The method of producing vinyl chloride
(57) Abstract:The invention relates to a method for producing vinyl chloride, used for various polymeric materials. The invention consists in that the vinyl chloride receive thermal dehydrochlorination of dichloroethane at a temperature of 250-550oC and a pressure of 20-30 bar, followed by quenching of the reaction gases 5 wt. %. The solution in dichloroethane bifunctional catalyst-hydrochloride amine of General formula
where R is alkyl, isoalkyl or aryl.Reach conversion dichloroethane to 99% with a selectivity of formation of vinyl chloride 98,5-99,0%. table 1. The invention relates to petrochemical synthesis, and in particular to a method for producing vinyl chloride, one of the most important chloroethanol used for various polymeric materials (Khrulev C. M. "Polyvinyl chloride".- M.: Izd. In chemistry, 1964, S. 18-28).A known method of producing vinyl chloride by dehydrochlorination of dichloroethane treatment in aqueous alkali in the presence of methanol (U.S. Pat. USA, 2541022 (1951).The dehydrochlorination is carried out with 50% aqueous-methanol solution of sodium hydroxide at temperaturereading process;
the use of expensive methanol and caustic soda.Currently, the global industrial practice in the vast majority of developed thermal dehydrochlorination of dichloroethane at a temperature of 400 to 500oC. (Ed. St. USSR N 218880, publ. 12.11.71, BI N 8, and the Production of vinyl chloride in the major capitalist countries", obsorn. inform. the series Chlorine industry) niitekhim, 1979, S. 24).The prototype of the invention is a method of producing vinyl chloride, which consists in the fact that the purified dichloroethane is evaporated and sent to thermal dehydrochlorination, which is carried out at 250 - 550oC and pressures up to 30 atmospheres in the presence of initiators or without them. Conversion of dichloroethane is 42-70% (production Process regulations of vinyl chloride Sterlitamak JSC "Kaustik", 1996, N 69-96).As a rule, to reduce the formation of coke in the tubes of the reactor under industrial conditions, the conversion is maintained at 50%. The selectivity to vinyl chloride is 97-98,5%. Implemented gases with a temperature of 250-550oC subjected to quenching by water quenching column cooled by circulating dichloroethane.A disadvantage of the known. Opredelenie hydrocarbons (acetylene, butadiene) is called reinforced resin and soot build - up, corrosion and sakakawea equipment. The presence of acetylene increases the hazard process.Further, the reaction products from the stage of thermal dehydrochlorination separated by distillation and subjected to special treatment. Unreacted dichloroethane allocate and re-injected into the zone of thermal dehydrochlorination.The task of the invention is to increase the selectivity of the process.The problem is solved by thermal dehydrochlorination dichloroethane at 250-550oC and a pressure of 20-30 bar, followed by quenching of the reaction gases in the presence of a hardening liquid bifunctional catalytic complex - hydrochloride amine of General formula
where R is alkyl, isoalkyl or aryl in various combinations.In the presence of the specified bifunctional catalytic complex of the unreacted dichloroethane is an additional dehydrochlorination with the formation of vinyl chloride. The mixture of acetylene by means of a bifunctional catalyst is subjected to hydrochloridebuy to the target product.InvestoC. While the removal of hydrogen chloride is not observed.In the inventive object, we managed to achieve the opposite effect: hydrochloride amines otscheplaut hydrogen chloride. This can be explained by the manifestation of the basic properties of hydrochloride tertiary amines, so the connection can koordinirovat molecule of HCl. The resulting bifunctional catalytic complex, especially at high temperatures, contributes to the reaction hydrochlorination of acetylene. If the content of acetylene in the reaction medium is low, the complex decomposes with evolution of HCl and the source of the amine hydrochloride.Thus, the claimed technical solution is not obvious, because it is based on the ability of the amine hydrochloride to split hydrogen chloride.The method consists in the following.Pre-purified 1,2-dichloroethane with the content of the basic substance is not less than 99.9 wt.% evaporated and fed into the reactor, which are subjected to thermal dehydrochlorination at a temperature of 250-550oC and a pressure of 20-30 bar. The reaction gases are subjected to the subsequent hardening chilled dichloroethane containing 5 wt.% bifunctional catalyst in 148-153
Dichloroethane - 33,23 g (0.52 mol);
including unreacted dichloroethane - 1.98 g (0.02 mol);
The vinyl chloride - 60,35 g (0,9658 mol);
and other impurities - 1.42 g
Thus, the total conversion of dichloroethane for passage 98%, selectivity 98,54%.Example 2. Analogously to example 1 as the catalyst used hydrochloride diethylamine.Example 3. Analogously to example 1 as the catalyst used hydrochloride cyclohexylamine.Example 4. Analogously to example 1 as the catalyst used hydrochloride diethylaniline.Example 5. Analogously to example 1 as the catalyst used hydrochloride diethylpropion.Example 7. Analogously to example 1 as the catalyst used hydrochloride diethylethanolamine.Example 8. Analogously to example 1 as the catalyst used hydrochloride Diisopropylamine.The results of the examples are summarized in table.The process of the proposed method increases the conversion of dichloroethane to 99 wt.%, when selectivity 98,54-99,01%, reduces the output side, easily polymerized impurities of acetylene and butadiene, reduces almost twice the energy loss associated with the recycling of dichloroethane. The method of producing vinyl chloride by thermal dehydrochlorination of dichloroethane at a temperature of 250 - 550oWith subsequent quenching of the reaction gases circulating dichloroethane and the selection of the target product by distillation, characterized in that the quenching of the reaction gases is provided by 5 wt.% the solution in dichloroethane bifunctional catalyst hydrochloride amine of General formula
where R is alkyl, isoalkyl or aryl.
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.
SUBSTANCE: claimed method includes passing of reaction mixture containing dichloroethane vapor trough catalytic layer providing dehydrochlorination of dichloroethane to vinylchloride. Catalyst has active centers having in IR-spectra of adsorbed ammonia absorption band with wave numbers in region of ν = 1410-1440 cm-1, and contains one platinum group metal as active component, and glass-fiber carrier. Carrier has in NMR29Si-specrum lines with chemical shifts of -100±3 ppm (Q3-line) and -110±3 ppm (Q4-line) in integral intensity ratio Q3/Q4 from 0.7 to 1.2; in IR-specrum it has absorption band of hydroxyls with wave number of ν = 3620-3650 cm-1 and half-width of 65-75 cm-1, and has density, measured by BET-method using argon thermal desorption, SAr = 0.5-30 m2/g, and specific surface, measured by alkali titration, SNa = 10-250 m2/g in ratio of SAr/SNa = 5-30.
EFFECT: method with high conversion ratio and selectivity.
3 cl, 2 ex
FIELD: industrial organic synthesis.
SUBSTANCE: gas-phase thermal dehydrochlorination of 1,2-dichloroethane is conducted in presence of hydrogen chloride as promoter dissolved in feed in concentration between 50 and 10000 ppm.
EFFECT: increased conversion of raw material and reduced yield of by-products.
4 cl, 1 tbl, 8 ex
FIELD: chemistry of organochlorine compounds, chemical technology.
SUBSTANCE: method involves treatment of 1,1,1-trichloro-2,2-bis-(4-chlorophenyl)-ethane with solid calcium hydroxide or a mixture of solid calcium hydroxide and solid sodium hydroxide with the content of sodium hydroxide in mixture 30%, not above, in the molar ratio 1,1,1-trichloro-2,2-bis-(4-chlorophenyl)-ethane to alkali = 1:(1.5-1.75) at heating in the presence of catalyst. As catalysts method involves benzyltrialkyl ammonium halides, preferably, benzyltriethyl ammonium chloride or benzyltrimethyl ammonium bromide, tetraalkyl ammonium halides, preferably, tetrabutyl ammonium bromide taken in the amount 0.0005-0.005 mole. Invention provides the development of a new method for preparing 1,1-dichloro-2,2-bis-(4-chlorophenyl)-ethylene allowing to enhance ecological safety of technological process and to improve quality of the end product.
EFFECT: improved method preparing.
2 cl, 15 ex
FIELD: organic chemistry, chemical technology.
SUBSTANCE: invention relates to a method for preparing vinyl chloride monomer and to a catalyst sued in catalytic preparing vinyl chloride monomer from flows comprising ethylene. Method for preparing vinyl chloride from ethylene is carried out by the oxidehydrochlorination reaction. Method involves combining reagents including ethylene, the source of oxygen and chlorine in the catalyst-containing reactor at temperature 350-500°C and under pressure from atmosphere to 3.5 MPa, i. e. under conditions providing preparing the product flow comprising vinyl chloride and ethylene. Catalyst comprises one or some rare-earth elements under condition that the atomic ratio between rare-earth metal and oxidative-reductive metal (iron and copper) is above 10 in the catalyst and under the following condition: when cerium presents then the catalyst comprises additionally at least one rare-earth element distinctive from cerium. Ethylene is recirculated from the product flow inversely for using at stage for combining reagents. Invention proposes a variant for a method for preparing vinyl chloride. Also, invention proposes variants of a method for catalytic dehydrochlorination of raw comprising one or some components taken among ethyl chloride, 1,2-dichloroethane and 1,1,2-trichloroethane in the presence of catalyst. Catalyst represents the composition of the formula MOCl or MCl3 wherein M represents a rare-earth element or mixture of rare-earth elements taken among lanthanum, cerium, neodymium, praseodymium, dysprosium, samarium, yttrium, gadolinium, erbium, ytterbium, holmium, terbium, europium, thulium and lutetium. The catalytic composition has the surface area BET value from 12 m2/g to 200 m2/g. Invention provides simplifying technology and enhanced selectivity of the method.
EFFECT: improved conversion method.
61 cl, 8 tbl, 32 ex