US2381987A - Process for producing unsaturation in hydrocarbons - Google Patents

Description

Patented Aug. 14, 1945 PROCESS FOR PRODUCING UNSATURA- TION IN HYDROCARBONS Bernard H. Shoemaker, Whiting, Ind, and Edmond L. dOuvllle, Chicago, Ill., assignors to Standard Oil Company, Chicago, 111., a comration of Indiana No Drawing. Application March 30, 1942,

Serial No. 436,768

5 Claims.

The present invention relates to a process for the production of normally non-gaseous polyenes from hydrocarbons and more particularly to a process wherein the production of normally nongaseous hydrocarbons containing a plurality of double bonds is controlled.

Broadly this invention involves thetreatment of non-benzenoid hydrocarbons with an active halo gen in the presence of a substantial amount of an active metal halide catalyst material whereby the hydrocarbons are converted into normally nongaseous polyenes. I

Hitherto it has been known to halogenate hydrocarbons and subsequently dehydrohalogenate the halogenated hydrocarbons at relatively high temperatures to produce unsaturated hydrocarbons and hydrogen halide. Our process differs from these known processes in several respects. We have found that the presence of substantial amounts of aluminum halide prevents the normal halogenation reaction and induces the formation of liquid polyenes, Furthermore the degree of unsaturation and relative positions of the double bonds are controlled and directed by the aluminum halide. We have also found that the aluminum halide combines selectively with the polyenes to form an additional phase easily separable from unreacted hydrocarbons and by-products permit-.

' also differs from known processes in that the relative positions of the double bonds in the polyenes is such as to produce final products having diilerent characteristics than those prepared hitherto from the same hydrocarbons. The present process when operated at relatively low temperatures gives products of even better qualities, for example better color, odor and viscosity.

Several processes are also known wherein hydrocarbons are treated in the presence of an active metal halide and a halogen acid such as HCl. In these 'processes the product consists primarily of isomers, alkylates, polymers and the like. In our process the main products consist of polyenes such as dienes, trienes and mixtures thereof.

In our process it is essential that substantial quantities of an active metal halide, SllCh, as aluminum halide be present when the hydrocarbon is contacted with, the active halogen. The term active halogen as used in the present description and in the appended claims means chlorine and bromine. Obviously it is highly desirable to be able to control the degree of unsaturation as well as to obtain a more nearly even degree of unsaturation throughout the final product. It is also desirable to obtain a product in which a substantial part of the polyenes have conjugated double bonds since such products are more reactive and have desirable characteristics. The presence of the alun inumhalide when the hydrocarbon and active halogen are contacted directs the reaction so that such desirable products as detive character of our process. Therefore, the hy-' drocarbon feed to our process contains no more than about 20% and preferably less than 5% are-- matics. The feed is also substantially free from halogenated hydrocarbons since these not only tend to lower the selectivity of our process but alter the course of the reaction so that polyenes contaminated with halogen containing hydrocarbons are produced. Such halogenated hydrocarbons lack the exceptional stability to heat and to chemicals exhibited by the substantially halogen-free product normally obtained by our process.

It is an object of the present invention to provide a process for producing normally non-gaseous polyenes from non-benzenoid hydrocarbons.

A further object is to provide a process wherein the production of normally non-gaseous polyenes containing a plurality of double bonds is controlled.

A still further object is to provide a process in which non-benzenoid hydrocarbons are treated with aluminum halide or aluminum halide comlexes and an active halogen and in which the normal halogenation reaction is prevented.

Another object of the invention is to produce unsaturated products having characteristics substantially difierent from those of the products obtained by treating a hydrocarbon with aluminum halide and a halogen acid.

An additional object of the present invention is to produce hydrocarbon oils having good drying characteristics.

Another additional object of this invention is to produce highly unsaturated hydrocarbon polymers having rubber-like properties and which may be vulcanized. I j j A further object of this invention is to' provide a process whereby a maximum amount of polyenic material is obtained from a given amount of hydrocarbon and halogen consumed.

plex is capable of acquiring an increased hydrocarbon content it is desirable to treat such complex with the active halogen in the presence of Another object is to produce pure anhydrous hydrogen halide from the halogen.

Another object is to produce unsaturated prodnote which are substantially halogen free from less unsaturated hydrocarbons.

Another object-is to provide a process for treating hydrocarbons having a wide range of molecular weights.

In general any hydrocarbon such as the parafiins, olefins, naphthenes, mixtures and .combinations thereof are suitable starting materials for our process. The hydrocarbon feed is contacted at a temperature of from about -100 F. to about 300 F., preferably about -40 F. to about 250F. with a halogen, preferably chlorine.- in the presence of a substantial amount of an aluminum halide, preferably aluminum chloride. In general the mol ratio of metal halide to halogen consumed lies within the approximate range of 0.5 to 5 but it is preferred to use a mol ratio,- AlCla/Ch, of 1.5 to 3.0, while a mol ratio, AiCls to 012, of about 2 has been-found to give particularly good results. There is generally produced a small upper layer comprising unreacted hydrocarbons, polymerized or depolymerized hydrocarbons, isoparafiins, parafiins and minor amounts of chlorinated hydrocarbons and a more voluminous lower layer of a; heavy oily material which consists of aluminum chloride combined with polyenes. The aluminum chloride complex layer and the lighter hydrocarbonjayer usually separateon standing. The separation can be accelerated and rendered more complete by centrifuging and/or washing the complex layer with a light parafiinic naphtha. It is important that the two layers be carefully separated.

The complex layer which contains the polyene and the aluminum chloride, as well as lesser amounts of HCl is treated to liberate the polyenes. This can be accomplished by decomposing the complex with water, dilute alkali, alcohol, or the like to produce an oil layer and a. hydrolysis layer containing the products of the aluminum chloride.

The oil is a polyene having an average molecular weight above about 300. The unsaturation of our product can vary from an average of about 2 to 6 but usually and preferably between 2-3 double bonds per molecule. In general the product is substantially chlorine free containing no more than 5% and usually less than 3% C1. The yield is in excess of 0.9 lb. of polyene product per lb. of aluminum chloride or .its equivalent present in the complex.

It is not necessary to use pure AlCla in our process. There are available active metal halide complexes, such as aluminum chloride complexes from several known processes such as those used in the refining of petroleum, for example, isomerization, alkylation and polymerization and, the processes for combining hydrogen halides with oleiins to produce alkvl halides, which complexes are spent for the original process, but are nevertheless valuable as starting materials in our process. These spent aluminum chloride complexes are treated with an active halogen either alone or preferably in the presence of additional hydrocarbons. 1f the aluminum chloridecomadditional hydrocarbon in order to obtain higher yields of polyenes. It is possible to obtain much higher yields and superior products in this way than that which would normally be obtained from the spent unmodified aluminum chloride complexes coming directly from known refining processes.

In addition to treating normally liquid or gaseous hydrocarbons having molecular weights below about 400 with an active metal halide and an active halogen it is also possible to start with hydrocarbons having a high molecular weight of the order of 400 to 100,000 or higher, such as petroleum waxes and hydrocarbon polymers, such as propylene polymers, isobutylene polymers and the like. In each case, whether the starting material is unsaturated or not, the final product will contain additional unsaturation and if of sufiiciently high molecular weight will be rubberlike and capable of vulcanization.

The products obtained by the process described herein are particularly useful in the fields where drying oil, drying resins, polymeric materials,

' elastomers and the like are used. In the case of elastomers this process, affords a good means for obtaining a product which can be vulcanized.

ing oil give films very similar to vegetable drying oil films in physical characteristics but with superior chemical resistance.

A valuable by-product of our process is anhydrous HCl. This is obtained during the first stage and also during the decomposition of the complex. If this decomposition step is carried out using an alcohol such as ethyl or isoprcpyl alcohol, an especially high yield of anhydrous HCl is recovered as well as appreciable yields of the alkylhalides corresponding to the alcohol used. The HCl may be used in any of those processes where HCl serves as a catalyst promoter, such as in isomerization, alleviation and the like. The aqueous layer from the hydrolysis of the complex contains aluminum salts. By proper treatment valuable products can be obtained from this aqueous layer. For example, the hydrogen ion concentration can be altered by conventional means so as to bring about gelation. The resultant aluminum hydroxide gel on drying yields a particularly eilective activated alumina which is valuable for many uses. The addition of excess sodium sulfate followed by evaporation permits the recovery of soda alum which is also valuable for many purposes.

The polyene obtained by our process varies in color from a pale yellow to a deep red depending on the charging stock and conditions of opera-.

tion. Ingeneral low temperatures say 509 to 0 F. and light gaseous oleflns like ethylene, butenes, and especially propene give avery high grade, light colored and quick drying product.-

Darker oils can be decolorized by clay treating or by distillationunder reduced pressure or distillation with steam; In general the bulk of the. oil can be taken as an overhead cut at 400 F., 2 mm Hg. The overhead cut is light colored. The residue is dark colored and may vary from 5 to 20% of the charge.

Data relating to several examples of our process straight or branch chain hydrocarbon as distinguished from naphthenes and aromatics.

polyenes substantially free of halogen comprising treating acyclic hydrocarbons oi the class consisting 01' ethylene, butenes, propylene, liquid propylene polymers, liquid iso-butylene polymers, hex

Table Run No.

A B D E F G. H

Charge A1 1: 36 364 I 4 1m 29. R1 40 A101; complex From AlCh+ isooctane. AlCh complex 3.. 224. Active halogen 0hlorine. Cl) Ch Oh Cl, Ch Cl Hydrocarbon Commercial ommercial Isobutylene Petroleum Propylene Petroleum Propylene isooctane. isooctane. polymer hexane. heptane. lymer (about250 5 000 mol mol. wt.). wt.).

Hydrocarbon g 1314 ltxeess. 408 400 98'. 350 121. (Egg?!) Temperature, F 80 V a0 80 Reaction time, hrs 6.5.. 10.0-- H01 recovered Complex formed, g 064.4 531 Polycne Yield 1bs./1b./AlC-h.---- 1.45-.- 0.5" 2.9 1.0 2.0 2.5 1.8 0.5. Na 1.5090 1.5120 1.4878 1.5230 1.5047 0.6. D ng rate Good G Good Good Good Good Fair. Co or. Fair Goo Poor Good Poor" ood Poor. Percent C]: by weight 1.2.- 1.53-- Not detn. Not detn Not detn Not detn.. Not detn Moi. weight 320 377 14 850 do do Do. Iodine number About 150- 163 197 72 dn do Do. Average number 01 dou- 2.4- 2.2- 2.4. do do Do. ble bond/mo]. l I

Isobutylene polymers having molecular weights of .Irom 50,000 to 100,000 01' higher are obtained by treating liquid isoolefins, such as liquid isobutylene, in the presence of a Friedel-Crafts catalyst at a temperature of the order of -100 F. Whe 43 grams of the resulting isobutylene polymers 9. hexane solution are treated with 16% grams of aluminum chloride to which has been added grams of bromine and the whole mixture heated to about a temperature of 125 F. for two hours, a

complex is formed which on hydrolysis with alcohol, for example, yields a product having increased unsaturation and a molecular weight substantially the same as the initial polymer. The product shows no decrease in elasticity. The

anes, heptanes, and octanes with a free halogen selected from the group consisting of chlorine and bromine and an aluminum halide catalyst material under conditions for producing a complex, hydrolyzing the complex, and separating unsaturated elastic polymer maybe vulcanized with sulfur toiorm a harder more resistant material. Although the invention has been described b means of specific examples, modifications oi' the above-described process will be apparent to those skilled in the art. The present invention should not be limited by the examples but rather is to be defined by the scope of the appended claims.

We claim: 1. A process for producing .normally liquid a normally liquid polyene from the products of the hydrolysis.

2. A process for producing normally liquid -polyenes substantially free of chlorine comprising treating acyclic hydrocarbons of the class consisting of ethylene, butenes, propylene, liquid propylene polymers, liquid iso-butylene polymers, hexanes, heptanes, and octanes with chlorine