US2404537A - Treatment of hydrocarbons - Google Patents

Description

Patented July 23, l946 TREATMENT OF HrDItooARBo s Louis Schmerling and Vladimir N. Ipatiefl, Chi- ,cago, IlL, assignors to Universal Oil Products Company,

I ware v Chicago,,Ill., a corporation of Dela- No Drawing. Ap'Dlicatioh July 6; 1942,

Y Serial No. 449,946

'16 claims. (01. 260-15834) This invention relates to the treatment of iso v paraffinichydrocarbons to produce therefrom:

, branched chainparaflinic hydrocarbons-oi higher molecular weight; 1 In a'more'specific sense, th-is invention'is concerned withsaznovelproc'esskfor interacting alkylatable paraflinic hydrocarbons,

herein termed isopai'affini'cuhydrocarbons, with alkyl esters of chloroformicacidto produce higher boiling'parafiihic hydrocarbons of gasoline boiling range.

In one specific embodiment, the present invention relates to a process for synthesizing hydrocarbons which comprises reacting an isoparafiinic hydrocarbon with an alkyl chloroformate under alkylating conditions in the presence of a Friedel-Crafts type metal halide catalyst.

Considerable'quantities of butanes, pentanes, and other paraifinic' hydrocarbons of relatively low molecular Weights are available in the relatively light hydrocarbon material condensable from natural gas and usually referred to as casing head gasoline. These relativelylight components of casing head gasoline also includevcertain amounts of the corresponding isoparafiins, namely, isobutane, isopentane, etc. The relatively low boiling normal paraflins may also be isomerized into the corresponding isoparaffins by suitable treatment. Further quantitiesofjbutanes and pentanes are formed as by-products'in the cracking of petroleum fractions and of other hydrocarbon oils to producegasoline.

Alkyl esters of chloroformic acidhwhic'h are utilizable as alkylating agents in the process of the present invention have the general formula: ClCOOR, in which R represents'an alkyl group. Alkyl chloroiormates are readily obtainable by the treatment of an alcohol with phosgene, Thus, as indicated in the following equation, reaction of 1 molecule of phosgefne with 1 molecul e of iso pro'pyl alcohol results in .the' formation oi 1 ,molecule each of isop-ropyl chloroformate andehyd'rogen chloride: H i v 03H10H +0001, 0100065111 l am V the respective boiling points'which are listed as" follo'w's:--* 1 :3: :wi'

Friedel-Crafts type metal halides which are; I utilizable as catalysts for promotingthe alkyla tion of an isoparaffin with an alkyl chlorofor= matein accbrdance with thepresentinvention in-I s c1ude;suchjsaltfs as aluminum chloride;aluminum bromide, zi chloride, ant-i lyst in suchalkylation' reactions because ;it

reaction under specified conditions.

methane. Other Friedel-Crafts-type metal halides andparticularly chlorides may be added ,to

the aluminum chloride or to its'solution ior thepurpose, of modifying the, activity of the num chloride.-

iWhile amy audn r isopara ili nic by alkyl chloroformates vmayibe .efie'cted in. the.

' presence oflaluminumchloride andother Fried Crafts type catalysts. at temperature 0 1mm about gzo to. about-1 peraturepf from about-10 1 ing range with relatively srnall amounts of jun- Isopropyl Phos- Isopropyl Hydrov alcohol gene chloroformate gen ride Some of the alkyl chloroformates which are often referred to as alkyl 'chlorocarbonates have desira'bleside reactions, such as polymerization,

formation of organic compounds I containing Q chlorine, etc, it is desirable t maintain a molar excess of isoparailin hydrocarbon-to alkyl chloromm? ,pressure chloride, zirconium chloride, ferric m m ch de. i mu flp l r and others; We prefer, however, to employ alu-j minum chlorideas the Friedel craifts type; cata" V ,c, ne u' elr Meme. to about 7Q? C, is preferred; Pressuresutilizable inlthe'process may varyfrom'substantially atmospheric to about 50.. atmospheres or more. Inorder to obtainwhigh yields of hydrocarbon products of gasoline boilformate throughout the entire reaction period. Generally from about 2 to 25 molecular proportions of ,isoparafiinic hydrocarbons should be present per molecular proportion of alkyl chloroformate introduced to an alkylation reaction mixture in order to form a substantially saturated hydrocarbon material and to avoid undesirable polymerization and decomposition reactions. v

The reactions which occur during the treat ment of an isoparaflinic hydrocarbon with an alkyl chloroformate in the presence of a Friedel-f Crafts type metal halide, or m ture of said metal halides, apparently involve the combination of the isobutane with the ester of chloroformic acid accompanied by splitting out of'carbon; dioxide and hydrogen chloride as illustrated by the following equation: e

A101: iC4Hm C1C0OQ3H7 C1Hm 002 1101 Isobu- Isopropyl Hep- Oar- -Hyd.ro- V tane chloroformate tane .bon lien; diox ch: g

' ide ride 1' V The us'eof chloroformates (or chlorocarbonates as they are often called) :has the advantage over i the similar us of other esters in that no :iree

viding a mixing zone through which the reacting organic compounds and catalyst are passed un der alkylating conditions and in which sumcient time is given for the completion of the desired isoparafiin alkylation. -The products from such;

a reaction zone are then directed to a separating zone inwhich the alkylationproducts are separatedfrom. the unconverted iso'paraifinic hydrocarbon, catalyst, and amixture of hydrogen chloride and carbon dioxide. The recovered unconverted isoparafiinic hydrocarbonand catalyst are then recycled to contact with the mixture of 150'- I parafi'lnic hydrocarbon and alkyl chloroformate being charged to the process. Hydrogen chloride may also be recycled if desired.

, The activity of the Friedel-Crafts type catalyst employed in the process is dependent upon the w particular metal-"halide ormetal halide mixture so utilized.

, to catalyze the alkylation are not necessarily equivalent in their action particularly when react ing differentisoparaffins with various alkylchloorganic acid'is produced during such reaction.

' Acco'rdingly,-the aluminum chloride used as 'cata-- lyst in the process does not 'form an aluminum chloride-organic acid complex, and hence only catalytic and not stoichiometric amounts of aluminum chlorideare'necessary for the reaction;

Although'the mechanismsof the reactionslin volved are not understood completely and should not be construed to limit the scope of the 'inyenf tion, the interaction, for example, of'isobutanez,

with isopropyl chloroformate yields heptanes. which include 2,2,3-trimethylbutane, generally.

known as triptane. Heptanes so formed may react rurther with an additional quantity ofthe alkyl chloroformate such as isopropyl chloro-- forrnate to form a parafiin hydrocarbon of still higher molecular weight such as -a decane. Dec-I anes'and other hydrocarbons :of relatively high molecular weight may undergo decomposition and further conversion reactions in the presence of the catalyst to produce'lowenand higher boiling hydrocarbons which are generally paraffinic in naturelg The process of the present invention may be 7 carried 'out either in batch or continuous types of operation. In batch type operation, the preferred procedureis .to, agitate a mixture of paraflinic hydrocarbon and catalyst at the chosen operating temperature and pressureand'to introduce gradually thereto an alkyl chloroformate or a.

mixture comprising essentially an alkyl chlorov formats and anisoparafiinic hydrocarbon or. an

of 'mixing suflicient to effect substantially complete reactionof thealkyl chloroformat'e withisoparaffinicjhydrocarbon fraction; After a time the isoparafiimthe isopalis flin being present ;in.

excess oftli'ea1kyl chloroformateat all times, the

agitation islstojpped and the reaction mixture is separated into used catalyst, unconverted isoparaiiin; alkylation product, and a mixture of hydrogen chloride an'd carbon dioxide, the latter two materials k resulting from the decomposition of the alkylfchloroformate. The recovered catacovered from a previous alkylation run.,.

'T-heprocess may be made continuous by proe chloroformate 1 Run number Reactants, g.: 7 r Ethyl chloroiormate. 110 110 110 Isobutane 172 168 81 V 172 Aluminum chloride 40 40 :20 .40 Autoclave lining Nickel Glass Nickel Pressure, atm.:

Initial, nitrogen added- 2 1 4 30 7 Maximum 4 1B ,50 25 Final at 20 O 10 18 43 17 Temperature, C 7 40 1 50 Duration of run, hours 5 6 4 7. Products, g.: V

Gondensible'gas 173 70. 152 Liquid hydrocarbon layer 0 27 15 66 Catalyst layer 43 54 28 45 Hydrogen chloride, carbon dioxide, and lcss. 64 38 59' Distn. of hydrocarbon layer,. volume percent: a i Condensible gas -V 3f; (52

Liquid-fractions:

. Below 40 C V 12 8 Between 40 and 75 0-. 30 37 22 Between 75 and 95 0.. .7 7 4 Residue 9 9 Analysis of .condensable gas, mole percent: r r I Ethane .5. 8 Propane 1. 6 -2. Butane--- -77.5 79.6 ;2 79. Ethyl chloride 21.6 16.6 10. Pentane and higher hydr i i bons i 0.9 3. 8 1 12. 4 8

The different Friedel-Crafts type metal halide mixtures which may be employed roformates' having alkyl,1groups of increasing carbon chain length and'degree of branching.

The following examples are given to illustrate the character of'theresults obtained by, the use l l of the. present process, although, the "data present'd' are not introduced with the intention of i the generally broad scope "of the E unduly limiting invention. V

" r EXAMPLEI 'Alkylation of isobutane by ethyl chloroformate was carried out by charging to a rotatable auto;

clave (lined with glass or nickel) a mixture; oi the 'isobutan'e; ethyl chloroformate, and catalyst in the amounts indicatedi n Table I.

Table I. m1/zationlo isobutane with-ethyl "The results given in Table i show that alkylation' occurred in good yields at temperature of 40 C. or higher. It is interesting tonote that 44.8; ethyl chloride, 25.4; pentane and higher the liquidpro'duct boiled at; a relatively low rem-' perature and most'of' it boiled between40- and 75 C. with very little boilingabove' 100 C. a 1

EXAMPLE II A total of' 120 grams'of isopropylchlorofor'mate was added slowly to 'a glassareactor"containing a and 20' grams of aluminum chloride. The reaction temperature was maintainedataboutfthe boiling point of isobutane"under=l fatmosphere pressure by permitting the isobutane to-reflux:

under a well cooled condenser while. the isopropyl chloroformate was" introduced ."graduall'y't'o the reaction mixture 'over a periodof3 hours.

Hydrogen chloride was evolved at aimoderate orless liquid hydrocarbon material and 42 grams of used catalyst having the appearance of a reddish brown oil. In addition to the liquid hydrocarbons and catalyst, the recovered materials comprised 148 grams of condensible gases (chiefly isobutane) and 41 grams of a mixture of hydrogen chloride and carbon dioxide. The relatively large loss of 62 grams was probably due to a mechanical loss of hydrogen chloride and carbon dioxide. The condensible gas consisted of 28.5 mole per cent of propane, 67.2% of butane, and 4.3% of pentanes. The 52 grams of colorless liquid hydrocarbon material recovered in this run represent 125% by weight of the propylene which may be considered available from the isopropyl chloroformate. Distillation separated the liquid product into fractions having the boiling ranges and refractive indexes indicated in Table 2.

- well stirred mixture of 205 grams of isobutan'e- 1 which comprises reacting an iso'paraffinic' hydro- 'we-aaim js ourfiinventionz;

1. A "process for;"s'ynthesi'zirig ydrocarbons r v which comprises 'reactingan iso'paiafl'lnic'*lji'ydr63- carbo'njwitha-n alkyl cliloroforniate uhder alkyl- CIfaftstype inetal halide catalyst. I

, 2, AQ process fonsynthesizing hydrocarbons which comprises: reacting: an isoparaffinic hydro carbon with an alkyl chloroformate at 'a temper-* ature of from about to about 100 C. in the presence fof a at l -Y 3. A process for synthesizing hydrocarbons Friedel Crafts type metal "halide carbonwithan alkyl chloroiorrnalte' at a tempera ture of 'from about '20 to-about- 100" C. under a pressure of, from substantially atmospheric to about 150 atmospheres in the presence of a Friedel Craits type metal halide catalyst.

The increased Crafts metal halide catalyst, whilev main-' tainingfa molarexcess of said isoparafilnic hydr carbon' to said alkyl chloroformate throughout the entire reaction period. 1

5. A process for synthesizing. hydrocarbons 4. A process for synthesizing hydrocarbons which comprises reacting an iso'parafilnic hydro ca'rbon' with an alkyl chloroformate under-jalk'yl:

ating'conditions in the 'presencefot'a Fr iedel which comprises reacting an isoparafl'inic hydrocar bon with an alkyl chloroformate at a temperature of from about 20 C. to about 100 C. under a pressure of from substantially atmospheric to about 50 atmospheres in the presence of a Friedel-Crafts type metal halide catalyst while maintaining a molar excess of said isoparaflinic hydrocarbon to said alkyl chloroformate throughout the entire reaction period.

6. A process for synthesizing hydrocarbons wh ch comprises reacting an isoparafiinic hydrocarbon with an alkyl chloroformate under alkylating conditions in' the presence of an aluminum Table 2.--Distillation of normally liquid hydrocarbon product formed by reactionnf isobutane with isopropyl chloroformate in the presence of aluminum chloride [Charge: 69 cc. (48.7 g.)]

Vol. of traction, cc.

Boiling Fraction No. rgndge, index Refractive halide catalyst 7. A process for synthesizing hydrocarbons which comprises reacting an isoparaflinic hydrocarbon with an alkyl chloroformate under alkylating conditions in the presence of an aluminum chloride catalyst whilemaintaining a molar excess of said isoparaffinic hydrocarbon to said alkyl chloroformate throughout the entire reaction period.

8. A process for synthesizing hydrocarbons which comprises reacting an isoparafiinic hydrocarbon with an alkyl chloroformate at a temperature of from about 20 to about C. in the presence of an aluminum chloride catalyst while maintaining a molar excess of said isoparaffinic hydrocarbon to said alkyl chloroformate throughout the entire reaction period.

9. A process for synthesizing hydrocarbons which comprises reacting an isoparaffinic hydrocarbon with an alkyl chloroformate at a temperature of from about --20 to about 100 C. under a pressure of from substantially atmospheric to about 50 atmospheres in the presence "of an aluminum chloride catalyst while maintaining a molar excess of said isoparaflinic hydrocarbon to said alkyl chloroformate throughized in that said isoparaffinic hydrocarbon com-' prises isopentane.

12. A process for synthesizing hydrocarbons aftingjconditions in the presence of a lfriedelq 7? I which comprises reacting an isoparaflinic hydrocarbon with an alkyl ohloroformate at a temperature of from about 20j toabout 10p-,C.

under'a pressure of from substantially atmos-v pheric to about 50 atmospheres in the presence of aluminum chloride and'another Frie del- Crafts type catalyst while maintaining a molar excess of-said isoparafiinic hydrocarbon to said alkyl chloroformate throughout .the 'entire reaction peri'od.- .7 1

13, A process for synthesizing hydrocarbons which comprises reacting an isoparaffinic hydro: carbon with an alkyl chloroformate ata ,temperature of from about to about 100910.

undera; pressure of from substantially atmlo'se.

pheric to about 50 atmospheres in the presence ofa composite comprising essentially, aluminum from substantially atmospheric-to'about50 at: mospheres in the presence-of an aluminum "chloride catalyst. while maintaining, a molar excess;

of said isobutane to said ethyl 'chloroforrnate throughout the entire reaction period.

15.-A process forsynthesizing hydrocarbons of gasoline boiling range and-high antiknockrvalue whichcomprises contacting one moleculanproportion of ethyl chloroformate and from about 2',

to about molecular proportions of isobutane with an aluminum chloride catalyst at a semiperature of fromr about toabout 100 C.

atmosunder --a pressure of *from substantially pheric to' about atmospheres.= 1

. '16." A process for synthesizing hydrocarbons of gasoline boiling range and high antiknock value chloride anda refractory carrier while maintain-.

ing a molar excess ofsaid isoparaflinichydroe, carbon to said alkyl chloroformate I throughout the entire reaction period,

;14;;A process for'synthesizing hydrocarbons of gasoline boiling range and high antiknock comprises reacting isobutane with value which I V ethyltchloroformate at a temperature of, from "about' io to about 1009 C. under a pressureof which comprises contacting one molecular pro-' portion of a propyl chloroformate -and from'about:

' 2 to about 26 molecular proportions of isobutane "perature of from about 20"-to about C.

with'an aluminum chloride catalyst at a temunder a pressure of from substantiallyatmosw pheric to about 50'atmospheres.

LOUIS SCHMERLING; VLADIMIR N. IPA'IIEER,"