The way to obtain 1,1,2,2-tetrafluoroethane
(57) Abstract:The invention relates to the chemical industry and can be used to obtain 1,1,2,2-Tetrafluoroethane (HFC 134), which is promising the ozone destruction. The method comprises the catalytic hydrogenation of tetrafluoroethylene at elevated temperature, preferably 160-250oC. the Process is carried out under adiabatic conditions. Source tetrafluoroethylene served on hydrogenation in a mixture with indifferent diluent, for example, HFC 134, and the molar ratio of refrigerant 134 - tetrafluoroethylene maintained within the range of 1 - 6. The molar ratio of hydrogen - tetrafluoroethylene support in the range of 0.9 to 1.2. As the catalyst used palladium deposited on an alpha alumina (corundum), preferably industrial catalyst APK-2. For igniting the catalyst of the initial gaseous mixture is pre-heated at least to the 50oC. the Method is characterized by a high yield of the desired product (99 %) and negligible formation of undesirable by-products 1,1,2-triptorelin and hydrogen fluoride, which is confirmed by laboratory experiments. 4 C.p. f-crystals, 1 table. The invention relates to the organization of topicnum the halon.A method of obtaining 1,1,2,2-Tetrafluoroethane together with 1,1,2-triptoreline by catalytic hydrogenation of tetrafluoroethylene over restored oxide of Nickel. During the reaction the temperature is maintained at 150oC. the Total yield of these products is 75% 
A significant drawback of the known method of obtaining 1,1,2,2-Tetrafluoroethane is the low yield of the target product and the formation of 1,1,2-triptorelin as a by-product. The latter does not find practical application and requires the creation of installation for its neutralization, since the reset of the compounds in environmentally unacceptable. Causes complications and maintain the desired process temperature, since the reaction of hydrogenation of tetrafluoroethylene exothermic.The problem solved by the present invention is to improve the environmental parameters and the increase in the efficiency of production of 1,1,2,2-Tetrafluoroethane by reducing by-products of the hydrogenation of tetrafluoroethylene and reduction of specific energy consumption.The problem is solved in that in the method of obtaining 1,1,2,2-Tetrafluoroethane by hydrogenation of tetrafluoroethylene in the presence of catalunan as a catalyst of palladium on alpha-aluminum oxide, when filing the original of the tetrafluoroethylene to hydrogenation in a mixture with indifferent diluent at molar ratio indifferent diluent and tetrafluoroethylene, equal 1-6:1.In addition, as the catalyst is used preferably industrial alumina-palladium-based catalyst composition, wt. palladium 1,8-2; alumina rest.As indifferent diluent used is preferably 1,1,2,2-Tetrafluoroethane.The process is conducted at a molar ratio of hydrogen and tetrafluoroethylene is preferably in the range of 0.9 to 1.2:1.The process is conducted with the use of preheating of the catalyst by the filing of the original gaseous mixture, heated at least to the 50oC.Example 1. Hydrogenation of tetrafluoroethylene carried out in a laboratory setup, which includes a reactor made of Nickel with a diameter of 18 and a length of 250 mm, the dosing system of tetrafluoroethylene, hydrogen and gaseous diluent, and condensation products of hydrogenation. The reactor is equipped with a socket for thermocouple and an insulating jacket to prevent heat loss into the environment. Charged to the reactor industrial alumina-palladium catalyst brand APK-2 (TU . The catalyst pre-dehydration in a stream of nitrogen at 350oC for 5 h and restore in a stream of hydrogen at 300oC for 3 hours Pre-heating of the catalyst is carried out by the filing of the original gaseous mixture, heated in factographical established immediately before the reactor. Factographical is a hollow Nickel tube with a diameter of 10 and a length of 300 mm, supplied with external electric heating. The temperature in factographical set in the range of 50-100oC. After establishing the temperature in the reactor over 50oWith formadores disable the hydrogenation process is carried out in adiabatic conditions, continuing the supply of the initial reagents (tetrafluoroethylene and hydrogen) and diluent without preheating. The products of hydrogenation is removed from the reactor, washed with water for cooling and removal of trace quantities of acid components, dried digidrirovanny calcium chloride, condensed in the cylinder, cooled by liquid air, rectificatum laboratory low-temperature column efficiency 40 so so the Duration of the experiment 5 hours, the feed Rate of tetrafluoroethylene and hydrogen at 1 l/h (0.045 mol/h); 1,1,2,2-Tetrafluoroethane - 6 l/h (0,268 Mona and 138 g of 1,1,2,2-Tetrafluoroethane. As a result of condensation obtained 162 g of raw product from which, by low-temperature rectification allocated 161 g of 1,1,2,2-Tetrafluoroethane with a basic substance content of more than 99% 23 g of this amount synthesized in the course of this experience. The yield of the target product from theoretically possible for organic raw materials 94,0%
Examples 2 to 9. Experiments on the hydrogenation of tetrafluoroethylene performed with the setup described in example 1 with the same sequence of operations. Examples 2-5 were conducted under optimal conditions, examples 6-9 to justify the boundary conditions of the optimal mode. The specific conditions and the results of the experiments in all the examples presented in the table.As can be seen from the table, the implementation of hydrogenation under optimal conditions (examples 1-5) is characterized by the almost complete conversion of the starting materials and the high yield of the target product. Reducing the molar ratio of 1,1,2,2-Tetrafluoroethane to the tetrafluoroethylene below 1 results in adiabatic conditions to the uncontrolled growth temperature, which in turn is accompanied by formation along with the target product side, in particular triptorelin and 1,1,2-triptorelin (example 6). Increase the specified relation over 6 impractical to tetrafluoroethylene below 0.9, as well as the increase over 1.2 leads to incomplete conversion of the starting reagents, which in turn leads to increased consumption of reagents and the resulting decrease of the yield of the target product (examples 8 and 9).The presented examples demonstrate the effectiveness of the proposed method in comparison with the known. The effect can be explained as follows. Exothermic hydrogenation of tetrafluoroethylene prototype accompanied by the local overheating because the heat effect hydrogenation of tetrafluoroethylene extremely high (65 kcal/mol). Local overheating leads to the decomposition of 1,1,2,2-Tetrafluoroethane with the formation of triptorelin and hydrogen fluoride. The resulting triptorelin in terms of the prototype hereroense to 1,1,2-triptorelin. Adiabatic conditions the proposed method eliminates overheating and decomposition of 1,1,2,2-Tetrafluoroethane with the formation of triptorelin, hydrogen fluoride and 1,1,2-triptorelin. Thanks to improved environmental parameters of the process, increases the efficiency of production of 1,1,2,2-Tetrafluoroethane. 1. The way to obtain 1,1,2,2-Tetrafluoroethane by hydrogenation of tetrafluoroethylene in the presence of a catalyst at elevated temperature, otlichayushiesya palladium on alpha-aluminum oxide, when filing the original of the tetrafluoroethylene to hydrogenation in a mixture with indifferent diluent at a molar ratio indifferent diluent and tetrafluoroethylene, is equal to 1 6 to 1.2. The method according to p. 1, characterized in that the catalyst used industrial aluminum-palladium catalyst composition, wt.Palladium 1,8 2
3. The method according to p. 1, characterized in that as indifferent diluent used 1,1,2,2-Tetrafluoroethane.4. The method according to p. 1, wherein the process is conducted at a molar ratio of hydrogen and tetrafluoroethylene in the range of 0.9 to 1.2 1.5. The method according to PP. 2 and 4, characterized in that the process is conducted with the use of preheating of the catalyst by the filing of the original gaseous mixture, heated at least to the 50oC.
FIELD: industrial organic synthesis.
SUBSTANCE: invention is dealing with catalysts showing high catalytic stability in production of chloroform from carbon tetrachloride via catalytic dehydrochlorination reaction. Catalyst containing γ-alumina-supported platinum is characterized by that platinum in the form of particles 1 to 12 nm in size is distributed throughout the bulk of microspheric γ-alumina particles having median diameter 30 to 70 μm and pore volume 0.3 -0.6 cm3/g. Preparation of catalyst involves impregnation step accomplished via spraying γ-alumina with aqueous platinum compound solution used in amount equal to or less than alumina pore volume followed by platinum compound reduction step, wherein this compound is deposited onto γ-alumina with aqueous solution of formic acid or alkali metal formate.
EFFECT: achieved retention of high catalyst activity and selectivity over a long time period without being preliminarily activated.
9 cl, 2 tbl, 4 cl
FIELD: industrial organic synthesis.
SUBSTANCE: according to invention, carbon tetrachloride and an alkane are dissolved in chlorobenzene and then are added cupric chloride and complexion agent containing quaternary ammonium cation selected from selected from R4N+Cl- and (R1)3(R2)N+Cl-, wherein R represents hexyl, heptyl, or octyl, R1 butyl or octyl, and R2 is benzyl, at cation-to-copper molar ratio (10-5):1 and copper concentration 0.95-1.3 g/L to form anionic cupric chloride complex, which is used as catalyst in liquid-phase hydrogenation of carbon tetrachloride with isoalkane at 130-160°C for 2 to 11 h to form chloroform and isoalkane chlorinated in tertiary position.
EFFECT: enabled repetitive us of catalyst and increased selectivity of reaction.
1 tbl, 15 ex
SUBSTANCE: hydrogen donor used is methylene chloride, quaternary ammonium salts used are compounds of general formula R3R'NCl or R2R'2NCI, where R=C1-C18 - alkyl, R' - C1-C18 -alkyl, chloroalkyl or benzyl in molar ratio salt: copper equal to 8-10:1, concentration of copper is 0.1-0.5 g/l. The process is carried out at 180-200°C with molar ratio of carbon tetrachloride and methylene chloride equal to 1.5-6:1. The catalyst can be added in 2-4 portions after 90-120 minutes each.
EFFECT: selective method of producing chloroform without using scarce hydrogen donors.
2 cl, 2 tbl, 17 ex
SUBSTANCE: invention relates to methods of converting chlorohydrocarbons, specifically to methods for simultaneous production of chloroform and chloroparaffins. Described is a method for co-synthesis of chloroform and chloroalkanes from tetrachloromethane and alkane, which is carried out in liquid phase in the presence of a solid catalyst which is a product of reacting copper chloride, 3-chloropropyl trimethoxy-siloxane, tertiary amine or derivatives of imidazole and silica gel. The tertiary amine used is compounds of general formula R1R2R3N, where R is methyl, ethyl, propyl or isopropyl. The imidazole derivative is methyl- or ethyl-imidazole. Content of copper in the catalyst is equal to 1.5-2 wt %. The process for co-synthesis of chloroform and chloroalkanes is carried out at temperature 160-190°C and contact time of 3-5 hours in the presence of an organic additive selected from C2-C4 alcohols.
EFFECT: simplification of the process owing to exclusion of the step for purifying the end product from catalyst conversion products and resinous substances and possibility of using the catalyst many times.
2 tbl, 14 ex
SUBSTANCE: invention relates to a method of producing a fluorinated olefin product. The method involves the following: (a) bringing a stream of material containing reactants - fluorinated olefin and hydrogen - into contact with a first portion of a catalyst to convert said reactants to a hydrofluoroalkane with a first degree of conversion and obtain a first effluent containing said hydrofluoroalkane, unreacted fluorinated olefin and hydrogen; (b) bringing said first effluent into contact with a second portion of catalyst to convert said unreacted fluorinated olefin to a hydrofluoroalkane with a second degree of conversion, wherein the second portion of catalyst is bigger than the first and the second degree of conversion is higher than the first; (c) dehydrohalogenation of at least a portion of said hydrofluoroalkane from step (b) to form a stream of products containing fluorinated olefin and HF; and (d) optional separation of HF from said stream of products.
EFFECT: use of the present method improves overall degree of conversion and increases purity of the product.
15 cl, 10 ex, 7 tbl, 2 dwg
SUBSTANCE: invention relates to versions of a method of producing a fluorinated alkane. One of the versions comprises the following steps: (a) bringing at the first reaction step, a source stream containing fluorinated olefin and hydrogen into contact with a first amount of catalyst to obtain at least a first effluent stream containing fluorinated alkane, unreacted fluorinated olefin and hydrogen. The fluorinated olefin is fed to the first reaction step at a rate which is at least 60% higher than the throughput of the catalyst at the first reaction step, and results in the conversion of fluorinated olefin to fluorinated alkane which ranges from 10 to 60%. Then (b) at one or more additional reaction steps, bringing the effluent stream into contact with a second amount of catalyst to obtain fluorinated alkane, wherein the second amount is an amount for achieving conversion of the fluorinated olefin which is higher than the conversion of fluorinated olefin at the first reaction step (a), where the fluorinated olefin is a compound of formula (I): (CXnY3-n)(CR1 aR2 b)zCX=CHmX2-m (I) and the fluorinated alkane is a compound of formula (II): (CXnY3-n(CR1 aR2 b)zCHXCH2X (II), where: each X independently denotes Cl, F, I or Br; each Y independently denotes H, Cl, F, I or Br; each R1 independently denotes H, Cl, F, I or Br or an unsubstituted or halogen-substituted methyl or ethyl radical; each R2 independently denotes H, Cl, F, I, Br or an unsubstituted or halogen-substituted methyl or ethyl radical; n equals 1, 2 or 3; a and b are each equal to 1 of 2, provided that a+b=2; m equals 0, 1 or 2; and Z equals 0, 1, 2 or 3.
EFFECT: use of the present invention enables to simultaneously achieve high efficiency and selectivity.
14 cl, 2 ex, 2 dwg
SUBSTANCE: invention relates to versions of a method of producing 2,3,3,3-tetrafluoropropylene (1234yf), which includes: (a) reaction of 1,1,2,3,3,3-hexafluoropropylene (1216) with hydrogen in the presence of a hydrogenation catalyst to form 1,1,2,3,3,3-hexafluoropropane (236ea); (b) dehydrofluorination of 236ea to form 1,2,3,3,3-pentafluoropropylene (1225ye); (c) reaction of 1225ye with hydrogen in the presence of a hydrogenation catalyst to form 1,2,3,3,3-pentafluoropropane (245eb); and (d) dehydrofluorination of 245eb to form 1234yf. One of the versions of the method comprises continuously carrying out steps (a), (b), (c) and (d) in the given order and the second version comprises semi-continuously carrying out said steps using one hydrogenation reactor and one dehydrofluorination reactor.
EFFECT: use of the present method enables to avoid use of expensive reactants and formation of toxic by-products.
25 cl, 3 ex, 3 tbl, 3 dwg
SUBSTANCE: invention relates to a method of producing 2,3,3,3-tetrafluoropropylene (1234yf). The method includes: (a) reaction of 1,1,2,3,3,3-hexafluoropropylene (1216) with hydrogen in the presence of a hydrogenation catalyst to form 1,1,2,3,3,3-hexafluoropropane (236ea); (b) dehydrofluorination of 236ea to form 1,2,3,3,3-pentafluoropropylene (1225ye); (c) reaction of 1225ye with hydrogen in the presence of a hydrogenation catalyst to form 1,2,3,3,3-pentafluoropropane (245eb); and (d) dehydrofluorination of 245eb to form 1234yf, where steps (a) and (d) are carried out in the presence of a catalyst which contains activated carbon, a base metal and/or a transition metal.
EFFECT: use of the present method enables to avoid use of expensive reactants and formation of toxic by-products.
17 cl, 3 ex, 4 tbl, 3 dwg
SUBSTANCE: method includes crystallising perfluorodecalin in two steps: at the first step, crystallisation is carried out while reducing the temperature to minus 17°C - minus 18°C at a rate of 1-2°C per minute while stirring; the mass is held at a temperature of minus 17°C - minus 18°C for 30-35 minutes, filtered and dried and the obtained crystals are separated; the crystals are then melted at ambient temperature; at the second step crystallisation is repeated at the same conditions, but while reducing temperature to minus 15°C. The product obtained using the present method has purity higher than 99 wt %.
EFFECT: high purity of the finished product.