US2022616A - Chlorinating ethylene hydrocarbons - Google Patents

Description

Nov. 26, 19 35 M. BERLJNER CHLORINATING ETHYLENE HYDROCARBONS Filed May 18, 1934 INK EkM

Jig/er Ber/her INVENTOR 4);,- ATTORNEY Patented Nov. 26, 1935 cg ETHYLENE HYDRO- ABBONS Meyer Berliner, Edgemere, N. Y., assignor to The Texas Company, New York, N. Y., a corporation of Delaware Application May'1 8, 1934, Serial No. 726,256

7 Claims. (01. 260-162) This invention relates to the 'halogenation of hydrocarbons of the ethylene series and more particularly to a process of chlorinating ethylene hydrocarbons whereby the dichlor derivatives of 5 the hydrocarbons are produced.

My invention contemplates a method of chlorinating hydrocarbons of the ethylene series wherein hydrocarbons such as ethylene, propylene, butylene, and the like, are reacted with chlorine in the presence of high boiling chlorinated compounds such as the trichlor and tetrachlor derivatives of propane and butane, or mixtures of these compounds, whereby high yields of the dichlor derivatives of the ethylene hydrocarbons are obtained. The reaction mixture may then be freed from dissolved chlorine and the hydrochloric acid by a suitable procedure, after which the reaction mixture is subjected to a distillation step. By means of the distillation operation, the desired 20 dichlor derivatives are segregated as a separate fraction while the high boiling chlor derivatives are separated and recycled to the chlorination reaction.

The preparation of dichlor derivatives of ethyl-- 25 ene hydrocarbons has always presented considerable difficulty and numerous expedients have been proposed to overcome this. The most success apparently has been had by employing solvents which dissolve both the chlorine and the 30 hydrocarbons. In this connection, cognizance is had of U. S. Patent No. 1,231,123 issued to Benjamin T. Brooks and Dillon F. Smith. This patent discloses the preparation of dichlor derivatives of ethylene hydrocarbons by reacting these hydro- 3 carbons with chlorine in the presence of a mutual solvent. As mutual solvents the inventors propose chloroform, carbon tetrachloride, carbon disulfide tetrachlorethane, and dichlorinated ethylene hydrocarbons.

40 I have discovered that by employing the trichlor and tetrachlor derivatives of propane and butane, higher yields of the dichlor derivatives of the ethylene hydrocarbons can be obtained than are possible when using the mutual solvents dis- 45 closed by Brooks and Smith.

In the practice of my invention, I may employ basis of my invention is most effectively carried out by maintaining a body of one of the above 'solvents or any mixture of these, and passing thereintc chlorine and the ethylene hydrocarbons to be chlorinated. When conducted in this way, 6 the reaction is quite rapid and smooth, and a high percentage of the dichlor derivatives is formed. Although the reaction is advantageously carried out at a low temperature such as of the order of 0., lower or higher temperatures may be used, 1 the choice of the proper temperature being de pendent upon the type or types of ethylene hydrocarbons undergoing reaction. The reaction is advantageously carried out under a pressure in the neighborhood of atmospheric. However, in certain applications of the invention, it may be desirable to use higher pressures which may be as high as 200 pounds per square inch or higher.

The above described invention has been incorporated in a chlorination procedure which will 29 be readily understood by reference to the accompanying drawing which shows in diagrammatic sectional elevation a suitable apparatus for emciently carrying out the process.

In the figure, the numeral til refers to a storage for the solvent. This vessel is connected through the line H and the valve it with the inlet side of the pump 03. This pump is connected by the line I4 controlled by the automatic float-controlled valve l5 with the spray it which is supported in an upper portion of the reaction vessel l'l.

The numeral 2t refers to a storage tank r'cr ethylene hydrocarbons which is connected through'the line 2! and the valves 22 and 25% with the inlet side of the pump M. This pump is connected by the line 2% controlled by the valve 29 with the spray 30 which is situated ata low'erpoint in the reaction chamber ii. A bypass line 25 controlled by the valve 26 connects line 2! at a point intermediate the valves it and 23 with the line 28.

pressure used in the process and also constructed of such material as is proof against the corrosive toy-products that are formed in the course of the reaction. The vessel is provided with cooling coils 32 for maintaining the reaction mixture at the proper temperature and with insulation it. to prevent absorption of heat from the surrounding atmosphere. The vessel is also provided at a point below the spray IS with a bed 33 of distributing material such as Raschig rings, tile, pumice stone, or the like, supported on a foram- 5 e This iced acts both as a distribr the solvent which is injected and also serves to minimise the cuts by the formation of mists. The top oi 61 e vessel is provided with a vapor drawofl line 3? controlled by the valve 31 which connects the vessel with a storage provision or an apparatus ior recovering any unreacted ethylene hydrocarbons. There is inserted into a lower point of the vessel spray it whidh is connected through the valve with a source or supply of chlorine. There provided at a point immediately above the spray a bed to of distributing material such as Raschig rings, tile, pumice, or the like which is supported on a ioraminous plate ti.

' This bed which may be of varying depth serves to facilitate the interaction of the reactants.

The lowermost point of the reaction vessel ill is connected by the line 53 controlled by the valve M with the pump lii which discharges through the line to and the valve ll into the top of the washer to. The washer comprises essentially a vessel provided with a mechanical agitating device 49. It is connected through the line to controlled by the valvev with the discharge side of the pump 52. The inlet side of this pump is in turn connected through the line 53 and the valve 54 with the storage tank 55 for wash liquid. The bottom of the washer is provided with a discharge line 56 controlled by the valve 57 which connects it with the settling chamber 58. This chamber is provided at its uppermost point with a discharge line 59 controlled by the valve 60 which leads to a sump, while the bottom of the vessel discharges through the line BI and the automatic float-controlled valve 62 into the intake side of the pump 63. The discharge side of this pump is connected through the line 64 and the valve 55 with the drying chamber 86. This drying chamber is a vessel containing drying chemlcals such as anhydrous calcium chloride, anhydrous copper sulfate or any other material which readily absorbs water and which does not detrimentally affect the products of the chlorination. The drier is connected by the line 61 controlled by the valve 68 with the. heating coil 69 situated in the heater l0.

In order to permit of the by-passing of the washing and drying apparatus, there is provided the by-pass line 12 controlled by the valve 13 which connects the line 46 at a. point intermediate the pump 45 and the valve 41 with the line 61 intermediate the valve 68 and the inlet to the heating coil 69.

The heater consists essentially of theheating coil 69 and 9. containing vessel through which a heating medium such as high pressure hot oil or the like may be circulated. The outlet of the heating coil 89 isconnected through the line and the expansion valve 16 with a lower point of the fractio'nating tower 11. This tower is advantageously provided at an upper point of its structure :ith a cooling coil I8 which serves to provide reflux for the tractionating operation. The top of the tower is connected through the line I9 controlled by the valve 80 with the coil 8| of the condenser 82. The outlet side of this condenser discharges through the line 83 controlled by the valve 84 to a suitable storage. The bottom of the Iractionating tower is connected by the line 8i controlled by the valve 81 through the pump 88 with the storage tank III.

In a typical operation of the present process, an ethylene hydrocarbon or a mixture of ethylene hydrocarbons is drawn from the storage tank assassin and delivered under its own pressure or bypurnp pressure to the line '28 and thence to the spray situated within the reaction chamber iii. There is simultaneously delivered into the upper portion of the reaction chamber through 5 the spray it a quantity of one of the previously described solvents which may consist either of a. trichlor or tetracblor derivative of propane or butane or any mixture of these derivatives. The

quantity of solvent supplied is automatically con- 10 trolled by means of the float-controlled valve l5. There is also injected into the reaction vessel through the spray it a: measured and controlled quantity of chlorine.

The chlorine and ethylene hydrocarbon or by- 15 drocarbons are mutually dissolved by the solvent and a rapid reaction resulting in the formation of the dichlor derivatives of the ethylene hydrocarbon or hydrocarbons occurs.

The temperature maintained with the reaction chamber l'l' must be kept within closely controlled limits in order to effect the highest possible conversion of the ethylene hydrocarbons into dichlor derivatives. Although no specific temperature can be given since the same is dependent on the pressures used in carrying out the reaction, as well as on the types of ethylene hydrocarbons undergoing chlorination, in most cases temperatures below 60 F. may be employed with advantage.

The products of the reaction become dissolved in thesolvent and this solution is continuously withdrawn from the bottom of the reaction chambe:- through the line 43 and delivered to the pump 45 which delivers the same either directly to the heater 10 or else through the washing and drying apparatus. In the latter case, the solution of dichlor derivatives in solvent is delivered under a suitable pressure into the washing chamber 48 wherein the solution is washed with water or an aqueous alkaline solution in order to free it from free chlorine or hydrochloric acid. This is accomplished by thoroughly agitating the solvent solution of dichlor derivatives with the wash liquid and then delivering the mixture to the separatory chamber 58 wherein the dichlor deriva-- tives in solvent are caused to separate from the spent wash liquid. The latter is drawn on and passed to a sump while the former are charged by means of the pump 63 through the drying chamber wherein any remaining water is removed by the hygroscopic drying materialscontained therein. The dried solution of dichlor derivatives in solvent is then delivered to the coil 6! of the heater 10 wherein it is heated to an elevated temperature above the vaporization temperature of the dichlor derivatives. The heated solution is then passed through the expansion valve IO into a. lower point of the fractionating tower 11 where the dichlor derivatives are separated from the solvent liquid. The former are vaporized and are delivered from the top of the tower to the condenser 82 where they are condensed. The solvent liquid, on the other hand, collect: as a pool at the bottom of the fractionatlng tower I1 from which it is drawn through the line 80 by means or the pump 88 and returned to the solvent storage tank l0.

Comparative experiments have been conducted on the preparation of dichlor derivatives of mixed ethylene hydrocarbons and comprising particularly ethylene, propylene and butylene. These hydrocarbons were reacted with chlorine inthe presence of dlflerent solvents. The solvent: em- 7 ployed were:

ace-2,016

1. The dichlorides of the hydrocarbons formed by the chlorination of the hydrocarbons used in the experiments.

2. Symmetrical tetrachlorethane.

3. A mixture of trichlor and tetrachlor propanes and butanes having a boiling range of approximately 130" to 205 C.

The procedure that was followed consisted in maintaining a body of the particular Solvents at a temperature of 41 F. and introducing thereinto chlorine and the mixed ethylene hydrocarbons. The controlling prime variables were maintained substantially uniform and constant. These included the temperatures, pressures and quantity of reagents delivered to the reaction zone in a unit of time. The solvents containing the dichlor derivatives were then subjected to a distillation operation and the dichlor derivatives separated as distinct fractions. The yields obtained with the solvents set forth above were as follows:

me in percent of theoretical Solvent Olefin Chlorine basis basis l. Dicblorldes of mixed ethylene hydrocarbOIB 54.1 64.8 2. Symmetrical tetrachlorethano 54.9 64. l

3. Mixed trichlor and tetrachior propanes and bntanes 68. 6 76. 8

These results indicate that the solvents which I' have discovered permit of increased yields of ethylene hydrocarbon dichlorides over the solvents proposed in the past.

Although I have described this invention in connection with the preparation of dichlor derivatives of ethylene hydrocarbons present in high concentrations, the reaction may nevertheless be advantageously used in dichlorinating ethylene' of the invention, as hereinbefore set forth, may 1 be made without departing from the spirit and "scope thereof, and therefore only such limitations 1. A method of preparing dichlor derivatives of ethylene hydrocarbons which comprises reacting 5 the ethylene hydrocarbons with chlorine in the,

presence oi amixture of trichlor and tetrachlor propanes and trichlor and tetrachlor butanes.

2. The method of preparing dichlor derivatives of ethylene hydrocarbons which comprises main- 1 'taining a body of a mixture oi trichlor and tetrachlor propanes and trichlor and tetrachlor'butones, and passing thereinto astream of chlorine and a-stream oi the ethylene hydrocarbons.

3. The method of preparing dichlor derivatives 15 of ethylene hydrocarbons which comprises reacting the ethylene hydrocarbons with chlorine in the presence of a mixture of trichlor and tetrachlor propanes and trichlor and tetrachlor butanes at a temperature of in the neighborhoodoi 5 C. 20

4. The method of preparing dichlor derivatives of ethylene hydrocarbons which comprises reacting the ethylene hydrocarbons with chlorine in the presence of a mixture of trichlor and tetrachlor propanes and trichlor and tetrachlor bu- 25 tanes and under superatmospheric pressure.

5. The method of preparing the dichlor derivatives of ethylene hydrocarbons which comprisesreacting the ethylene hydrocarbons with chlorine in the presence of a solvent consisting of trichlor 30 and tetrachlor propanes and trichlor and tetrachlor butanes whereby the so-iormed dichlor derivatives become dissolved in the solvent together with unreacted chlorine and hydrochloric acid, washing the reaction product to remove the chlo- 35 rine and hydrochloric acid and finally separating the dichlor derivatives. from the solvent by distillation, and'returnlng the solvent to thereaction.

6. A- method of preparing dichlor derivatives of ethylene hydrocarbons which comprises react- 4'0 ing the ethylene hydrocarbons with chlorine in the presence of a solvent selected from the group consisting of trichlorpropane, trichlorbutane, tetrachlorpropane, and tetrachlorbutane.

7. A method 01 preparing dichlor derivatives of 45 solvents selected from the group consisting of triclorpropane, trichlorbutane, tetrachlorpropane,

and tetrachlorbutane.

MEYER IBERIINER.

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