The method of vapor-phase hydrodechlorination of carbon tetrachloride
(57) Abstract:The invention relates to the production of chlorinated derivatives of methane, ethane, ethylene catalytic hydrochloridebuy of carbon tetrachloride. The process is conducted in the vapor phase using a platinum catalyst on the carrier. As a carrier of the active component - platinum use of diamond-like substance. Selectivity for compounds C2above is 2 to 8 times compared with known methods. table 1. The invention relates to a method of catalytic hydrodechlorination of chlorinated organic compounds. More specifically, it relates to a method of hydrodechlorination of carbon tetrachloride on platinum catalysts, representing the deposited platinum.Products hydrodechlorination of carbon tetrachloride on platinum catalysts are compounds C1mainly chloroform and methane, and connections C2mainly chlorinated derivatives of ethylene and ethane. Known methods of hydrodechlorination of carbon tetrachloride, for example, US patent 3 579 596, US atent 5 146 013, US patent 5 081 097), are characterized by a significantly higher selectivity for compounds C1, Cano close to 100%, and in the patent (US patent 5 081 097), selected as a prototype, the catalyst is platinum on alumina, this figure is reduced to only 80%, i.e., the selectivity of the formation of compounds C2does not exceed 20%.The aim of the present invention is to provide a method for hydrodechlorination of carbon tetrachloride on platinum catalysts, providing higher in comparison with the known methods, the selectivity of the formation of compounds C2having a practical interest. The objective is achieved by deposition of platinum on a carrier of diamond-like substances (RF patent 2051093, BI, 1995 No. 36, S. 201), providing the necessary degree of oxidation of the catalyst surface and dispersion of platinum.As a diamond-like substance used diamond nanopowder (A. M. Staver, A. I. the Lyamkin, N. In. Gubareva, E. A. Petrov. The way to obtain diamonds. Auth. mon. THE USSR, N 1165007 (01. 07. 82), A. I. the Lyamkin and other Receiving diamonds from explosives. DAN SSSR, 1988, I. 302, No. 3, S. 611-613), resulting from the detonation of explosive mixtures of TNT with RDX in a 1: 1 ratio in the blast chamber filled with carbon dioxide. The nanopowder separated from the condensed carbon is Alenia non-diamond forms of carbon and metallic impurities.Physico-chemical properties of diamond-like substances characterized by a set of analytical techniques, including x-ray analysis, spectroscopy Raman scattering, spectroscopy electron paramagnetic resonance, mass spectrometry and electron microprobe elemental analysis, infrared spectroscopy. The samples represent carbon dielectric material with a crystalline structure of diamond. The average crystallite size of 4 nm. The specific surface of the powder - 280 m2/, Content of non-diamond forms of carbon not more than 5 wt.%. The composition of the diamond-like substance composed of oxygen up to 10%, the nitrogen and hydrogen to 1%, other impurities - a total of up to 2%. Its main differences from other diamond-like carbon substances subject to the specifics of the detonation synthesis and lie in the small size of the crystals, defects in their structure and the presence of surface functional cover defining surface activity, in particular, tightly-coupled surface groups, C-O, which are stable up to temperatures of 700oC.The catalyst was prepared by mixing nanopowder of diamond-like substance with an aqueous solution of charitablecardonation the behaviour of the catalyst was carried out on running cellophane glass installation. The reactor was heated in an air thermostat. Before the beginning of experiments freshly loaded catalyst was reduced by hydrogen directly in the reactor at 450oC.Hydrogen was purified using a palladium membrane. Carbon tetrachloride was filed in the installation, saturating them with hydrogen in the saturator.Analysis of the reaction products was carried out by the methods of gas chromatography and volumetric titration.Example 1. 15 g Nanopowder slaboionizovannogo diamond-like substances (broadened line on the radiograph when d = 0,205 nm, the average crystallite size of 3.8 nm, broadened line 1328 cm-1in the spectra of CU) containing point defects and dislocations (intense singlet with g-factor 2.00 and H = 8 GS in the spectrum EPR) and surface CO-group with a characteristic frequency of vibration of C= O bond (intensive line 1880 cm-1in the IR spectra, the concentration of group - 8 wt.% oxygen), were mixed in a mortar with 25 ml 0,0069 molar aqueous solution hloristovodorodnykh acid (platinum concentration of 2.34 g/l) to form a paste. The resulting paste was extrudible through the metal syringe with a diameter of Spinneret 3 mm extrudates were dried in air at room temperature for 20 h, and then in susil the Torah - 0.39 wt.%.Example 2. 7,89 g (15 cm3) Of the catalyst prepared as described in example 1 were loaded into eraksoy reactor (diameter 20 mm) with a Central pocket for thermocouples (diameter 4 mm) was heated in a stream of hydrogen (5 nl/h), 450oC and kept under these conditions for 4 hours and Then the reactor was cooled to 150oC and reduced total flow of hydrogen to 4.2 nl/h In this part of the hydrogen (1,68 nl/h) on the way to the reactor was saturated vapors of carbon tetrachloride (of 0.6 nl/h).The reaction mixture was 4.2 nl/h of hydrogen and 0.6 nl/h of carbon tetrachloride was carried out at 150 and 80oC. the Results of these tests are shown in table.Example 3. For comparative tests of the preparation of the catalyst used well-known carrier - aluminum oxide with a specific surface area of 200 m2/g immediately before use calcined in air at 550oC for half an hour.13,62 g of a Carrier in the form of extrudates with a diameter of 3 mm was soaked in water holding capacity of 2.2 N. hydrochloric acid solution hloristovodorodnykh acid (platinum concentration 0,0038 g/ml). The impregnated pellets were kept in closed containers within four days. Then four hours was dried in a drying Cabinet at 130ooC and expenses of the initial reactants, hydrogen and carbon tetrachloride - 4,2 and 0.6 nl/h, respectively. The results presented in the table.From the comparison of the results in examples 2 and 3, it follows that the proposed method significantly (2-8 times) to increase the selectivity of the process for compounds C2. The method of vapor-phase hydrodechlorination of carbon tetrachloride in the presence of platinum catalyst on a carrier, characterized in that as the carrier of the use of diamond-like substance.
FIELD: industrial organic synthesis.
SUBSTANCE: invention is dealing with production of chlorohydrocarbons exhibiting plasticizing properties in polymer compositions in production of synthetic building materials, varnishes and paints, artificial films and leathers, in rubber industry, and as fire-retardant additives in polymers. Process comprises chlorination of waste obtained in production of C14-C32 fraction by ethylene-α-olefin oligomerization. Chlorination is accomplished in two steps: addition chlorination at 35-55°C followed by substitution chlorination at 40-105°C. Chlorohydrocarbons thus obtained can, in particular, be used as secondary plasticizer in polyvinylchloride compositions.
EFFECT: reduced expenses due to using production waste.
4 tbl, 30 ex
SUBSTANCE: invention relates to a method of obtaining 1,1-difluorochloroethanes of formula CF2Cl-CHnCl3-n, where n=0-3, including the gas-phase interaction of 1,1-difluoroethane with chlorine at a higher temperature in the presence of a fluorine-containing initiator and diluents, washing from inorganic products, condensation of organic products and separation of target products by rectification. The method is characterised by an application of 1,1-difluoroethylene as an initiator and 1,1-difluoroethane or 1,1-difluoroethane in a mixture with compounds of formula CF2X-CHnCl3-n, where X=H or Cl, n=1-3 as a diluent.
EFFECT: application of the claimed method makes it possible to obtain simultaneously two or more 1,1-dichloroethanes with high raw material conversion and high selectivity by products.
5 cl, 4 tbl, 6 ex
FIELD: chlororganic chemistry.
SUBSTANCE: invention relates to hydrochlorination catalyst containing aluminum η-oxide, doped with cesium chloride. Also method for methanol hydrochlorination in vapor phase using claimed catalyst is disclosed.
EFFECT: decreased selectivity to dimethyl ether and inhibited coke deposition on working catalyst.
16 cl, 6 tbl, 1 dwg, 20 ex
FIELD: chemical industry, in particular method for production of value products from lower alkanes.
SUBSTANCE: claimed method includes passing of gaseous reaction mixture containing at least one lower alkane and elementary chlorine through catalytic layer. Used catalyst represents geometrically structured system comprising microfiber with diameter of 5-20 mum. 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 of increased yield.
3 cl, 4 ex
FIELD: organic chemistry, chemical technology.
SUBSTANCE: invention relates to processes for the oxidative halogenation reaction of hydrocarbons, in particular, for synthesis of haloidmethanes, their following processing to value chemical compounds. Method involves contacting methane, halogenated methane or their mixture with halogen source and oxygen source in the presence of catalyst to yield halogenated C1-hydrocarbon having more amount of halogen substitutes as compared with the parent hydrocarbon, Process is carried out at temperature above 200°C but less 600°C and under pressure 97 kPa or above but less 1.034 kPa and at the volume rate of raw feeding above 0.1 h-1 but less 100 h-1. Catalyst comprises rare earth metal halide or oxyhalide no containing iron and copper. The atomic ratio of rare-earth element to iron or copper exceeds 10:1 under condition that if catalyst comprises cerium in the amount less 10 atomic percent of the total amount of rare-earth components then catalyst comprises also one additional rare-earth element. Reacting hydrocarbon is chosen from the group consisting of methane, chloromethane, bromomethane, iodomethane, dichloromethane, dibromomethane, diiodomethane, chlorobromomethane and their mixtures. The molar ratio of hydrocarbon to halogen is above 1;1 but less 20:1 and that to oxygen is above 2:1 but less 20:1. The reaction mixture comprises additionally a diluting agent as nitrogen, helium, argon, carbon monoxide or dioxide or their mixtures. Formed methyl chloride or methyl bromide can be fed to the hydrolysis step to yield methyl alcohol or used in process of catalytic condensation to form light olefins and/or gasolines. It is possible contacting methyl halide with the condensation catalyst to form ethylene and the following preparing vinyl halide monomer, for example, vinyl chloride or acetic acid under carbonylation conditions. Invention provides enhancing output of the process at the expense of using the effective modified catalyst based on rare-earth elements.
EFFECT: improved halogenation method.
33 cl, 1 tbl, 1 ex
FIELD: industrial organic synthesis.
SUBSTANCE: process involves interaction of carbon tetrachloride with methanol in gas phase at elevated temperature in fixed-bed reactor accommodating two heterogeneous contact beds with different active ingredient concentrations, said active ingredient being zinc chloride deposited on solid carrier. Process can be carried out in presence of hydrogen chloride and/or water additives.
EFFECT: increased specific output of the process and lifetime of catalyst.
1 dwg, 3 tbl, 7 ex
SUBSTANCE: invention concerns method of obtaining methyl chloride by selective catalytic chlorination of methane, involving throughput of a source reaction gas mix containing at least methane and chlorinating agent in the form of either elementary chlorine or a mix of chlorine hydride with oxygen, through at least one catalyst layer. At that, the catalyst features additionally active centres with increased acidity and deuterium/hydrogen exchange depth not less than 10% at the temperature of 350-355°C in the deuterium and hydrogen mix containing 0.6% of hydrogen, 0.6% of deuterium, 0.05% Ar and 98.75% nitrogen, at the volume deuterium-hydrogen mix feed rate of 20000 hours-1 in the thermal regulated reaction mode at the heating rate of 10 K/minute. Active catalytic component is either platinum or copper, or silver. Catalyst carrier is microfibre of diametre of 1 to 20 micron, which can be structured in either non-woven or pressed material similar to wad or felt, or fibre of diametre of 0.5-5 mm, or woven material with lattice similar sateen, canvas, or openwork, with weave diametre of 0.5-5 mm.
EFFECT: high activity and selectivity of methane chlorination to methyl chloride at lower temperatures without production of polychlorinated hydrocarbons.
6 cl, 6 ex
SUBSTANCE: catalyst contains zinc chloride and carrier - porous granulated carbon-carbonic composition material based on pyrocarbon and nanodispersed carbon with specific surface by "БЭТ" 350-650 m2/g and total pore volume by water 0.55-0.85 cm3/g. Described is method of preparation of catalyst described above, which is prepared by impregnating carrier with water or hydrochloric acid solution of zinc chloride in two stages: zinc chloride sorption by carrier from water solution at temperature 15-25°C and evaporation of remaining part of solution at temperature 80-100°C. Also described is process on obtaining methylchloride by catalytic hydrochlorating of methanol, which is carried out in continuous reactor at temperature 140-200°C and contact time 0.6-1.11 s in presence of described above catalyst.
EFFECT: complete methanol conversion and complete selectivity to methylchloride.
7 cl, 6 ex, 4 dwg
SUBSTANCE: proposed method of producing chloromethanes involves gas-phase thermal chlorination of methane, condensation of obtained chloromethanes, removal of methyl chloride from the condensate, obtaining a mixture of chloromethanes, distillation of this mixture with separation of the light fraction, liquid-phase chlorination of the light fraction with photochemical initiation, combination of vat fractions with products of liquid-phase chlorination, and separation of individual chloromethanes using known methods.
EFFECT: reduced formation of tetrachloromethane and increased selectivity on chloroform.
2 cl, 1 tbl, 4 ex
SUBSTANCE: invention relates to a method of converting organochloride wastes containing tetrachloromethane to methyl chloride by reacting organochloride wastes with methanol at high temperature in a gas phase in a cascade consisting of at least two series-connected reactors, by periodically redistributing the stream of the initial mixture to the cascade reactors. All reactors have at least two heterogeneous contact layers with different concentration of the active ingredient which is zinc chloride deposited on a solid support. The process is preferably carried out in the presence of hydrogen chloride additive and/or water.
EFFECT: longer service life of catalyst.
2 cl, 2 dwg, 1 tbl, 5 ex
SUBSTANCE: invention relates to catalytic methods of processing methane through direct and/or oxidative chlorination. For oxychlorination of methane, hydrogen chloride is taken in volume ratio to methane equal to 0.5-1:1, oxygen is taken in total volume ratio to hydrogen chloride in the range of 0.58-0.68:1 and at the oxidative chlorination step of the process in mass ratio of 3.5-4:1 to unreacted hydrogen chloride. Water is added, through which unreacted hydrogen chloride in the composition of the formed hydrochloric acid is returned into the process to the methane oxychlorination step. The process also includes the following steps: pyrolysis of methyl chloride obtained at the methane chlorination and/or oxychlorination step to obtain lower olefins, mainly ethylene, oxidative chlorination of the obtained ethylene to dichloroethane, thermal dehydrochlorination of the obtained dichloroethane to vinyl chloride. The catalyst for direct and/or oxidative chlorination of methane used is a mixture of copper, potassium and lanthanum chlorides in molar ratio of 1:1:0.3, deposited in amount of 3-30 wt % on a porous support with specific surface area of 1-60 m2/g. Pyrolysis of methyl chloride is carried out in a reactor with a fluidised bed of a silicoalumophosphate catalyst of the SAPO-34 type at pressure of 2-5 atm and temperature of 400-500°C.
EFFECT: design of a chlorine-balanced method of processing natural gas to obtain methyl chloride, lower olefins, mainly ethylene, dichloroethane and vinyl chloride.
7 cl, 1 dwg, 1 ex
SUBSTANCE: methyl chloride synthesis method involves reacting methanol with hydrogen chloride in a synthesis reactor to obtain a vapour-gas mixture containing methyl chloride, and extraction of methyl chloride from vapour-gas mixture via partial condensation, followed by washing with initial methanol which is then fed into the synthesis reactor, and distillation purification where methyl chloride is extracted in form of a distillate. The initial methanol is fed into the system in three streams, wherein a stream A is fed for washing, stream B is fed for distillation purification and the remaining stream C is fed directly into the synthesis reactor. The ratio of stream A to the overall stream (A+B+C) of the initial methanol is between 0.1 and 0.5; the ratio of stream B is between 0.3 and 0.7; the ratio of stream C is between 0.05 and 0.5.
EFFECT: highly efficient process owing to avoiding recycling the desired product into the synthesis reactor.
5 cl, 1 dwg, 2 ex