The method of separation of 1,4-dichlorobutene-2

 

(57) Abstract:

The invention relates to a method for allocation of 1,4-dichlorobutene-2 from a mixture WITH4-chlorohydrocarbons, obtained by liquid-phase chlorination of butadiene. Mix WITH4-chlorohydrocarbons, containing mainly dichlorobutene and trichlorobutene, is subjected to selective water-alkaline dehydrochlorination 30-46 wt. % aqueous Paon at a temperature of 13-20C in the environment of ethyl chloride with the use of a catalytic system consisting of trialkyl-1-harbutt-2-yl ammonium chloride and alcohol components, which includes alcohol1-C4or benzyl alcohol, or 1,4-butandiol. The catalytic system is obtained directly in a mixture dehydrochlorinated4-chlorohydrocarbons. The improved method allows you to select 1,4-dichlorobutene-2 without prior distillation of the mixture WITH4-chlorohydrocarbons. 2 C.p. f-crystals.

The invention relates to organic synthesis, in particular 1,4-dichlorobutene-2 from a mixture of C4-chlorophenolate obtained by liquid-phase chlorination of butadiene. 1,4-dichlorobutene-2 is a valuable intermediate in organic synthesis, and is also used to obtain 3,4-dichlorobutene-1, predescu the on-1,3(1) with chlorine in a solvent (CCl4, CHCl3, di-, tri - and tetrachlorethane, C4H8Cl2C6H6, PhCl, PhNO2C6H11C7H16, cyclohexane and so on) in the presence of 0.1-5% (by weight of the solvent) sulphur or substances containing sulphur (CS2, Na2S, CaS, Na2S2O3H2, thiophene, mercaptans) at a temperature of from -20 to 50oC, is obtained without high-boiling impurities dichlorobutene. Yield > 90% (1 mol of chlorine per 1 mol (1) or tetrachlorobutane, yield > 90% (1 mol of chlorine per 1 mol (1) or tetrachlorobutane, yield > 95% (2 mol of chlorine per 1 mol (1)). (Japan patent 19564, op.1967, RICH NP, 1968).

The disadvantage of this method is:

the use of high-boiling solvents, the allocation of which at elevated temperatures leads to the formation of resinous products, polluting the distillation trichlorobutene and tetrachlorobutane that can be used to obtain valuable dichlorobutadiene;

the complexity of catalytic systems.

Also known is a method of obtaining dichlorobutenes, namely, that the chlorination of butadiene is carried out in an environment of carbon tetrachloride at -5 - 0oC in the presence as catalyst of dimethylformamide, dimethylacetamide or pyridine, taken in the quantity of temperature, which is difficult to observe, also, the use of high-boiling solvent.

Closest to the claimed technical essence and the achieved effect is a method of obtaining dichlorobutene by the chlorination of butadiene chlorine in the presence of a catalyst of dimethylformamide in an environment of carbon tetrachloride, followed by distillation of the obtained reaction mixture, and the process is conducted at 60 to 120oC in the adiabatic mode, when the molar ratio of butadiene and chlorine 1...3:1, and carbon tetrachloride take in quantity 4-9 moles per 1 mole of butadiene (ed. mon. The USSR 1022960, 1983).

The disadvantage of this method is the process at high temperature and in the presence of high-boiling solvent.

The aim of the invention is to develop an improved method for the selection of 1,4-dichlorobutene-2 without a preliminary rectification of the mixture of C4of hydrocarbons obtained by liquid-phase chlorination of butadiene.

This objective is achieved in that the mixture of C4-chlorohydrocarbons, obtained by liquid-phase chlorination of butadiene by known methods after removal of the applied solvents, l is the Christmas tree dehydrochlorination 30-46% aqueous NaOH at a temperature of 13-20oC in the environment of ethyl chloride in the presence of 0.3-0.8 wt.% to a mixture of C4-chlorohydrocarbons catalytic system consisting of trialkyl-1-harbutt-2-yl ammonium chloride and alcohol components ROH, where R is a C1-C4C6H5-CH2-or 1,4-butanediol obtained directly in a mixture of C4-chlorohydrocarbons preliminary introduction of appropriate trialkylamine and alcohol with maintaining the mixture at least one hour.

The method consists in the following.

In a reactor equipped with a stirrer, reflux condenser, cooled with running water, a long funnel and a thermometer, put the estimated amount of the mixture of chlorinated C4-hydrocarbons, prior to 1 hour enter 0.3 to 0.8 wt.% the mixture (preferably 0.5%) trialkylamine (triethyl-, tripropyl, tributylamine) and 1-5 moles to trialkylamine alcohol component ROH, where R = C1-C4C6H5-CH or 1,4-butandiol.

After that, the reactor was added ethyl chloride under his weight ratio to a mixture of C4-chlorohydrocarbons, equal 1-3:1 (preferably of 1.5:1).

With stirring the reactor was added the calculated amount of water 3 is doctitle 2:1), and tetrachlorobutane is equal to 4.2 to 4.5:1 (preferably a 4.3:1).

Boiling ethyl chloride (temperature = 13-20oC) through the condenser is sent to the collector where they are returned to the reactor. After addition of aqueous NaOH, the reaction mixture was stirred for further 0.5-1 hour.

Upon completion of the reaction in the reactor add demineralized water to dissolve the NaCl formed and the reaction mass is directed in Florentin. The organic phase is separated, add acetic acid until neutral and at a temperature of 20-40oC is subjected to azeotropic drying by removal of ethyl chloride.

After that VAT residue fractionary, highlighting first - chloropropene, then 2,3-dichlorobutadiene. Remaining in Cuba 1,4-dichlorobutene-2, which in the conditions of the reaction, not dihydrochloride, distilled in vacuum.

The advantage of the proposed method:

application to reaction dehydrochlorinating as solvent ethyl chloride, providing directional removal of HCl only from 3,4-dichlorobutene-1, trichloroethanol and tetrachlorobutane;

the absence of allocation of 1,4-dichlorobutene-2 resinous products under mild conditions fractionation;

no low energy consumption of the entire technology, including the allocation of 1,4-dichlorobutene-2;

obtaining catalytic system directly in a mixture of C4-chlorohydrocarbons, which coupled with ethyl chloride provides selective dehydrochlorination only 3,4-dichlorobutene-1, trichloroethanol and tetrachlorobutane.

The method is illustrated by the following examples:

Example No. 1. In a reactor equipped with heating and stirring device, a reflux condenser, a separating funnel and thermometer was placed 100 g of a mixture of C4-chlorohydrocarbons, obtained by the chlorination of butadiene in the environment ethyl chloride, composition:

1. 3,4-DHB - 68%

2. 1,4-DHB - 20%

3. CIS-1,4-DHB - 3%

4. Trichlorobutene - 3%

5. Tetrachlorobutane - 6%

6. Monochlorotoluene - 1%

Prior to placing the mixture in the reactor in her pre-added 0.7 g of triethylamine and 0.9 g of 1,4-butandiol, after which the mixture is incubated for one hour.

To a mixture of C4-chlorohydrocarbons in the reactor was added 150 g of ethyl chloride and with stirring was added for 0.5 hour at 60 g of NaOH in the form of a 46% aqueous solution. The temperature of the reaction mixture 13-20oC, wikipedi ethyl chloride through the fridge goes into the collection returned from ablaut demineralized water to dissolve the precipitated Sodium chloride and the reaction mass is placed in a separating funnel. The mixture defend 15 minutes, the organic layer separated. To the remaining organic layer was added 1 g of acetic acid until neutral and washed with 50 ml of demineralized water. The mixture defend 0.5 hour, the aqueous layer was separated, the organic phase is placed in a distillation flask equipped with a reflux condenser and a nozzle Dean-stark.

Distillation flask is heated on a water bath up to 20-40oC, wikipedi chloride ethyl going through the reflux condenser to be cooled in a brine collection. In the nozzle Dean-stark water gathers, a small number of chloropropene and dichlorobutadiene that after separation of the water combined with kovovymi.

After removal of all ethyl chloride remaining organic phase fractionary, selecting first - chloropropene, then dichlorobutadiene. VAT residue containing mainly 1,4-dichlorobutene-2, is distilled in vacuum.

Received: chloropropene 40 g of 2,3-dichlorobutadiene - 5 g of 1,3-dichlorobutadiene - 0.7 g, 1,4-dichlorobutene-2 - 22, the Output of 1,4-dichlorobutene-2 - 95% of which is contained in a mixture of C4-chlorophenolate.

Example 2. In the conditions of example No. 1 to a mixture of C4-chlorohydrocarbons previously added 0.5 g of tributylamine and 1.0 g of ethyl is similar mixture.

Example 3. In the conditions of example No. 1 to dehydrochlorinating taken 100 g of a mixture of chlorohydrocarbons composition:

1. 3,4-DHB - 43%

2. 1,4-DHB - 31%

3. CIS-1,4-DHB - 1%

4. Trichlorobutene - 8%

5. Tetrachlorobutane - 16%

6. Monochlorotoluene - 1%

Previously it was added 0.5 g of triethylamine and 0.8 g of benzyl alcohol. After dehydrochlorinating and fractional distillation of the obtained 29 g of 1,4-dichlorobutene-2, 30 g of chloropropene, 13 g of 2,3-dichlorobutadiene and 2 g of 1,3-dichlorobutadiene. The yield of 1,4-dichlorobutene-2 to 96.5% of theory.

Example 4. In the conditions of example 1 to a mixture of C4-chlorohydrocarbons added 0.8 g of triethylamine and 1.8 g of butyl alcohol (molar ratio of amine:alcohol is 1: 3) and 300 g of ethyl chloride (weight ratio of chloride:ethyl chloride = 1:3). Upon completion of the reaction and treatment of the organic phase allocated 97% of 1,4-dichlorobutene-2 contained in the original mixture.

Example 5. In the conditions of example No. 3 to 100 g C4-chlorohydrocarbons added 100 g of ethyl chloride (weight ratio of chloride:ethyl chloride = 1:1). After dehydrocorydaline, processing of the organic phase and rectification received 95% of 1,4-dichlorobutene-2 contained in the original mixture.

1. Way from what lorom using rectification, characterized in that the pre-mixture is subjected to selective water-alkaline dehydrochlorination 30 - 46% NaOH at boiling of the reaction mixture in the environment of ethyl chloride at a temperature of 13 - 20oC when his weight ratio to a mixture of C4-chlorohydrocarbons, equal to (1 - 3) : 1, preferably of 1.5 : 1, in the presence of 0.3 - 0.8 wt.% to a mixture of C4-chlorohydrocarbons catalytic system - triethyl-, tributyl-1-harbutt-2-yl-ammonium chloride and alcohol components ROH, where R = C1- C4C6H5CH2- or 1,4-butandiol when the molar ratio of the components of the catalytic system is equal to (1 - 5) : 1, followed by the separation of the organic phase, its neutralization, azeotropic drying with simultaneous removal of ethyl chloride and the allocation of individual-chloroprene, dichlorobutadiene and 1,4-dichlorobutene-2 rectification.

2. The method according to p. 1, characterized in that the catalytic system is prepared directly in a mixture of products of liquid-phase chlorination of butadiene by addition of an appropriate trialkylamine in the amount of 0.3 - 0.8 wt.% preferably 0.5 wt.% to a mixture of C4-chlorohydrocarbons and the corresponding alcohol components with maintaining this mixture at room temp 4-chlorohydrocarbons is carried out at a molar ratio of NaOH to 3,4-dichlorobutene-1 and trichlorobutene, present in the mixture equal to (1.8 - to 2.2) : 1, preferably 2 : 1, and tetrachlorobutane equal to (4,2 - 4,5) : 1, preferably 43 : 1, respectively.

 

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FIELD: organic synthesis catalysts.

SUBSTANCE: catalyst is prepared from allyl chloride production wastes comprising 30-50% 1,3-dichloropropenes, 30-60% 1,2-dichloropropane, and 3-5% 1,2,3-trichloropropane, which are treated at 5-10°C with 30-50% dimethylamine aqueous solution in such amount as to ensure stoichiometric ratio of dimethylamine with respect to 1,3-dichloropropenes. Resulting mixture is held at 20-25°C for 0.5-1.0 h and then 40-44 sodium hydroxide solution is added in stoichiometric amount regarding dimethylamine, after which clarified waste is added to dimethylamine at 60-70°C and stirring in amount ensuring stoichiometric ratio of dimethylamine to 1,3-dichloropropenes contained in clarified waste. Mixture is aged for 2-3 h, organic phase is separated, and remaining interaction phase is supplemented by C1-C4-alcohol or benzyl alcohol at alcohol-to-dimethylamine molar ratio 1:(1-3).

EFFECT: reduced expenses on starting materials.

2 cl, 3 ex

FIELD: chemical industry, in particular method for production of value monomer such as vinylchloride.

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EFFECT: method with high conversion ratio and selectivity.

3 cl, 2 ex

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