DE1568007A1 - Process for the preparation of 1,1,2,2-tetrachloro-1,2-bis (p-chlorophenyl) ethane - Google Patents

Description

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Dr. F. Zrry ' ; ·>. . ^; "'*. .A: sniann

D: ·, R. '' - ■. "^ οη.ΌΓ
Dipi .. "! ■ · / .. f.! ] -: ■ '. Shaver

Paleni'an envelope 91 ° 9 / ΠΓ 1 ^ ⁼

Munich 2, Bräuhaussfra ^ e 4 / lli " ^Ιο '^

Process for the production of 1,1,2,2-tetrachloro-l, 2-bis- (p-

chlorophenyl) ethane

The present invention relates to a process for the production of l, l, 2,2-tetrachloro-l, 2-bis ~ (p-chlorophenyl) -ethane, which. hereinafter referred to briefly as "hexachlorodibenzyl".

One of the most common compounds currently in use is this 1,1, l-trichloro-2,2-bis- (p-chlorophenyl) -ethane, which generally known as DDT. DDT is a remarkably active contact insecticide known and used around the world will.

It was found that there were many other chemical compounds related to and derived from DDT are valuable in some areas of application. Among these substances, "Hexachlorodibenzyl" was used in laboratory quantities a difficult to control relocation process from chlorinated DDT [1,1,1,2-tetrachloro-2,2-bis (p-chlorophenyl) ethane; manufactured. Like W, L. Walton in Journ of American Chem. Society _ £ 5, S 1544/5 (1947), there is one such method E.g. that 15 g of chlorinated DDT are mixed with 5 mg of anhydrous .. i'errichlorid melts together for 15 seconds and then immediately cool the reaction vessel in an ice-water bath.

This conversion is strongly exothermic and what makes one HäiJjor heated for more than 15 seconds ^ much gaseous Caior-

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hydrogen with the formation of a dark-colored, viscous mixture of keuccion, from which no kexachiordibenzyi isolated; wercc-n can. This Walton method can only be used in extremely small:.; l-scale be performed; Try this procedure: ulc ^ "übooren Carrying out fabric lines results in explosive disintegration of the tongue had. For this reason, the Walton method is only of interest to the laboratory.

The subject of the present invention is a new, easily controllable process for the production of hexachlorodibenzyl by molecular storage from chlorinated DDT. This new process can reduce the formation of undesirable by-products. v / ground and practically 100% yields of hexachiorcibonzyl can be achieved. The inventive method ei _o:; ec for the production of Hexachlordiben.:yis in larger: u ^ Mass, and Benue ^ iC only technical chlorinated DDT as AusgangsnateriaL because _-ir. that which other substances in variable ..engen encnL'lj, primarily unchlorinated ο, ρ'-DDT, without the good yield; affect the desired end product.

The method according to the invention is characterized in that a solution of 1,1, L, 2-tetrachloro-2,2-bis (p-chlorophenyl) ethyne (chlorinated DDi '') Lr. an organic ir.ercan 'heated .fsungsmittel and in the presence of a Lewis acid. • lolekülu.T.lagcrun-S catalyst for 0.25 to 3 hours at between 100-150 Temperacuren ^ü C.

You can use impure, so-called technical, as a starting material Use chlorinated DDT.

The following example is intended to use the method according to the invention explain in more detail, parts and percentages relate to ^ -t_- parts by weight and percentages by weight, and the temperatures sinu i; i Degrees Celsius.

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example

A mixture of 389 parts of technical grade chlorinated DDT (purity about 7.0%), 150 parts of monochlorobenzene and 2 parts of anhydrous Ferric chloride is heated to 110-115 ° and for one hour leave at this temperature. Then, after the reaction mixture has cooled to 70 °, 400 parts of ethanol are added, the mixture cooled to room temperature and filtered. The filter cake obtained is twice using 200 parts of ethanol washed and then dried in vacuo at about 110 °.

Calculated on the weight of the impure, 70 / proprietary technical chlorinated DDT (the other components consist of 18% ο, ρ'-DDT, 4% dehydrochlorinated ο, ρ ¹ - and ρ, ρ'-DDT, 3 % ρ, ρ ' -DDT and 5 % other substances), the yield of aexachlordibenzyl 6b is 70%, but calculated on the weight of the pure p, p'-isomer of chlorinated DDT, which is contained in the technical material, the yield is over 98 %. The llexachlorodibenzyl obtained had a purity of 99 % and a melting point of 190-195 °.

The reaction taking place in the process according to the invention takes place according to the following equation:

Solvent + Katalyt ^{Ci C1} _

^ V-Cl > ci-ACC.-A 'VCi

^{v == /} 100 - 150 ° ^ = * '. · ^

ui ul

"chlorinated DDT" "..exachiorcibenzyl"

Mol.wt. 388.95 Mcl. _fc ew. 38b, V5

The rearrangement reaction according to the curve can be carried out ^{at temperatures between IOC and 150 ° C.} To Zr ^ ie ^ u: -._; For optimum results in terms of product purity and yield, reaction temperatures of about HC-115 "are preferred. In any case, temperatures above -150" should be avoided.

One can use various organic solvents for the reaction use, provided that they: -., behave inertly in the course of the process and have boiling points above 100 ". Particularly suitable solvents are xitrobenzene, chlorine, -benzene and mixtures thereof with benzene, the benzci content being

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, can be approximately 25-50%. There were mixtures of the former Solvents with 25%, 35%, 40% and 50% by weight benzene

" used. Such mixtures are often particularly favorable because it when refluxing the more volatile component, it is possible to keep the reaction temperature in the preferred range, e.g. to hold between 110 and 115 °.

Instead of the ferric chloride in the above example, other Lewis acid can also be used as rearrangement catalysts, such as anhydrous aluminum chloride, anhydrous zinc chloride, anhydrous tin (4) chloride, anhydrous titanium tetrachloride. While ferric chloride is the preferred catalyst, very good yields can also be achieved, for example, with anhydrous aluminum chloride. If, for example, in the above example the iron chloride catalyst is replaced by 2.5 parts or by 5 parts of anhydrous aluminum chloride, the corresponding yields are 65.4 % and 69.5%, calculated on the impure technical grade chlorinated DDT.

These Lewis acids are used in small, i.e. catalytically effective amounts between O ,! and 2 7o and preferably between 0.5 and 1%, based on the amount of technical chlorinated used DDT applied.

The implementation time may vary depending on the selected temperature, etc. vary slightly, but 0.25 to 3 hours is the desired length of time.

909885/1664 BAD

Claims (4)

Claims 1. A process for the preparation of 1,1,2,2-tetrachloro-l _} 2-bis (pchlorphenyl) ethane, characterized in that a solution of l, l, l, 2-tetrachloro-2,2- bis (p-chlorophenyl) -ethane heated in an inert organic solvent and in the presence of a Lewis acid as a molecular rearrangement catalyst for a period of about 0.25 to 3 hours at a temperature between 100 and 150 ⁰ C. 2. The method according to claim 1, characterized in that one as a rearrangement catalyst ferric chloride, aluminum chloride, zinc chloride, Tin (4) chloride or titanium tetrachloride used in an anhydrous state. 3. The method according to claim 1, characterized in that as iiB rtes.organisches solvent chlorobenzene, kitrobenzene or Mixtures of these two with benzene are used. 4. Process according to Claims 1 to 3, characterized in that a solution of l, l, l, 2-tetrachloro-2,2-bis (p-chlorophenyl) ethane is used in chlorobenzene and in the presence of a catalytic amount of anhydrous ferric chloride for about one hour Heated to a temperature of around 110 ° - 115 ° C. 903885/1664 BATH ORIGINAL