US3409698A - Olefin preparation - Google Patents

Description

United States Patent 3,409,698 OLEFIN PREPARATION George E. lllingworth, Mount Prospect, and George W. Lester, Palatine, Ill., assignors to Universal Oil Products Company, Des Plaines, Ill., a corporation of Delaware No Drawing. Filed June 24, 1966, Ser. No. 560,056 9 Claims. (Cl. 260-682) ABSTRACT OF THE DISCLOSURE An unsaturated hydrocarbon is prepared by contacting a metaborate ester with boron oxide or anhydrous boric acid at a temperature of 150-250 C.

This invention relates to a process for the preparation of olefinic compounds. More particularly, the invention is concerned with a process whereby olefinic hydrocarbons may be obtained from metaborate esters.

The use of olefinic compounds, and particularly olefinic hydrocarbons has increased in recent years. For example, olefinic hydrocarbons may be used as starting materials for the preparation of such varied compounds as rubber, plasticizers, detergents, etc. One specific example of this are relatively long straight chain olefins which are useful as plasticizers in the formation of synthetic plastics and resins, said plasticizer imparting desirable physical characteristics to the finished product. In addition, the long straight chain olefins may be used as alkylating agents which are useful in the preparation of detergents. Heretofore, detergents comprising long chain alkylaromatic sulfonates have been prepared and used as such. However, many of these long chain alkyl substituents were highly branched in configuration. The increasing use of detergents of this type has resulted in contamination or pollution of many streams, rivers, lakes, pools, etc inasmuch as it has now been discovered that detergents of this type are nonbiodegradable. In this respect, the sight of streams, rivers, etc., containing amounts of foam has become increasingly prevalent. In addition, many communities have reported that where individual household septic tanks are involved, it has become likely that tap water is heavily laced with suds due to the contamination of said tanks, Furthermore, the water supply for cities or towns, which depend upon streams or rivers as a source of water supply is also contaminated. In order to combat this disadvantage, detergents which are prepared and used both now and in the future must, of necessity, be biodegradable in nature. These biodegradable detergents must contain long chain alkyl substituents which are straight chained in configuration or which may contain a minimum amount of branching, said branching preferably comprising no more than methyl radicals. This straight chain configuration of the alkyl side chain will permit the organisms which destroy the detergent to, in effect, eat their way up the chain, thereby destroying the molecules and allowing the detergents to be assimilated in the water without concurrent production of undesired long-lasting foam or suds.

Heretofore, one method of obtaining olefinic hydrocarbons, and particularly long chain olefinic hydrocarbons, has been to convert the corresponding alcohols to olefins. One method of accomplishing this result is to form a derivative of the alcohol such as an organic ester and thereafter subject the ester to pyrolysis to effect a 3,409,698 Patented Nov. 5, 1968 cleavage and thus form the desired olefin. However, it has now been discovered that relatively pure olefinic hydrocarbons may be obtained by treating a metaborate ester, and particularly an alkyl-metaborate in the presence of an excess of a boron-containing compound to directly prepare the desired olefinic hydrocarbon.

It is therefore an object of this invention to provide an improved process for preparing olefinic compounds utilizing a borate ester.

A further object of this invention is to provide an improved process for preparing olefinic hydrocarbons utilizing an alkyl-metaborate as the starting material.

In one aspect, an embodiment of this invention is found in a process for the preparation of an unsaturated hydrocarbon which comprises contacting a metaborate ester with a boron-containing compound at a temperature in the range of from about C. to about 250 C., and recovering the resultant unsaturated hydrocarbon.

A further embodiment of this invention is found in -a process for the preparation of dodecene which comprises contacting dodecyl metaborate with an excess of boric oxide at a temperature in the range of from about 150 C. to about 250 C. and recovering the resultant dodecene.

Other objects and embodiments will be found in the following further detailed description of this invention.

As hereinbefore set forth, the present invention is concerned with an improved process for obtaining olefinic hydrocarbons utilizing metaborate esters as the starting material. By utilizing this improved process which is hereinafter set forth in greater detail, it is possible to obtain relatively pure olefinic hydrocarbons. The process of the present invention is effected by treating metaborate esters, and particularly alkylmetaborates with an excess of a boron-containing compound at a temperature in which the alkylmetaborates alone are stable. The term alkylmetaborate as used in the present specification and appended claims will refer to both aliphatic and ali-cyclic metaborates. Specific examples of these alkylmetaborates include those which contain from 4 to about 20 carbon atoms such as n-butylmetaborate, sec-butylmetaborate, t-butylmetaborate, n-pentylmetaborate, sec pentylrnetaborate, t-pentylmetaborate, n-hexylmetaborate, sec-hexylmetaborate, t-hexylmetaborate, n-heptylmetaborate, secheptylmetaborate, t-heptylmetaborate, the corresponding octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eiocosyl metaborates, etc., cyclopentylmetaborate, cyclohexylmetaborate, cyclooctylmetaborate, cyclododecylmetaborate, etc.

The desired olefins may be prepared from the alkylmetaborates by treating said metaborates with an excess ranging from about 0.5 to about 2 moles of boron-containing compound per mole of alkylmetaborate. Suitable boron-containing compounds comprise boric oxide and anhydrous boric acid. The pyrolysis is effected at temperatures ranging from about 150 to about 250 C. and preferably, as hereinbefore set forth, at temperatures in which the alkylmetaborate alone is stable.

The process of this invention may be effected in any suitable manner and may comprise either a batch or continuous type operation. For example, when a batch type operation is used, a quantity of the alkylmetaborate and an excess of the boron-containing compound are placed in an appropriate apparatus such as a flask provided with heating, stirring and condensing means. The apparatus is then heated to the desired reaction temperature while the olefin distills out as overhead reduced pressure being desirable in the case of higher olefins. The product is then recovered, dried over a drying agent such as anhydrous sodium sulfate, calcium chloride, etc., to remove water and subjected to fractional distillation. The desired olefins are then recovered from this distillation.

It is also contemplated within the scope of this invention that the process described herein may be eflected in a continuous manner of operation. When such a type of operation is used, a quantity of the alkylmetaborate and the boron-containing compound are continuously charged to the reaction vessel which is maintained at the proper operating conditions of temperature and pressure. Upon completion of the desired residence time, the reactor effluent is continuously withdrawn and subjected to a separation treatment wherein the desired reaction product is separated from unreacted alkylmetaborate, boron-containing compound and Water. The unreacted alkylmetaborate and boron-containing compound are recycled to form a portion of the feed stock while the desired olefins are recovered. Examples of olefins which may be prepared according to the process of this invention include l-butene, 2-butene, l-pentene, 2-pentene, l-hexene, 2- hexene, l-heptene, 2-heptene, the isomeric octene, nonenes, decenes, undecenes, dodecenes, tridecenes tetradecenes, pentadecenes, hexadecenes, heptadecenes, octadecenes nonadecenes, eicosenes, etc.

The following examples are given to illustrate the process of the present invention which, however, are not intended to limit the generally broad scope of the present invention in strict accordance therewith.

EXAMPLE I To illustrate the process described herein, 100 v (0.587 mole) of mixed dodecanols and 20.3 g. (0.294 mole) of boric oxide were heated in a flat bottom, magnetically stirred flask provided with condenser means for a period of 90 minutes. During this time, water was continuously removed by means of the water-trap. However, water was the only product recovered during this heating period. The mixture was allowed to cool and an additional 20.3 g. of boric oxide was added. The mixture was then slowly heated to a temperature of 220 C. at which point the borate esters decomposed and a mixture of olefin and water was distilled overhead. The product comprised 81 g. A gas-liquid chromatograph analysis of this product disclosed 97.7% of a mixture of dodecenes along with 1.5% of dodecanol and 0.8% of dodecanones. The product was then dried over anhydrous sodium sulfate, fil tered, refluxed for 12 hours with sodium pellets, and distilled under reduced pressure. The cut boiling at 9293 C. at 13 to 14 mm. pressure comprising mixed dodecenes was recovered.

EXAMPLE II In this example, 130 g. (1.0 mole) of 2-octyl alcohol and 34.8 g. (0.5 mole) of boric oxide were placed in a three-necked flask provided with a stirring rod, condenser and a nitrogen lead. The mixture was heated to a temperature of about 235 C., during which time 19 g. of water was removed. The mixture was allowed to cool to room temperature and 20 g. of additional boric oxide were added. The temperature was then slowly raised to about 160 C. at which point olefins began distilling overhead. The overhead product was subjected to a gas-liquid chromatograph analysis and found to contain 98% of 1- octene and 2-octene.

EXAMPLE III A mixture of 1 mole of hexyl alcohol and 0.5 mole of boric oxide is placed in a flask which is stirred for a period of about 90 minutes while heating the mixture to a temperature of about 255 C. During this period, water is continuously removed overhead but there is no decomposition of the alkylmetaborate. At the end of this minutes, the flask and contents thereof are allowed to cool to room temperature. An additional 0.5 mole of boric oxide is added to the solution and the mixture is slowly heated to a temperature of 200 C. with constant stirring. The borate esters will decompose and a mixture of olefin and water will be distilled overhead. The product is dried to remove the water and distilled under reduced pressure. The desired mixture of hexenes will be separated therefrom.

EXAMPLE IV In this example, a mixture of decyl alcohol 1.0 mole) and anhydrous boric acid (0.5 mole) i treated in a manner similar to that set forth in the above examples. At a temperature of about 250 C., the only product which is recovered by distillation comprises water. After cooling the mixture to room temperature, an additional mole of anhydrous boric acid is added thereto and the resulting mixture again heated with constant stirring. At a temperature of about 220 C., a mixture of olefins and water will distill overhead. The reaction product which is recovered, is dried and subjected to fractional distillation under reduced pressure, the desired decenes being recovered therefrom.

EXAMPLE V In this example, 0.5 mole of mixed linear hexadecanols and 0.25 mole of boric oxide are heated to a temperature of about 250 C. with continuous stirring. After removal of the water overhead, the mixture is allowed to cool to room temperature. An additional 0.25 mole of boric oxide is added and the mixture is again slowly heated to a temperature of 220 C. while the pressure is reduced to mm. At this point, a mixture of olefin and water will begin to distill overhead. Upon completion of the reaction, the product is dried to remove the water and subjected to fractional distillation, the desired hexadecenes being recovered therefrom.

We claim as our invention:

1. A process for the preparation of an unsaturated hydrocarbon which comprises contacting one mole proportion of a metaborate ester with from about 0.5 to about 2 mole proportions of a boron-containing compound selected from the group consisting of boron oxide and anhydrous boric acid at a temperature in the range of from about C. to about 250 C. and at which temperature said ester alone is stable, and recovering the result ant unsaturated hydrocarbon.

2. The process as set forth in claim 1, further characterized in that said boron-containing compound comprises boron-oxide.

3. The process as set forth in claim 1, further characterized in that said boron-containing compound comprises anhydrous boric acid.

4. The process as set forth in claim 1, further characterized in that said metaborate ester comprises an alkyl metaborate.

5. The process as set forth in claim 4, further characterized in that said alkylmetaborate comprises hexylmetaborate and said unsaturated hydrocarbon comprises hexene.

6. The process as set forth in claim 4, further characterized in that said alkylmetaborate comprises decylmetaborate and said unsaturated hydrocarbon comprises decene.

7. The process as set forth in claim 4, further characterized in that said alkylmetaborate comprises dodecylmetaborate and said unsaturated hydrocarbon comprises dodecene.

8. The process as set forth in claim 4, further characterized in that said alkylmetaborate comprises hexadecylmetaborate and said unsaturated hydrocarbon comprises hexadecene.

9. The process as set forth in claim 4, further characterized in that said alkylmetaborate comprises octylmetaborate and said unsaturated hydrocarbon comprises octene.

References Cited UNITED STATES PATENTS Cerrione 260462 Marshall 260682 Becker 260-462 Starks et a1. 260-462 6 OTHER REFERENCES Steinberg: Orangoboron Chemistry, Wiley, N.Y., 1964, pp. 10, 47-8, 118-22, 4557.

Brandenberg and Galat: Olefins From Alcohols, J. 5 Am. Chem. Soc. 72, 3275-6 (1950).

DELBERT E. GANTZ, Primary Examiner.

G. E. SCHMITKONS, Assistant Examiner.