US3028439A - Process for the production of 1, 2, 3-trichloropropene - Google Patents

Description

United States Patent Oiiice 3,fi28,43 Fatented Apr. 3, 1962 3,028,439 PROCESS FOR THE PRODUCTION OF 1,2,3-TRECHL'9ROPROPENE Louis F. Theiiing, J23, Charleston, and Joseph F. Lacount, South Charleston, W. Va., assignors to Union Carbide Corporation, a corporation of New York No Drawing. Filed Mar. 23, 1960, fier. No. 16,914 Claims. (Cl. 260 454) This invention relates to a novel method for the production of 1,2,3-trichloropropene.

More specifically, the invention is concerned with the dehydrochlorination of 1,2,2,3-tetrachloropropane to obtain 1,2,3-trichloropropene.

The object of this invention is to provide an eflicient economical process by which 1.2,2,3-tetrachloropropane can be converted to 1,2,3-trichloropropene.

The above object is accomplished by conducting the dehydrochlorination in the presence of an emulsifying agent.

1,2,3-trichloropropene is not a new compound. It is wel known in the art. The method of making the above compound by dehydrochlorination of 1,2,253-tetrachloropropane is also known in the art.

The methods previously employed for dehydrochlorination of l,2,2,3-tetrachloropropane included the use of aqueous sodiumhydroxide, the use of aqueous sodium hydroxide and methanol, the use of sodium hydroxide and dioxane, and the use of methylethylpyridine residues.

However, these rnethods of effecting the reaction had at least two serious disadvantages. Poor conversion of 1,2,2,3-tetrachloropropane and/or low efficiency to the trichloropropene were obtained. Also, the crude reac tion product frequently contained large amounts of impurities which could not be easily removed by refining.

Surprisingly, the above disadvantages have been found to be obviated when the dehydrochlorination is conducted in the presence of an emulsifying agent. The reaction proceeds at a rapid rate and the conversion of the 1,2,2,3-tetrachloropropane to 1,2,3-trichloropropene is higher than any of the known prior art methods. Additionally, the crude reaction product can be refined with comparative ease.

The following table illustrates the comparison of the prior art methods with the method of the instant inventicn.

TABLE I Preparation of 1,2,3TrichloropropenePr0ducti0n 401 is tetrachloropropane and 30? is trichloropropene.

1 Tctrachloropropane and sodium hydroxide were refluxed for six hours.

A ten percent excess of equal weights of 50 percent sodium hydroxide and methanol fed to tetrachloropropane over a two-hour period.

4 Tetrachloropropane was fed to 400 methylethylpyridine residues (catalyst) at the rate of 487 grams per hour per liter of methylethylpyridine residue.

A ten percent excess of equal weights of 50 percent sodium hydroxide and dioxane added to tetrachloropropane and refluxed for five hours.

Aqueous 20 percent sodium hydroxide fed to tetrachlorcpropane containing one weight percent Tcrgitol, at the rate of 140 g. per hour per liter of tetrachloropropane and allowed to reflux for one hour.

It can be seen that the use of an emulsifying agent gives efiiciencies which are surprisingly better than the previously known methods.

Although a conventional emulsifying agent having a molecular weight in the range of 264 to 4000 can be used in the instant process, the preferred emulsifying agent is a Tergitol. Tergitol is a trademark of Union Carbide Chemicals Company for its surface active agents. There are two general types of these agents, anionic and nonionic. The anionic type are sulfates or phosphates of the C to C alcohols. The nonionics are ethylene oxide adducts of nonyl phenol, 2,6,8-trimethyl-4-nonanol, and a butanol and ethylene oxide-propylene oxide adduct. The molecular Weight range of the nonyl phenol adducts is 396-4100, that of the nonanol adduct is about 264 and that of the butanol adduct is from 2820 to 3414.

The term nonyl phenol is intended to mean a mixture of alkylated phenols whose substituents on the aromatic ring are predominately mixed ortho and para-isomers. The alkyl side chain. of which is a mixture of branched isomers containing a varying number of carbon atoms (C C C with the C predominating.

A particularly preferred class of the above surface active agents are those having a molecular weight range of 525-975.

The amount of emulsifying agent used is about 0.1 to about 10 percent by weight based on the 1,2,2,3-tetrachloropropane. The preferred range is 0.5 to 5 weight percent.

The dehydrochlorinating agents employed are the alkali metal and the alkaline earth metal hydroxides. Specific examples include lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide and strontium hydroxide. The preferred reagent. is sodium hydroxide.

The temperature at which the reaction is conducted is not narrowly critical. The preferred range is from about to C. at atmospheric pressure, although the kettle temperature may vary during the reaction. In

a preferred embodiment of the invention, not only is the kettle temperature controlled, but the vapor temperature is alsoregulated. At atmospheric pressure, the vapor temperature is maintained from about 93 to about 95 C. during reflux. It has been found that this range gives the highest efficiency. 1

The reaction can be conducted by mixing all the reagents together and refluxing, by adding the l,2.2,3-tet1'achloropropane to refluxing aqueous hydroxide containing the emulsifying agent or by the gradual addition of the hydroxide to a mixture of the emulsifying agent and the 1,2,2,3-tetrachloropropane. The latter method is the preferred one. In this method, the hydroxide is added in the range of 001-05 mole per hour per mole of 1.2.2.3- tetrachloropropane. The preferred range is 0.05 to 0.1 mole per hour.

The concentration of the aqueous hydroxide solution employed is not narrowly critical. The preferred concentration is from about 20 to about 50 percent by weight.

In order to obtain the maximum efiiciency to 1,2,3- trichloropropene it is desirable to remove the crude product as rapidly as it is formed. This is done to prevent the dehydrochlorination of the 1,2,3-trichloropropene to form 1,3-dichloropropyne. This removal can be accomplished by any conventional manner such as distillation.

The following examples are illustrative of the instant invention.

EXAMPLE I 625 grams of 1,2,2,3-tetrachloropropane and 6.3 grams of Tergitol NP-35 (an ethylene oxide adduct of nonyl phenol with a molecular weight of about 880) was charged to a 2-liter kettle equipped with a sealed mechanical stirrer, therm-owell, and sodium hydroxide feed tank. The kettle was placed on a IS-theoretical plate column which was equipped with a decanting still head.

and receiver system. The receiver system was vented through cold traps.

The kettle contents were heated to 120 C. with s irring and aqueous 20 percent sodium hydroxide fed at the rate of 140 grams per hour per liter of tetrachloropropane. After refluxing for an hour, 1,2,3-trichloropropene was removed as lower layer of the water-trichloropropen-e azeotrope. The vapor temperature ranged from 93-94 C. during the reaction. The mole ratio of tetrachloropropane to total sodium hydroxide fed Was about 1:1.

The crude 1,2,3-trichloropropene was refined on a 15- theoretical plate column. Cisand transisomers or produced in the process in almost equal amounts. The trichloropropeue fraction was collected from 775-91 C. at 120 mm. Hg. Specific gravity of the fraction was 1.41 at 26/156" C. Conversion of tetrachloropropane Was 63.2 percent and efiiciency to trichloropropene was 86.5 percent based on tetrachloropropane.

EXAMPLE II 418 grams of 1,2,2,3-tetrachlorop-ropane, 195 grains of 50 percent aqueous sodium hydroxide, and 19 grams of Tergitol E-68 (Tergitol Ni -35 which has been etherilied to remove the active hydrogen. The hydrogen has been replaced with an ethyl group to make a causticstable surface active agent) were charged to the apparatus described in Example I and heated to 130 C. for eight hours. 200 grams of water was added to the still kettle and the organic layer removed as lower layer of the azeotrope. Conversion of tetrachloropropane was 72 percent and efficiency to 1,2,3-trichlropropene was 76 percent based on tetrachloropropane.

EXAMPLE III 1226 grams of 1,2,2,3-tetrachloroprop ane and 13 grams of Tergitol NP-27 (an ethylene oxide adduct of nonyl phenol with a molecular Weight of about 528) was charged to the apparatus described in Example I and heated to 140 C. Aqueous 20 percent sodium hydroxide Was fed at 155 grams per hour per liter of tetrachloropropane charged. Mole ratio of tetrachloropropane to total sodium hydroxide fed was about 1:1. Crude 1,2,3-t1ichloropropene was removed as lower layer of water-trichloropropene azcotrope and refined as in Example 1. Conversion of tetrachioropropane was 66 percent and eificiency to trichloropropene was 83 percent based on tetrachloropropane.

We claim:

1. In the dehydrochlorinatlon of 1,2,2,3-tetrachloropropane to obtain 1,2,3-trichloropropene in the presence of an aqueous solution of hydroxides selected from the group consisting of alkali metal hydroxides and alkaline earth metal hydroxides, the improvement which comprises carrying out said dehydro-chlorination in the presence of an emulsifying agent having a molecular weight of 264 to 4900 said emulsifying agent being selected from the group consisting of sulfates of alcohols which have from 8 to 17 carbon atoms, phosphates of alcohols which have from 8 to 17 carbon atoms, ethylene oxide adducts of nonyl phenol, ethylene oxide adducts of 2,6,8- trirnethyl-4-nonanol and ethylene oxide-propylene oxide adducts of butanol.

2. The process of claim 1 in which the emulsifying agent is an ethylene oxide adduct of nonyl phenol having a molecular Weight from 396-1100.

3. The process of claim 1 in which the emulsifying agent is present in the range of 0.1 to 10 percent by We'ght, based on the l,2,2,3-tetrachloropropane.

4. The process of claim 1 in which the emulsifying agent is present in the range of 0.5 to 5 percent by Weight, based on the 1,2,2,3-tetrachloroprop-ane.

5. The process for the production of 1,2,3-trichloropropene which comprises gradually adding an aqueous solution of sodium hydroxide to a mixture of 1,2,2,3- tetrachloropropane and a nonyl phenol adduct of ethylene oxide having a molecular weight of 396-1100 maintained at a temperature of -14-S C., said adduct being present in a concentration of 0.1 to 10 percent by Weight based on the 1,2,2,3-tetrachloropropane maintaining the vapor temperature at 9395 C. and removing the 1,2,3- trichloropropene formed.

References Clted in the file of this patent UNITED STATES PATENTS

Claims (1)

1. IN THE DEHYDROCHLORINATION OF 1,2,2,3-TETRACHLOROPROPANE TO OBTAIN 1,2,3-TRICHLOROPROPENE IN THE PRESENCE OF AN AQUEOUS SOLUTION OF HYDROXIDES SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL HYDROXIDES AND ALKALINE EARTH METAL HYDROXIDES, THE IMPROVEMENT WHICH COMPRISES CARRYING OUT SAID DEHYDROCHLORINATION IN THE PRESENCE OF AN EMULSIFYING AGENT HAVING A MOLECULAR WEIGHT OF 264 TO 4000 SAID EMULSIFYING AGENT BEING SELECTED FROM THE GROUP CONSISTING OF SULFATES OF ALCOHOLS WHICH HAVE FROM 8 TO 17 CARBON ATOMS, PHOSPHATES OF ALCOHOLS WHICH HAVE FROM 8 TO 17 CARBON ATOMS, ETHYLENE OXIDE ADDUCTS OF NONYL PHENOL, ETHYLENE OXIDE ADDUCTS OF 2,6,8TRIMETHYL-4-NONANOL AND ETHYLENE OXIDE-PROPYLENE OXIDE ADDUCTS OF BUTANOL.