :with my method under controlledconditions, I am able to increase the iodine value of the linseed (with conjugation) to from about 200 to about 350. Similarly, I am able-to increase the iodine value of the soya bean oil (with conjugation) to from about 150 to about 250.

By virtue of an hydroxylation treatment which is effec-ti-verapidly to produce epoxide formation with substantially simultaneous hydration, the oil is approximately free of permanent oxidation and other objectionable compounds. By virtue of condensive dehydration eifectively performed the initial viscosity of the product oil is not undesirably increased.

My drying oil product thus is an improved oil resultant from an oil having a substantial initial content of non-conjugate unsaturate reactives,

in which unsaturation has been increased with an increase in conjugation which matches the increase in unsaturation. That is, increased unsaturation is efiective proportionally to product conjugation. The position of the unsaturation and of the conjugation in the molecules of the treated oil is determinate.

The foregoing disclosure of my invention has been made full and detailed, in order that the invention may be fully understood and that full I;

benefit may be derived from it. As above indicated, however, it is to be taken that such detail disclosure is descriptive and not restrictive, and that the scope of my invention is to be limited only by the definition of my invention as contained in the appended claims.

I claim as my invention:

1. The method of improving the heat reactivity and film forming properties of non-conjugate glyceride oils containing a substantial. proportion of components havingtwo or more pairs of unsaturatedatomsin'their carbon chain, which com prises subjecting, -.aconfined continuously flow-- ing stream 01: the oil divided into a plurality of successive shallow pools while passing down-- wardly through a treating vessel; to selective hydroxylation by intensively blowing said pools in the presence :of a hydroxylating' catalyst with upwardly flowing stream of oxygen ccntz ring gas, intimately mixed with hydrating steamin amount sufficiently greater than the theoretical amount required to hydrate the epoxy groups to insure the hydrationof all of the epoxy groups:-

selectivelyadded thereto bysaid blowing at a selective epoxidation reaction temperature wit the range of F. to 250 F. for approximately 30 minutes, sufiicientto selectively add hydroxyl groups to the remote pairs of unsaturated carbon atoms of said unsaturated components without substantial oxydative polymerization thereof or oxygenation of the 9-10 unsaturated carbon atoms present -in=said.oil composition, then quick-1y removing such hydroxylated oil from the zone of oxidation, removing free-waterand air therefrom and subjecting-the oil to flash-dehydrowlation by quickly heating athin rapidly flowing stream at .a .reducedpressurein the presence of a dehydrating catalyst atv a determinate iiasll rlehydrating temperature within the range o1" 500 to 700 F. for abrief, substantially non-thermal polymerizing period of time about one minute or less correlated to said dehydrating temperature, effective to produce a substantially non-oxidized, non-polymerized conjugate type drying oil product containing a substantial proportion of glycerides having one more double bond than the corr sponding unsaturated components of the said starting oil from which they were derived.

2. The method as set forthin claim 1 wherein said glyceride-oils include linolenic glyceride and said epox-idation temperature is within the range of 130 F. to Frand wherein hydroxyl groups are selectively added at the 15-16 carbon positions of said linolenic'glyceride, to produce an oil product-having a substantialproportion of glycerides having double bondsat its 9-10, 12-13, 14-15 and 16-17 carbon positions.

3. The method as set forth in claim 1 wherein said glyceride oils include linoleic glyceride and said epoxidation temperature is within the range of 200 F. to 250 F. and wherein hydroxyl groups are selectively added at the 12-13 carbon positions of said linoleic glyceride to produce an oil product having a substantial proportion of glycerides having double bonds at its 9-10, 11-12, 13-14 carbon positions.

4. The method of improving the drying prop erties of linseed oil as set forth in claim 2.

5. The method of improving the drying properties of soy bean oil as set forth in claim 3.

ROBERT A. CARLETONJ REFERENCES CITED The following references are oi'record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,565,249 Berry Dec. 15, 1925 2,083,220 DeGroote June 8, 1937 2,194,250 Turek Mar. 19, 1940 2,278,425 Colbeth. Apr. 7, 1942 2,308,152 Boone Jan. 12, 1943 2,317,362 Colbeth Apr- 27, 1943 2,361,793 Porter an; 1. Oct. 31, 1944

Claims (1)

1. THE METHOD OF IMPROVING THE HEAT REACTIVITY AND FILM FORMING PROPERTIES OF NON-CONJUGATE GLYCERIDE OILS CONTAINING A SUBSTANTIAL PROPORTION OF COMPONENTS HAVING TWO OR MORE PAIRS OF UNSATURATED ATOMS IN THEIR CARBON CHAIN, WHICH COMPRISES SUBJECTING, A CONFINED CONTINUOUSLY FLOWING STREAM OF THE OIL DIVIDED INTO A PLURALITY OF SUCCESSIVE SHALLOW POOLS WHILE PASSING DOWNWARDLY THROUGH A TREATING VESSEL, TO SELECTIVE HYDROXYLATION BY INTENSIVELY BLOWING SAID POOLS IN THE PRESENCE OF A HYDROXYLATING CATALYST WITH AN UPWARDLY FLOWING STREAM OF OXYGEN CONTAINING GAS, INTIMATELY MIXED WITH HYDRATING STEAM IN AMOUNT SUFFICIENTLY GREATER THAN THE THEORETICAL AMOUNT REQUIRED TO HYDRATE THE EPOXY GROUPS TO INSURE THE HYDRATION OF ALL OF THE EPOXY GROUPS SELECTIVELY ADDED THERETO BY SAID BLOWING AT A SELECTIVE EPOXIDATION REACTION TEMPERATURE WITHIN THE RANGE OF 130*F. TO 250*F. FOR APPROXIMATELY 30 MINUTES, SUFFICIENT TO SELECTIVELY ADD HYDROXYL GROUPS TO THE REMOTE PAIRS OF UNSATURATED CARBON ATOMS OF SAID UNSATURATED COMPONENTS WITHOUT SUBSTANTIAL OXYDATIVE POLYMERIZATION THEREOF OR OXYGENATION OF THE 9-10 UNSATURATED CARBON ATOMS PRESENT IN SAID OIL COMPOSITION, THEN QUICKLY REMOVING SUCH HYDROXYLATED OIL FROM THE ZONE OF OXIDATION, REMOVING FREE WATER AND AIR THEREFROM AND SUBJECTING THE OIL TO FLASH-DEHYDROXYLATION BY QUICKLY HEATING A THIN RAPIDLY FLOWING STREAM AT A REDUCED PRESSURE IN THE PRESENCE OF A DEHYDRATING CATALYST AT A DETERMINATE FLASH DEHYDRATING TEMPERATURE WITHIN THE RANGE OF 500* F. TO 700*F. FOR A BRIEF, SUBSTANTIALLY NON-THERMAL POLYMERIZING PERIOD OF TIME ABOUT ONE MINUTE OR LESS CORRELATED TO SAID DEHYDRATING TEMPERATURE, EFFECTIVE TO PRODUCE A SUBSTANTIALLY NON-OXIDIZED, NON-POLYMERIZED CONJUGATE TYPE DRYING OIL PRODUCT CONTAINING A SUBSTANTIAL PROPORTION OF GLYCERIDES HAVING ONE MORE DOUBLE BOND THAN THE CORRESPONDING UNSATURATED COMPONENTS OF THE SAID STARTING OIL FROM WHICH THEY WERE DERIVED.

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