The method of vapor-phase hydrodechlorination of carbon tetrachloride
(57) Abstract:During hydrodechlorination in the gas phase carbon tetrachloride is used, the catalyst is platinum on aluminum oxide, which process the reaction mixture with the addition of 0.5 - 1.5 vol.% water vapor for 2 to 5 h at 60 - 120oC. After this treatment, by varying the concentration added to the reaction mixture of water vapor (up to 1 vol.%) direct the process of the priority obtaining or chloroform, or chloroform and chlorohydrocarbons, containing two carbon atoms. Thus alter the activity of the catalyst and the ratio of the reaction products. table 2. The invention relates to a method of carrying out catalytic processes, in particular to a method of changing the activity and selectivity of catalysts in the hydrodechlorination of carbon tetrachloride in the vapor phase.It is known (F. H. Weiss et al., J. Catal., 1971, V 22, p. 345, U.S. patent 3579596) that when the hydrogenation of carbon tetrachloride with hydrogen at 70 - 180oC on the catalyst is platinum on alumina" the main products are chloroform and methane:
CCl4+ H2= CHCl3+ HCl
CCl4+ 4H2= CH4+ 4HCl
Most proximity which is Yes way described in the patent (U.S. patent 5097081). According to this patent, to modify the activity and selectivity of the hydrodechlorination of carbon tetrachloride, the reaction is carried out in the presence of oxygen or oxygen-containing gas (in the above examples used the air). As catalysts are encouraged to apply noble metals or metals of subgroups of copper deposited on the aluminum oxide or titanium (in the examples used in the catalyst of 0.5 wt.% Pt on alumina). From the data presented in the examples of the patent, additives air in quantities of up to 4.5 vol.% in the original gas-vapor mixture of hydrogen with carbon tetrachloride (molar ratio of these substances about 8) leads to an increase in activity (characterized by the conversion and the performance of the catalyst and reduce the selectivity of the formation of perchloroethylene and hexachlorethane. After cessation of air activity of the catalyst decreased and the selectivity of education chlorohydrocarbons C2grew from less than 1% to .8%.The disadvantages of this method include the need to add oxygen (or air) to the stream containing hydrogen, the result of which can form explosive with the R fails if necessary to carry out the process in the direction of the predominant obtain chlorohydrocarbons C2.The objective of the invention is such a method of conducting the process in which the catalyst activity and the ratio of the reaction products can be varied within wide limits, in particular to achieve preferential receipt of chlorohydrocarbons C2and to avoid the disadvantages of the prototype associated with mixing of streams containing hydrogen and oxygen.The above objective is achieved by treatment for 2 to 5 h at 60 - 120oWith catalyst reaction mixture containing 0.5 to 1.5 vol.% water vapour.The catalyst was prepared by the following method.The carrier of active alumina with a specific surface area of 210 sq m on g is used in the form of extrudates with a length of 3 to 5 mm and a diameter of 3 mm at the Beginning of 43.3 g of this carrier was progulivali in air at a temperature of 500oWith, then soaked in water holding capacity of 34.4 ml of an aqueous solution hloristovodorodnykh acid containing 0.037 g Pt/ml Impregnated granules kept in a closed container for 3 days, then dried at 130oC for 4 h Then the sample was reduced by hydrogen for 4 h at 460 - 480oC. the thus Prepared catalyst was not in contact with getcatalog used a glass U-shaped tube with a diameter of 5 mm Catalyst loading in all experiments was 0,93 gThe nature of the influence of water vapor on the reaction of hydrodechlorination of carbon tetrachloride illustrate the examples below.Example 1 (for comparison). The reactor was loaded catalyst and at a temperature of 80oC it was filed 0,6 IO vapor of carbon tetrachloride and 4.2 nl of hydrogen per hour.Under these conditions, the conversion of carbon tetrachloride 0,08 when the molar izbirateljnostj education chloroform, methane and chlorohydrocarbons C2(mainly trichloroethane) of 0.65, respectively, 0,098 and 0.25.Example 2. In the reaction mixture of example 1 at 80oC for 5 h was added to 0.05 nl of water vapor per hour (which corresponds to its concentration in the initial mixture of 1,1 vol.%).Continued experience, stopping the flow of water vapor. Within 5 h, the conversion was in the range of 0.49 - 0,515 when izbirateljnostj on the above products 0,82 - 0,835, 0,15 - 0,17 and 0.008 - 0.01 respectively.Newly added to the source gas-vapor mixture of 0.05 nl of water vapor per hour. Within 5 hours the conversion was varied in the range of 0.066 - 0,071 and selectivity of 0.42 to 0.44, 0,041 - 0,047 and 0,53 is 0.55, respectively.Again pricolo of 0.005, respectively.These examples show that the treatment with water vapor added to the source gas-vapor mixture supplied to the newly restored catalyst, leads to a significant change in its properties in the hydrodechlorination of carbon tetrachloride, namely, in the absence of water vapor treated in this way the sample is more active and selective in relation to the formation of chloroform and methane than newly restored, and in the presence of steam at almost the same activity more selective in terms of education hydrocarbon, C2.Further examples illustrate the effect of pre-processing newly restored sample of catalyst and holding it then hydrodechlorination of carbon tetrachloride on process performance. In all these examples (which presents part of the results of the study) after treatment of the catalyst the reaction mixture of 0.6 nl/h CCl44.2 nl/h of hydrogen) with the addition of water vapor under the conditions shown in table. 1, at first for 5 h, the reaction was carried out in the absence of water vapor in the source gas mixture, and then 5 h in the presence (PL. 2). < / BR>1. Weiss, F. H., Gambhir, B. S., Leon, R. B. J. Catal. 22, 345, (1971).2. US Patent N 3579596
3. US Patent N n The method of vapor-phase hydrodechlorination of carbon tetrachloride in the presence of a catalyst of platinum on alumina" at 40 - 180oC, wherein the catalyst is treated with the reaction mixture with the addition of 0.5 - 1.5 vol.% water vapor at 60 - 120oC for 2 to 5 h, and then the process is carried out at concentrations of water vapor up to 1 vol.%.
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