CS209349B1 - Process for preparing tetrachloroalkenes - Google Patents

Abstract

The invention relates to a method for preparing tetrachloroalkenes of the general formula R R x-ch-c=ch-ch2z where R is a hydrogen atom or a methyl group, X is a chlorine atom and Z is a trichloromethyl group or X is a trichloromethyl group and Z is a chlorine atom, by catalytic radical addition of carbon tetrachloride to acyclic 1,3-dienes of the general formula R R I I ch=c-ch=ch2 where R has the above-mentioned meaning. The production process consists in heating the starting reactants in the above-mentioned ratios to a temperature of 75 to 170 °C with stirring at normal or up to 2.0 MPa increased pressure in an atmosphere of an inert gas, such as nitrogen, argon or helium. The process is explained in more detail by two examples.

Description

The present invention provides a process for the preparation of tetrachloralkenes. The application relates to (PV 8879-79), MS. No. 2 () 9 347 _f concerning a process for the preparation of polychlorinated organic compounds.

A process for preparing tetrachloralkenes of the general formula

R R

II

X-CH-G = CH-CH ₂ Z (I) wherein R is hydrogen or methyl, X is chlorine and Z is trichloromethyl or X is trichloromethyl and Z is chlorine, by catalytic addition of carbon tetrachloride to acyclic 1,3-dienes general formula,

R R

II

CH = C-CH = CH ₂ (II) wherein R is as defined above is generally known. Tetrachloroalkenes, which are valuable organic products or intermediates, are thus available in a one-step process. Iron, ferrous or copper (I) chloride can be used to catalyze these reactions (Journal of the Chemical Society, 1963, 1887) in the presence of secondary amines and solvents such as low aliphatic alcohols, acetonitrile or chloroform; The ruthenium complex is also effective as a catalyst (Chemistry betters 1978, 115).

We have now found that the addition of carbon tetrachloride to the acyclic 1,3-dienes of formula II leading to the tetrachloroalkenes of formula I can be catalysed with high efficiency by readily available oxides of certain metals in conjunction with secondary or tertiary amines or their hydrochlorides and tertiary phosphines.

♦

The present invention provides a process for the preparation of the tetrachloroalkenes of formula (I) wherein R and X are as defined above by catalytic addition of carbon tetrachloride to the acyclic 1,3-dienes of formula (II) wherein R is as defined above, from 1 to 50 moles of carbon tetrachloride. 1 mol of cuprous oxide or cuprous oxide or iron oxide, and from 0.005 to 0.2 moles of secondary amine or tertiary amine or their hydrochlorides or tertiary phosphine, or from 2 to 40 moles of a C 1 -C 4 -aliphatic alcohol or acetonitrile as solvent, heated to 75-170 ° C with stirring under normal or up to 20 bar of elevated pressure in an inert gas atmosphere such as nitrogen, argon or helium.

The acyclic 1,3-diene of the formula II according to the invention can be butadiene, 1,3-pentadiene or isoprene. The insulation yields of the tetrachloralkenes of the formula I prepared according to the invention are at least 73%. ¹

The preparation of the tetrachloroalkenes of the formula I can be carried out preferably using a molar ratio of 2 to 20 moles of carbon tetrachloride per 1 mol of the acyclic diene of the formula II and at a temperature of 100 to 140 ° C.

The secondary amine or tertiary amine may be, for example, diethylamine, diisopropylamine or pyridine and the tertiary phosphine triphenylphosphine.

The metal oxides, in conjunction with the secondary or tertiary amine or their hydrochlorides or tertiary phosphine, or in conjunction with the C 1 -C 4 -aliphatic alcohol or acetonitrile as initiators of the preparation of the tetrachloralkenes of the formula I have advantages over the previously known initiators. lower price. The organic peroxide compounds usually used as initiators in the free-radical, editing reactions in this case provide no more than 5% tetrachloralkenes (Chemistry Letters 1978, 115).

The examples below describe the process of preparing the tetrachloralkenes of the present invention without limiting or limiting its scope.

Example 1

Mixture containing 30.8 g (0.2 mol) of carbon tetrachloride, 1.08 g (0.02 mol) of 1,3-butadiene, 0.016 g (0.2 mmol) of cupric oxide and 0.030 g (0.4 mmol) The diethylamine is heated under a nitrogen atmosphere in a vortexed and sealed glass vial at 100 ° C for 12 hours. After this time, when virtually all 1,3-butadiene had reacted, the reaction mixture was cooled to room temperature, excess tetrachloroethane was recovered by distillation of the mixture at normal pressure, and the residue was distilled under reduced pressure from a collar flask to give 3.24 g. cis-trans 1,1,1,5-tetrachloropent-3-ene having a boiling point of 80 ° C / 1.6 kPa in a yield of 78%. Elemental analysis (for CgHgCl ^ (207.91) calculated: 28.89% C 2.91% H Found: 29.01% C, 2.91% H) IR spectrum (3040 cm-CH ^b) and NMR spectrum (4.10 d, 3.5 d, 3.4 d, 5.95 s, 5.9 + 5.8 m, ppm) confirm the stated composition of the product.

AND

Example 2

Mixture containing 30.8 g (0.2 mol) of carbon tetrachloride, 0.68 g (0.01 mol) of isoprene, 0.0079 g (0.1 mmol) of cupric oxide and 0.0146 g (0.2 mmol) of diethylamine was heated in a vibration stirred and sealed glass vial at 120 ° C for 8 hours under nitrogen atmosphere. After this time, when virtually all isoprene has reacted, the reaction mixture is cooled to room temperature, treated as in Example 1 to give 1.6208 g of tetrachloralkene (73% yield on isoprene charged), boiling 92-93 ° C. 1.6 kPa, the composition of which corresponds to the elementary analysis by the empirical formula CGH _g Cl ₄ and which by NMR spectra of the isomeric mixture of 1,1,1,5-tetrachloro-3-methylpent-3-ene and 1, l, l, 5 -tetrachloro-4-methylpent-3-ene.

Claims (5)

A process for the preparation of tetrachloralkenes of the general formula R R, II · - .. ·· X-CH-C = CH-CH ₂ Z '(I) wherein R is hydrogen or methyl, X is chlorine and Z is trichloromethyl or X is trichloromethyl and Z is chlorine, by catalytic radical addition of carbon tetrachloride to the acyclic 1 3-dienes of general formula R R I I. CH = C-CH = CH ₂ (II) wherein R is as defined above, characterized in that the reaction mixture contains 1 to 50 moles per mole of the acyclic 1,3-diene of formula II, wherein R is as defined above tetrachloro-methane, 0.005 to 0.1 moles of cuprous oxide or cuprous oxide or iron oxide, and 0.005 to 0.2 moles of secondary amine or tertiary amine or their hydrochlorides, or tertiary phosphine, or 2 to 40 moles of C 1 -C 3 -aliphatic of alcohol or acetonitrile is heated to 75-170 ° C with stirring under normal or up to 20 bar of elevated pressure in an inert gas atmosphere such as nitrogen, argon or helium. 2. Process according to claim 1, characterized in that the reaction mixture contains 2 to 20 moles of carbon tetrachloride per 1 mol of acyclic 1,3-diene of the formula II. 3. A process according to claim 1 wherein the secondary amine or tertiary amine is diethylamine, diisopropylamine or pyridine. 4. A process according to claim 1 wherein the tertiary phosphine is triphenylphosphine. 5. The process of claim 1, wherein the reaction mixture is heated to a temperature of 100-140 ° C.