DD296677A5 - PROCESS FOR OBTAINING 1,1-BIS (4-CHLOROPHENYL) -2,2,2-TRICHLORETHANOL - Google Patents

Abstract

The invention relates to a process for obtaining * The process comprises the formation of an addition compound of * with a second compound acting as a maeser electron donor, the isolation of this addition compound and its subsequent decomposition. The electron-donating compound may be a hydroxylated substance, an ether, a ketone, a carboxylic acid, a sulfide and a nitrated derivative. Preferably, it is selected from dimethyl sulfoxide, cyclohexanone, isophorone, pyridine, 1,4-dioxane, acetic acid, acetonitrile and water. {Process; extraction; * Addition compound; electron donor; dimethyl sulfoxide; cyclohexanone; isophorone; pyridine; 1,4-dioxane; Acetic acid; acetonitrile; Water}

Description

For this 6 pages drawings

Field of application of the invention

The invention relates to a process for obtaining ii-bisW-chlorophenylW ^ -trichloroethanol starting from a mixture containing 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethanol (ρ, ρ'-dicofol) together with at least one compound selected from a first group consisting of 1- (4-chlorophenyl) -1- (2-chlorophenyl) -2,2,2-trichloroethanol (ο, ρ'-dicofol); 1- (4-chlorophenyl) -1- (2-chlorophenyl) -2,2,2-trichloroethane (o, p'-DDT) and 1- (4-chlorophenyl) -1- (2-chlorophenyl) -2 , 2-dichloroethylene;

In addition to the ρ, ρ'-dicofol and one or more of the compounds ο, ρ'-dicofol, ο, ρ'-DDT and ο, ρ'-DDE, the starting mixture may obviously contain other constituents. Insbesondsere may be this starting mixture 1,1-bis (chlorophenyl) -2,2,2-trichloroethanol, which is also known as technical Dicofol.

Dicofol is an acaricide used widely in agriculture, especially in cotton and orchards and for citrus fruits.

The biologically active product is 1,1-bis-H-chlorophenyl) trichloroethanol, which is present in technical dicofol in concentrations of about 70 to 7% by weight.

Characteristic of the known state of the art

The preparation of the product (dicofol) is described, inter alia, in US Pat. Nos. 2,812,280, 28,236,282 and GB-PS 3,814,221. The initially used process consisted of a photochemical chlorination (scheme A) of technical DDT, a mixture of different products whose Main components 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethane (ρ, ρ'-DDT, about 75% by weight) and 1- (4-chlorophenyl) -1- (2-chlorophenyl) -2,2,2-trichloroethane (ο, ρ'-DDT, about 20% by weight) are by melting gaseous chlorine in DDT with melting

(A)

DDT

ClDDT

resulting in the corresponding chloro derivatives 1,1-bis (4-chlorophenyl) -1,2,2,2-tetrachloroethane (ρ, ρ'-CIDDT) and 1- (4-chlorophenyl) -1- (2-chlorophenyl ) -1,2,2,2-tetrachloroethane (ο, ρ'-CIDDT).

The chlorination of the ο, ρ'-DDT isomer is incomplete due to steric hindrance, leaving a residue of this substance, corresponding to about 2 to 7% by weight, in the final chlorinated product.

The resulting from the chlorination mixture was then subjected to hydrolysis in an acidic medium (Scheme B), consisting of a heating at 120 ° C to 150 ⁰ C with an aqueous sulfuric acid solution and an arylsulfonic acid.

(B)

ClDDT

DICOFOL

The dicofol was extracted by dissolving in a solvent and quenching, washing the organic phase with water and recovering the dicofol by distilling off the solvent.

The o, p'-DDT was unaffected by this hydrolysis, and therefore the final content thereof in the technical dicofol was about 2 to 6%.

With a view to reducing this content, the process of preparation was modified by altering the chlorination by first preparing the DDT by dehydrochlorination with a strong base (Scheme C) into the corresponding ethylene derivatives 1,1-bis (4-chlorophenyl) -2, 2, -dichloroethylene (p, p'DDE) and 1- (4-chlorophenyl) -1- (2-chlorophenyl) -2,2-dichloroethylene (ο, ρ'-DDE)

^C1 - (O

DDT

DDE

and subsequent photochemical addition of chlorine (Scheme D) to give the same chlorinated derivative as in the previous case, which was subjected to the same acid hydrolysis procedure.

CCI.

ClDDT

Nevertheless, dicofol made by one of these processes contains a number of impurities, some of which are related to DDT and called DDT.R, of which the following are known:

/ v

ρ, ρ'-DDT

Ο, ρ'-DDT

Cl

Cl

ρ, ρ'-DDD

ο, p'-DDD

p, p'-DDE

Ο, ρ'DDE

ρ, ρ'-ClDDT

O, ρ'-ClDDT

CCl ₃

Other known impurities contained in oicofol and not referred to as DDT.R are 4,4'-dichlorobenzophenone (ρ, ρ'-DCBF), 2,4-dichlorobenzophenone (ο, ρ'-DCBF), 4, 4'-dichlorobenzyl (ρ, ρ'-DCBZ) and 2,4'-dichlorobenzyl (o, p'-DCBZ).

C-COV ^C1 P, P "-DCBF

ο, ρ'-DCBF

ρ, ρ'-DCBZ o, p "-DCBZ

The presence of these impurities, especially those related to DDT and generally known as DDT.R., leads to ecological disadvantages, the content of these impurities being subject to limitations and being allowed to amount to a maximum of 0.1% by weight a cleaning of the product is required.

US Patent 4,705,592 and ES Patents 8603248 and 8802818 describe technical dicofol cleaning processes

Liquid-liquid extraction, whereby it is possible to reduce the DDT.R content below 0.1 wt .-%.

Nevertheless, the content of the effective ingredient (1,1-bis (4-chlorophenyl) -2,2,2-trichloroethanol (ρ, ρ'-dicofol) is still small and is between 75 and 80%, which is an unnecessary burden the environment with additional products when applying the dicofol means.

Object of the invention

The aim of the invention is the development of a process for obtaining a product with a high content of 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethanol (p, p'Dicofol), which are even more than 98% can, and a low content of DDT.R impurities, which may even be less than 0.1 wt .-%.

Explanation of the essence of the invention

The process according to the invention is characterized by the formation of an addition compound of 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethanol with a second compound acting as a moderate electron donor, such as a hydroxylated substance, an ether, a ketone, a carboxylic acid, a sulfoxide and a nitrated derivative, isolation of these

Addition compound and subsequent decomposition of said addition compound.

The second compound mentioned is preferably selected according to the invention from dimethyl sulfoxide, cyclohexanone,

Isophorone, pyridine, 1,4-dioxane, acetic acid, acetonitrile and water.

The method according to the invention is based - as stated above - on the fact that 1.1-bis (4-

chlorophenyl) -2,2,2-trichloroethanol (ρ, ρ'-dicofol) in view of the specific electrophilic nature of hydroxyl hydrogen

Addition compounds with different substances such as water, alcohols, ethers, ketones, carboxylic acids, sulfoxides, sulfones, nitrated derivatives, etc. forms.

Some of these addition compounds are readily isolable crystalline solids according to the composition and properties given in Table 1.

Table 1

Addition compounds of i.i-bisM-chlorophenyl ^^^ trichloroethanol

dimethyl sulfoxide

(P-CIC ₆ H ₄ J ₂ C (OH) CCl ₃ · (CH ₂ J ₂ SO m.p. 93.0 to 93.5 C ⁰

2 (P-CIC ₆ H ₄ I ₂ C (OH) CCl ₃ - (CH ₂ S) ₂ SO ₃ Fp 103.8-104.7

cyclohexanone

(P-CIC ₆ H ₄ I ₂ C (OH) CCI ₃ .C ₆ H ₁₀ O Fp 56.0-57.0

isophorone

(p-CIC ₆ H ₄ ) ₂ C (OH) CCI ₃ .C ₉ H ₁₄ O Fp 68.6-69.5

pyridine

(P-CIC ₆ H ₄ I ₂ C (OH) CCl ₃ C ₅ H ₅ N Fp 81.8-82.9

1,4-dioxane

2 (P-CIC ₆ H ₄ I ₂ C (OH) CCl ₃ -C ₄ H ₈ O ₂ Fp 70.6-71.8

acetic acid

(P-CIC ₆ Hi) ₂ C (OH) CCI ₃ .C ₂ H ₄ O ₂ Fp 57.4-58.2

acetonitrile

(P-CIC ₆ H ₄ ) ZC (OH) CCI ₃ .C ₂ H ₃ N Fp unknown

water

(P-CIC ₆ H ₄ J ₂ C (OH) CCl ₃ x H ₂ O Fp unknown

These addition compounds can be separated into their components, either by heat treatment under normal or reduced pressure or by washing with water or other hydroxyl-containing derivatives.

The selectivity of the formation of these addition compounds, their insolubility in certain solvents, and the ability to decompose them, enables a process by which it is possible to prepare 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethanol (p, p '· Dicofol), from mixtures in which it is contained, to obtain in yields of over 90%.

The starting mixtures containing ii-bisM-chlorophenyi-trichloroethanol (ρ, ρ'-dicofol) are preferably those in which the (ρ, ρ'-dicofol) is accompanied mainly by 1- (4-chlorophenyl) - 1- (2-chlorophenyl) -2,2,2-trichloroethanol (o, p'-dicofol), ie technical dicofol; 1- (4-chlorophenyl) -1- (2-chlorophenyl) -2,2-dichloroethylene (ο, ρ'-DDE); and / or 1- (4-chlorophenyl) -1- (2-chlorophenyl) -2,2,2-trichloroethane (o, p'-DDT).

When the starting mixture is technical dicofol, amounts of 1- (4-chlorophenyl) -1- (2-chlorophenyl) -2,2,2-trichloroethanol (ο, ρ'-dicofol), as such, ranging from 0.1 and 12% by weight in the final product, together with the addition compound 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethanol (ρ, ρ'-dicofol).

Whether the amount of ο, ρ'-diocofol separated is larger or smaller depends on the kind and amount of the solvent used, the temperature conditions and the crystallization time, and the amount of any seed crystals present.

According to the invention, the process comprises stages of: a) forming a solution of the mixture containing 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethanol, (ρ, ρ'-dicofol) in a solvent; b) addition of the reactant to form the addition compound; c) cooling the solution and crystallizing addition compound, optionally with the addition of seed crystals; d) filtering and washing the addition compound; and e) recovering 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethanol.

Optionally, and in addition to the above steps, the separation of 4,4'-dichlorobenzyl (ρ, ρ'-DCBZ) can be interposed by crystallization and filtration between the above steps.

Preferably, the solvent used in step a) is an aromatic compound such as xylene or monochlorobenzene, a halogenated compound such as carbon tetrachloride, an aliphatic compound such as hexane or decane or mixtures thereof or a sulfur-containing compound.

As an alternative feature of the invention, this sulfur-containing compound is aqueous dimethyl sulfoxide, and stages a) and

b) are carried out simultaneously.

In a preferred embodiment, the same solvent used in step a) is used for washing.

The reactants used in step b) to form the addition compound are preferably water, ethanol, such as dioxane, ketones, such as cyclohexanone and isophorone, carboxylic acids, such as acetic acid, sulfoxides, such as dimethyl sulfoxide, or nitrated derivatives, such as pyridine and acetonitrile.

Optionally, the step e), namely the recovery, is carried out by heating the addition compound to a temperature in the range of 20 ⁰ C to 140 ⁰ C at reduced pressure of 1 to 300mbar or by treating the addition compound with water at a temperature in the range of 80 ° C 100 ⁰ C or by dissolving this addition compound in water-immiscible organic compounds and subsequent washing with water.

The 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethanol which can be prepared by the process of the present invention can be used as the acaricide.

The invention also relates to a process for the preparation of the addition compounds of 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethanol. These addition compounds themselves can also be used as acaricide as well as an intermediate for the preparation of 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethanol.

Brief Description of the Drawings Figures 1 to 3 are chromatograms formed by high performance liquid chromatography (HPLC), in which the residence times in minutes are indicated on the abscissa and the intensities of UV absorption on the ordinate. It is in particular

Fig. 2: an HPLC chromatogram of dicofol, which has been purified by liquid-liquid extraction, wherein the

Composition in the second column of Table 2 is given. Fig. 3: an HPLC chromatogram of dicofol, which has been purified by the method according to the invention and its

Composition in the third column of Table 2 is given. Fig. 4: is an IR spectrum of the addition compound formed from 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethanol and dimethyl sulfoxide, with the wavelengths in cm "'on the abscissa and the Permeability in% on the ordinate

is specified. Fig. 5: is a proton NMR spectrum of the mentioned addition compound. On the abscissa, the chemical shifts, based on tetramethylsilane, in ppm and the radiation absorption intensity is on the

Ordinate indicated. Fig. 6: is a thermogravimetric analysis of the addition compound. The relative weight of the sample (2 mg equals 100 on the scale) is given on the ordinate. The change over time, when the product is isothermally held at 120 ⁰ C, is indicated on the abscissa (5mm / min).

The qualitative and quantitative determination of the impurities contained in the dicofol, as stated above, can be carried out by HPLC analysis. FIG. 1 is a chromatogram of the technical dicofol used as the starting substance, wherein the reference numbers given in the individual peaks have the following meaning.

reference number

9 10 11 12 13 14

product

ο, ρ'-DCBF

o, p-DCBZ

p, p'-DCBF

p, p'-DCBZ

o p'dicofol

p, p'-DDD

o, p'-DDD

p, p'-dicofol

o, p-DDE

p, p'-DDT

o, p'-DDT

p, p'-DDE

o, p-CIDDT

p, p'-CIDDT

The composition derived for this technical dicofol is shown in the first column of Table 2.

Table 2

Comparison of the composition of technical Dicofol with that of Dicofl, which has been purified by liquid-liquid extraction or by the inventive method

Starting material technical Dicofol

p, p'-dicofol o, p'-dicofol p, p'-DCBF o, ρ'-DCBF p, p'-DCBZ o, p'-DCBZ p, p'-DDD o, p'-DDD p, p'-DDE o, p'-DDE ρ, ρ'-DDT o, p'-DDT p, p'-CIDDT o, p'-CIDDT not identified

dicofol purified dicofol fiction, Liquid-liquid according to extraction 99.1% by weight 70,5Gew .-% 78,5Gew .-% 0.6 14.7 16.9 <5ppm 0.4 0.25 <5 0.4 0.38 0.2% by weight 0.7 0.30 50 ppm 1.3 1.39 <5ppm 0.01 16ppm <5 0.01 5 <5 0.03 12 <5 0.10 45 <5 0.01 5 <5 0.01 5 200 3.5 30 8th 0.6 10 0.1% by weight 7.8 2% by weight

embodiments

The invention is further illustrated by the following examples.

example 1

50.0 g of technical grade dicofol, having a ρ, ρ'-dicofol content of 70.5% (column 1, Table 2), were dissolved in a mixture of 26.9 g of xylene and 30.0 g of hexane. Then 9.0 g of dimethyl sulfoxide were added and the solution heated to 60 ⁰ C for 1 h. The mixture was allowed to crystallize to -1O ⁰ C with stirring and cooling. It was filtered and washed with the xylene / hexane mixture. There were obtained 40.1 g of the addition compound (pure melting point 93.0 to 93.5 ⁰ C).

Elemental analysis (% by weight) for C ₁₆ H ₁₅ O ₂ Cl ₅ S:

calc .: C = 42.83; H = 3.37; S = 7.15; Cl = 39.55; Found .: C = 42.89; H = 3.21; S = 7.14; Cl = 39.67; and C = 43.03; H = 3.20; S = 6.91; Cl = 39.81.

The IR spectrum (Rg.4) and the proton NMR spectrum (Fig. 6) are in agreement with the addition compound. The addition compound was dissolved in 40OgXyIoI at room temperature and, also at room temperature, treated twice with 40g of water. The xylene was distilled off. This gave 32.8 g of dicofol with a content of ρ, ρ'-dicofol of 97.8% and a yield of 94.4% and the following composition (in% by weight): p, p'-DCBZ, 1, 0; ο, ρ'-dicofol, 1,1; ρ, ρ'-dicofol, 97.8; p, p'-CIDDT, 0.05; other DDT (R), <0.1.

Example 2

50.0 g of technical dicofol, with a ρ, ρ'-dicofol content of 70.5% (column 1, Table 2), were dissolved in 50 g of carbon tetrachloride. Then, 9.0 g of dimethyl sulfoxide was added and the solution was crystallized while stirring and cooling to ⁰ ° C. The mixture was filtered and washed with carbon tetrachloride. 31.8 g of the addition compound were obtained.

This was heated under reduced pressure of 2.66 mbar (5 mm Hg) under a gentle current of air at 120 ⁰ C and held for 5 hours under these conditions.

This gave 24.8 g of dicofol with a content of 98.1% ρ, ρ'-dicofol in a yield of 68.9% and the following composition (% by weight): p, p'-DCBZ, 1.0; ο, ρ'-dicofol, 0.6; ρ, ρ'-dicofol, 98.1; DDT (R), <0.1.

Example 3

50.0 g of technical grade dicofol, containing 70.5% of ρ, ρ'-dicofol (column 1, Table 2), was dissolved in 26.9 g of xylene and 9.0 g of dimethylsulfoxide was added to the solution and heated to 60 h for 1 h ° C heated. The mixture was caused to crystallize with stirring and cooling to -10 ⁰ C. It was filtered and seen with xylene gewä. This gave 35.7 g of the addition compound, which was dissolved in 35 g of n-decane at 95 ° C and treated twice with 35 g of water of 95 ⁰ C. The n-decane was distilled off. This gave 29.9 g of dicofol with 98.1% ρ, ρ'-dicofol content in a yield of 80.3% with a composition (wt .-%): p, p'-DCBZ, 1.1; o, p'-dicofol, 0.6; ρ, ρ'-dicofol, 98.1; DDT (R), <0.1.

Example 4

50.0% technical dicofol, having a content of ρ, ρ'-dicofol of 70.5% (column 1, table 2), was dissolved in 59.0 g of a mixture of 52.7 g of dimethyl sulfoxide and 6.3 g of water. The solution was heated to 6O ⁰ C for 1 h and crystallized with stirring and cooling to 0 ⁰ C. The mixture was filtered and washed with dimethyl sulfoxide / water. This gave 46.9 g of the addition compound, which was heated to 95 ° C and treated twice with 90 g of water of 95 ⁰ C. This gave 32.8 g of dicofol with 93.4% ρ, ρ'-dicofol, corresponding to a yield of 87.0% and the following composition (wt .-%): o, p'-DCBF, 0.1; o, p'-DCBZ, 0.3; p, p'-DCBF, 0.1; ρ, ρ'-DCBZ, 0.9; ο, ρ'-dicofol, 4,7; ρ, ρ'-dicofol, 93.4; p, p'-CIDDT, 0.06; other DDT (R], <0.1.

Example 5

50.0 g of technical dicofol, with a ρ, ρ'-dicofol content of 70.5% (column 1, Table 2), were dissolved in a mixture of 25.0 g of monochlorobenzene and 30 g of hexane. The solution was cooled to ⁰ ° C. and the precipitated ρ, ρ'-DCBZ was filtered off. The solution was heated at 3O ⁰ C and 9 g of dimethyl sulfoxide was added. It was heated for 1 h to 6O ⁰ C and brought to crystallization with stirring and cooling to -10 ⁰ C. The mixture was filtered and washed in the filter with the monochlorobenzene / hexane mixture. This gave 38.4 g of the addition compound, which was heated to 95 ° C and treated twice with 80 g of water at 95 ° C.

This gave 31.6 g of dicofol with a content of 99.1% ρ, ρ'-dicofol, corresponding to a yield of 89% and a composition (wt .-%): ρ, ρ'-DCBZ, 0.2; ο, ρ'-dicofol, 0.6; ρ, ρ'-dicofol, 99.1; DDT (R), <0.1.

Example 6

50.0 g technical dicofol, with a ρ, ρ'-dicofol content of 70.5% (column 1, Table 2) were dissolved in 46.0 g of hexane and 12.5 g of cyclohexanone were added. The mixture was crystallized by stirring and cooling to 5 ° C, then filtered and washed with 18.0 g of hexane. This gave 36.7 g of the addition product (pure melting point 56.0 to 57, O ⁰ C). Elemental analysis (wt%) for C ₂ OH ₁₃ O ₂ Cl ₆ :

Calc .: C = 51.25; H = 4.09; Cl = 37.82; found: C = 51.29; H = 4.00; Cl = 38.08; and C-51.48; H = 3.98; Cl = 38.13.

The IR and proton NMR spectrum were consistent with the addition compound. This was heated under reduced pressure of 2,66mbar (2 mm) Hg with a gentle stream of air at 120 ⁰ C.

This gave 28.8 g of dicofol with a ρ, ρ'-dicofol content of 96.0% in a yield of 78.4% and with a composition (wt .-%): ρ, ρ'-DCBZ, 2.1 ; ο, ρ'-dicofol, 1,2; ρ, ρ'-dicofol, 96.0; p, p'-CIDDT, 0.2; other DDT (R), <0.1.

Example 7

50, Og technical dicofol, with a ρ, ρ'-dicofol content of 70.5% (column 1, Table 2) were dissolved in 45.9 g of hexane and 9.1 g of pyridine added. The mixture was crystallized with stirring and cooling to 20 ⁰ C, filtered and washed with 20 g of hexane. This gave 37.9 g of the addition compound (pure melting point 81.8 to 82.9 ⁰ C).

Elemental analysis (wt%) for Ci ₉ H ₁₄ ONCI ₅ :

Calc .: C = 50.75; H = 3.14; N = 3.12; Cl = 39.42; Found: C = 50.72; H = 3.04; N = 3.07; Cl = 39.63; and C = 50.69; H = 3.09; N = 3.05; Cl = 39.56.

The IR and proton NMR spectrum were consistent with the addition compound. This was dissolved in 37.9 g of monochlorobenzene and washed several times with 30.0 g of acidified water until the pyridine was removed.

The monochlorobenzene was distilled off to obtain 31.9 g of dicofol having 96.9% ρ, ρ'-dicofol content in a yield of 87.6% having the following composition (% by weight): p, p'-DCBF , 0.1; p, p'-DCBZ, 1.8; o, p'-dicofol, 0.8; p, p'-dicofol, 96.9; p, p'-DIDDT, 0.2; other DDT (R), <0.1.

Example 8

50.0 g of technical grade dicofol having a ρ, ρ'-dicofol content of 70.5% (column 1, Table 2) was dissolved in 49.7 g of hexane and 15.9 g of isophorone was added. The mixture was crystallized by stirring and cooling to 5 ° C. It was washed with 20.0 g of hexane. This gave 41.1 g of the addition compound (pure melting point 68.6 to 69.5 ° C). Elemental analysis (% by weight) for C ₂₃ H ₂₃ O ₂ Cl ₅ :

calc .: C = 54.30; H = 4.57; Cl = 34.84; Found .: C = 54.34; H = 4.54; Cl = 34.80; and C = 54.43; H = 4.56; Cl = 35.07.

The IR and proton NMR spectrum were consistent with the addition compound. This was heated to 120 ° C under reduced pressure of 2.66 mbar (2 mm) Hg under a gentle stream of air.

This gave 30.8 g of dicofol with 93.5% ρ, ρ'-dicofol content in a yield of 81.5% and a composition (wt .-%): o, p'-DCBF, 0.1; p, p'-DCBZ, 1.9; o, p'-dicofol, 3.8; p, p'-dicofol, 93.5; p, p'-CIDDT, 0.1; other DDT (R), <0.1.

Example 9

50.0 g of technical grade dicofol, with a ρ, ρ'-dicofol content of 70.5% (column 1, Table 2), were dissolved in 49.0 g of hexane. 7.2 g of glacial acetic acid were added. The mixture was crystallized with stirring and cooling to 7 ° C, filtered and washed with 11.3 g of hexane. This gave 29.7 g of the addition compound (pure melting point 57.4 to 58.2 ⁰ C). Elemental analysis (% by weight) for C ₁₆ Hi ₃ O ₃ Cl ₅ :

calc .: C = 44.63; H = 3.05; Cl = 41.17; Found .: C = 44.57; H = 3.06; Cl = 41.64; and C = 44.65; H = 2.91; Cl = 41.73.

The IR and proton NMR spectrum were consistent with the addition compound. This was dissolved in 29.5 g of monochlorobenzene and washed with 30 g of water until the acetic acid was removed.

The monochlorobenzene was distilled off to give 26.6 g of dicofol with 95.9% ρ, ρ'-dicofol content in a yield of 72.2% with a composition (% by weight): p, p'-DCBZ, 2.2; o, p'-dicofol, 1.7; p, p'-dicofol, 95.9; p, p'-CIDDT, 0.1; other DDT (R), <0.1.

Example 10

50.0 g of technical grade dicofol, having a ρ, ρ'-dicofol content of 70.5% (column 1, Table 2), was dissolved in 47.0 g of hexane and 10.1 g of 1,4-dioxane was added. The mixture was crystallized with stirring and cooling to 20 ⁰ C, filtered and washed with 9.4 g of hexane. This gave 13.0 g of the addition product (pure melting point 70.6 to 71.8 ° C). Elemental analysis (wt%) for C ₃₂ H ₂ BO ₄ Cl ₁ Q:

calc .: C = 46.35; H = 3.17; Cl = 42.76; Found .: C = 46.39; H = 3.11; Cl = 42.70; and C = 46.23; H = 3.10; Cl = 42.64.

The IR and proton NMR spectrum were consistent with the addition compound. This was dissolved in 12.9 g of monochlorobenzene and washed several times with 10 g of water.

The monochlorobenzene was distilled off. This gave 12 g of dicofol with 94.5% ρ, ρ'-dicofol content in a yield of 31.9% with the composition (wt .-%): p, p'-DCBZ, 4.0; o, p'-dicofol, 1.1; p, p'-dicofol, 94.5; p, p'-CIDDT, 0.3.

Example 11

50.0 g of technical grade dicofol, having a ρ, ρ'-dicofol content of 70.5% (column 1, Table 2), was dissolved in 49.0 g of hexane and 4.7 g of acetonitrile were added. The mixture was crystallized by stirring and cooling to 20 ^° C. It was filtered and dissolved with 20 g of hexane. This gave 26.5 g of the addition compound (mp: unstable at room temperature), which was dissolved in 25 g of monochlorobenzene and washed twice with 15 g of water.

The monochlorobenzene was distilled off. This gave 23.7 g of dicofol with 90.8% ρ, ρ'-dicofol content in a yield of 61.0% with the composition (wt .-%): o, p'-DCBF, 0.1; o, p'-DCBZ, 0.6; p, p'-DCBF, 0.2; p, p'-DCBZ, 2.0; o, p'-dicofol, 5.2; p, p'-dicofol, 90.8; p, p'-CIDDT, 0.2; other DDT (R), <0.1.

Example 12

50.0g of a mixture of the following composition in wt%: o, p'-DCBF, 0.1; o, p'-DCBZ, 0.2; p, p'-DCBF, 0.3; p, p'-DCBZ, 1.0; o, p'-dicofol, 0.5; p, p'-dicofol, 76.0; o, p'-DDE, 15.2; ρ, ρ'-DDE, <0.1; ο, ρ'-CIDDT, 0,1; ρ, ρ'-CIDDT, 3.1; Residue 3.4, was dissolved in a mixture of 31.8 g monochlorobenzene and 31.8 g n-decane. It was cooled to 0 ⁰ C, and the precipitating p, p'-DCBZ filtered off. It was then warmed to 30 ⁰ C and 11.3 g of water was added. It was cooled to 5 ° C with vigorous stirring, filtered and washed with 11.0 g of hexane.

24.0 g of the addition product (it was not possible to adequately purify this product for exact identification) was obtained having a ρ, ρ'-dicofol content of 86.4% and 11.5% water.

The addition product melted at 80 ⁰ C, the supernatant water was decanted and the product at 80 ⁰ C and 6.66 mbar (5 mm Hg). This gave 21.6 g of dicofol with 98.8% ρ, ρ'-dicofol content in a yield of 55.9% and a composition (wt .-%): p, p'-DCBZ, 0.3; p, p'-dicofol, 98.8; o, p'-DDE, 0.1; ρ, ρ'-CIDDT, 0.8.

Example 13

50 mg of the same mixture as in the previous example were dissolved in 31.8 g of monochlorobenzene and 31.8 g of n-decane. It was cooled to 0 ° C and the separating ρ, ρ'-DCBZ removed. It was heated to 30 ° C and 4.1 g of dimethyl sulfoxide (0.52 mol dimethyl sulfoxide / mole ρ, ρ'-dicofol) was added. The mixture was caused to crystallize with stirring and cooling to -10 ⁰ C. It was filtered and washed with 8.5 g of a mixture of monochlorobenzene and n-decane. This gave 39.6 g of the addition compound (pure melting point 103.8 to 104.7 ⁰ C).

Elemental analysis (% by weight) for C ₃₀ H ₂₄ O ₃ Cl ₁₀ S:

calc .: C = 43.99; H = 2.96; S = 3.91; Cl = 43.28; Found .: C = 44.12; H = 2.94; S = 3.91; Cl = 43.66; and C = 44.09; H = 2.93; S = 3.74; Cl = 43.53.

The IR and proton NMR spectrum were consistent with the addition compound. This was dissolved in 17 g of monochlorobenzene and washed three times with 17 g of water.

The monochlorobenzene was distilled off. This gave 34.2 g of dicofol with 99.2% ρ, ρ'-dicofol content in a yield of 91.3% with the composition (wt .-%): ρ, ρ'-DCBZ, 0.5; ρ, ρ'-dicofol, 99.2; o, p'-DDE, 0.03; ρ, ρ'-CIDDT, 0.15.

Example 14

50.0 g of a mixture of the following composition in% by weight: ο, ρ'-DCBF, <0.1; o, p'-DCBZ, 0.2; ρ, ρ'-DCBF, 0.6; ρ, ρ'-DCBZ, 1.3; o, p'-dicofol, ρ, ρ'-dicofol, 74.0; o, p'-DDE, 17.6; ρ, ρ'-DDE, 0.2; ο, ρ'-CIDDT, 0,1; ρ, ρ'-CIDDT, 3.0; Residue 2.6, was dissolved in a mixture of 23.8 g of monochlorobenzene and 35.9 g of n-decane, cooled to ⁰ ° C. and the precipitated DCBZ filtered off.

The mixture was heated to 4O ⁰ C and 8.1 g of dimethylsulfoxide was added. The mixture was crystallized with stirring and cooling to -10 ° C, filtered and washed with 20.8 g of the same mixture of monochlorobenzene and n-decane.

This gave 44.0 g of the addition product, which was dissolved in 18.5 g monochlorobenzene of 70 ° C and washed three times with 18.5 g of water.

The monochlorobenzene was distilled off. This gave 34.7 g of dicofol with 99.5% ρ, ρ'-dicofol content in a yield of 93.3% with the composition (wt .-%): ρ, ρ'-DCBZ, 0.3; ρ, ρ'-dicofol, 99.5; DDT (R), <0.1.

Example 15

50.0 g of a mixture of the following composition (% by weight): ο, ρ'-DCBF, 0.1; o, p'-DCBZ, 0.3, ρ, ρ'-DCBF, 0.6; ρ, ρ'-DCBZ, 1.2; o, p'-dicofol, 2.2; ρ, ρ'-dicofol, 73.2; o, p'-DDE, 6.2; o, p'-DDT, 8.6; ρ, ρ'-DDE, 0.1; ο, ρ'-CIDDT, 0.2; ρ, ρ'-CIDDT, 2.9; The residue, 4.4, was dissolved in a mixture of 29.5 g of monochlorobenzene and 29.5 g of n-decane, cooled to ⁰ ° C., and the precipitating ρ, ρ'-DCBZ was filtered off. The mixture was heated at 3O ⁰ C and 8.4 g of dimethylsulfoxide was added. The mixture was brought under stirring and cooling to -10 ⁰ C for crystallization, filtered and washed with 15 g of the same mixture of monochlorobenzene and n-decane. This gave 44.2 g of the addition product, which was dissolved in 20 g monochlorobenzene at 70 ° C and washed three times with 20 g of water.

The monochlorobenzene was distilled off. This gave 34.1 g of dicofol with 99.0% ρ, ρ'-dicofol content in a yield of 92.1 ° Ό with the composition (wt .-%): ρ, ρ'-DCBZ, 0.5; ρ, ρ'-dicofol, 99.0; DDT (R), <0.1.

Example 16

50.0 g of technical dicofol (column 1, Table 2) were dissolved in a mixture of 29.5 g of monochlorobenzene and 29.5 n-decane. The solution was cooled to ⁰ ° C. and the precipitating ρ, ρ'-DCBZ was filtered off. The solution was heated to 30 ⁰ C and 9.0 g of dimethyl sulfoxide was added. After seeding with ο, ρ'-dicofol, it was induced to crystallize with stirring and cooling to -10 ⁰ C during a prolonged period of time. The mixture was filtered and washed with the same monochlorobenzene / n-decane mixture. This gave 45 g of the addition product, which was dissolved in 20 g monochlorobenzene of 70 ⁰ C and washed three times with 20 g of water. The monochlorobenzene was distilled off. 67.5 g of dicofol of the following composition (% by weight) were obtained: ρ, ρ'-DCBZ, 0.6; ο, ρ'-dicofol, 9.3; ρ, ρ'-dicofol, 89.6; DDT (R), <0.1.

Example 17

60.0 g of a mixture of the following composition (% by weight): ο, ρ'-DCBF, 0.1; o, p'-DCBZ, 0.2; ρ, ρ'-DCBF, 0.6; ρ, ρ'-DCBZ, 1.4; ο, ρ'-dicofol, 1,1; ρ, ρ'-dicofol, 73.9; o, p'-DDE, 17.6; ρ, ρ'-DDE, 0.2; ο, ρ'-CIDDT, 0.1; ρ, ρ'-CIDDT, 3.0; Remainder, 1.8, were dissolved in 60.0 g of n-decane of 60 ⁰ C. It 2.0 g of the finest silica were added and then filtered at 6O ⁰ C. Then, 8.3 g of dimethylsulfoxide was slowly added to 105.0 g of the filtered solution containing 37.0 g of ρ, ρ'-dicofol at 60 ° C. The

Addition compound began to crystallize when 60% dimethylsulfoxide was added. It was cooled to 15 ° C, filtered and washed with 20.0 g of n-decane. 47.3 g of the addition product were obtained. This was dissolved in 20.0 g of monochlorobenzene and washed three times with 20.0 g of water.

The monochlorobenzene was distilled off and 36.3 g of dicofol with 98.0% ρ, ρ'-dicofol-Q content in a yield of 97.5% obtained with the composition (wt .-%): p, p'-DCBZ, 1, 9; p, p'-dicofol, 98.0; DDT (R), <0.1.

By dissolving in an equal amount by weight of isopropyl alcohol in the heat, cooling to 20 ^° C., filtering and removing the isopropyl alcohol, dicofol having the following composition (% by weight) was obtained: p, p'-DCBZ, 0.2; p, p'-dicofol, 99.7; DDT (R), <0.1.

Claims (20)

A process for obtaining ii-bis (chlorophenyl) trichloroethanol starting from a mixture containing 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethanol together with at least one compound selected from a first group consisting of 1- (4-chlorophenyl) -1- (2-chlorophenyl) -2,2,2-trichloroethanol, 1- (4-chlorophenyl) -1- (2-chlorophenyl) -2,2,2 trichloroethane and 1- (4-chlorophenyl) -1- (2-chlorophenyl) -2,2-dichloroethylene, characterized by the formation of an addition compound of 1,1-bis (4-chlorophenyl) -2,2,2 trichloroethanol and a second compound acting as a moderate electron donor, such as a hydroxyl-containing substance, an ether, a ketone, a carboxylic acid, a sulfoxide or a nitrated derivative, isolation of the addition compound and subsequent decomposition of this addition compound. 2. The method according to claim 1, characterized in that the second compound is selected from dimethyl sulfoxide, cyclohexanone, isophorone, pyridine, 1,4-dioxane, acetic acid, acetonitrile and water. 3. The method according to claim 1 and 2, characterized in that it comprises the following stages: a) formation of a solution of the starting mixture in a solvent; b) adding the second compound to the solution to form a mass in which the addition compound is formed; c) cooling this mass and crystallizing the addition compound; d) filtering and washing the addition compound and e) Recovery of 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethanol. 4. The method according to claim 1, characterized in that the starting mixture technical 1,1-bis (chlorophenyl) -2,2,2-trichloroethanol (also known as technical Dicofol) is. 5. The method according to claim 3 and 4, characterized in that in step c) 1- (4-chlorophenyl) -1- (2-chlorophenyl) -2,2,2-trichloroethanol is crystallized together with the crystallization of the addition compound. 6. The method according to claim 5, characterized in that seed crystals of 1- (4-chlorophenyl) -1- (2-chlorophenyl) -2,2,2-trichloroethanol are added to the mass to the crystallization of the latter compound accelerate. 7. The method according to claim 3, characterized in that in step a) the solvent is an aromatic compound, a halogenated compound, an aliphatic compound or a mixture thereof or a sulfur-containing compound. 8. The method according to claim 7, characterized in that the aromatic compound is xylene or monochlorobenzene. 9. The method according to claim 7, characterized in that the halogenated compound is carbon tetrachloride. 10. The method according to claim 7, characterized in that the aliphatic compound is hexane or n-decane. 11. The method according to claim 7, characterized in that the sulfur compound is aqueous dimethyl sulfoxide and the steps a) and b) are carried out simultaneously. 12. The method according to claims 3 to 11, characterized in that the steps a) and b) at temperatures in the range of 0 ⁰ C to 100 ⁰ C and the steps c) and d) at temperatures in the range of -20 ⁰ C. be carried out to 40 ⁰ C. 13. The method according to claim 12, characterized in that the steps a) and b) are carried out at temperatures in the range of 10 ° C to 20 ^c C. 14. The method according to claims 3 to 13, characterized in that the washing is carried out with the same solvent used in step a). 15. Process according to claims 3 to 14, characterized in that the recovery is carried out by heating the addition compound to a temperature in the range of 20 ⁰ C to 140X under a reduced pressure of 1 to 300mbr. 16. The method according to claims 3 to 14, characterized in that the recovery is carried out by treatment of the addition compound with water at a temperature in the range of 80 ° C to 100 ⁰ C. 17. Process according to claims 3 to 14, characterized in that the recovery is carried out by dissolving the addition compound in water-immiscible organic solvents and subsequent washing with water. 18. The method according to claim 17, characterized in that the organic solvent is distilled off. 19. A process for the preparation of addition compounds from 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethanol, starting from a mixture containing 1,1-bis (4-chlorophenyl) -2,2,2- trichloroethanol together with at least one compound selected from a first group consisting of 1- (4-chlorophenyl) -1- (2-chlorophenyl) -2,2,2-trichloroethanol _/ 1- (4-chlorophenyl) -1- ( 2-chlorophenyl) -2,2,2-trichloroethane and 1- (4-chlorophenyl) -1- (2-chlorophenyl) -2,2-dichloroethylene, characterized in that it comprises the following steps: a) formation of a solution of the starting mixture in a solvent and b) adding a moderate electron donating compound such as a hydroxyl-containing substance, an ether, a ketone, a carboxylic acid, a sulfoxide and a nitrated derivative to the solution to obtain a composition in which the addition compound is formed and c) cooling this mass and crystallizing the addition compound and d) filtering and washing the addition compound. 20. The method according to claim 19, characterized in that the second compound is selected from dimethyl sulfoxide, cyclohexanone, isophorone, pyridine, 1,4-dioxane, acetic acid, acetonitrile and water.