The method for preparing a titanium-silicate catalyst and method of liquid-phase oxidation of organic compounds

 

The invention relates to the field of synthesis of materials, which are used as catalysts for organic synthesis, and in particular to an improved method for producing a titanium-silicate catalyst for processes of selective oxidation of organic compounds by hydrogen peroxide. The invention solves the problem of developing a method of preparing mesoporous mesophase titanium-silicate materials, which will be simultaneously thermohydrodynamic and resistant to leaching of the active component (lichinga). This object is achieved in that the process of forming the titanium-silicate metastructuring materials is carried out in two stages. In the first phase, comprising preparing a mixture containing positively charged complexes of silicon, adding compounds of titanium and adding surface-active substances (SAS) (the order of mixing is arbitrary), the pH is maintained within the range of 0.5 to 1.5. The second phase will cover the introduction of a portion of the alkaline solution so that the pH of the reaction mixture was maintained in the range from 1.5 to 7.0, and then the mixture is subjected to hydrothermal treatment, after which the product is separated by filtration, washed, is ESA materials, which are used as catalysts for organic synthesis, and in particular to an improved method for producing a titanium-silicate catalyst for processes of selective oxidation of organic compounds by hydrogen peroxide.

Organic oxygen-containing compounds are valuable products and intermediates in organic synthesis. Until recently, the main way of their industrial production was stoichiometric, “polluting” the oxidation of such reagents as manganese dioxide, permanganate and bichromate of potash, nitric acid, etc. At the stoichiometric oxidation of use massive amounts of expensive and toxic, oxidizing agents, and inevitably there are problems associated with the disposal of toxic waste. In the last 10 years there has been a tendency to replace traditional stoichiometric catalytic methods that are much more acceptable from the point of view of ecology and economy. Of greatest interest catalytic methods for obtaining oxygen-containing compounds, based on the use as oxidant molecular oxygen and hydrogen peroxide, as both of these acyclical is a, in the small-capacity processes of fine organic synthesis using the first oxidizer is often preferable, because the cost of technological equipment for the oxidation of N2About2in General lower than for oxidation, which is usually carried out at elevated temperatures and pressures [R. A. Sheldon, J. Dakka. Heterogeneous catalytic oxidations in the manufacture of fine chemicals. Catalysis Today 19 (1994) 215].

Oxidation by molecular oxygen at “room temperature” is the most preferred, but still this process is not feasible. Therefore, it becomes increasingly popular to use a second “green” oxidant - N2O2that is called “ascending chemical star” and “the ideal oxidant”, because only formed from it by-product is water, and for the percentage of oxygen in the molecule H2About2stands in second place after molecular oxygen. To date, the best heterogeneous catalysts for liquid-phase oxidation of organic compounds by hydrogen peroxide are microporous titanium-silicalite TS-1 and TS-2 [EP 100119, B 01 J 29/04, 23.05.89; US 4410501, C 01 B 33/20, 1983; GB 2116974, C 07 C 37/60, 1983]. Process eye process produces about 10,000 tons per year of hydroquinone and pyrocatechin. The main drawback of TS-1 is the small diameter of the pores (0.56 nm), which makes it impossible for the conversion of large molecules. There are a number of attempts to create mesoporous molecular sieves (Ti-MCM-41, Ti-HMS, Ti-MMM and others), as well as amorphous mixed titanium-silicon oxides and their use in processes of selective oxidation of large molecules [US 5783167, C 01 B 33/20, 1998; US 5712402, C 07 C 50/02, 1998; US 5855864, C 01 B 033/26, 1999; US 5935895, B 01 J 23/00, 1999; RF Patent N 2164510, C 07 C 46/06, 2000].

Currently, the largest number of syntheses of silica and element-silicate mesostructured mesoporous materials (MCM-41, MMM and others) spend on reaction pathways for S+I-where the conditions for the electrostatic interaction of the cation surfactant (S+) and anionic forms of silicon dioxide (I-) [S. Biz, M. L. Occelli, Catal. Rev.-Sci. Eng, 40(3) (1998) 329; US 5783167, C 01 B 33/20, 1998]. The formation of these materials occurs in alkaline medium, with at least part of the oxygen atoms of the inorganic wall material has a negative charge that provides interaction with the cation surfactant. Unlike electroneutral SiOH groups, such charged atoms of oxygen are not able to form a siloxane bond Si-O-Si bonds by condensation during the hydrothermal oberspreewald to block the type of building system, the consequence of which is the low hydrolytic stability of the resulting materials [Century. N.Romannikov, S. D. Kirik, L. A. Solovyov, A. N. Shmakov, A. Y. Derevyankin, C. B. Fenelonov, N. N. Leaders, O. A. Kholdeeva, O. B. Lapina, E. A. Paukshtis. Physico-chemical properties of mesoporous mesophase silicate materials, formed by the mechanism of S+I-. Kinetics and catalysis, 2001, T. 42, N6, S. 1-10]. In turn a consequence of the low hydrolytic stability is the destruction of the structure of the catalyst during the process of liquid-phase oxidation using aqueous hydrogen peroxide, resulting in loss of catalyst activity during its repeated use [L. Y. Chen, G. K. Chuah, and S. Jaenicke. Ti-containing MCM-41 catalysts for liquid phase oxidaton of cyclohexene with aqueous H2O2and tert-butyl hydroperoxide. Catal. Lett. 50 (1998) 107; O. A. Kholdeeva, N. N. Trukhan, M. P. Vanina, V. N. Romannikov, V. N. Parmon,A New Environmentally Friendly Method for the Production of 2,3,5-trimethyl-p-benzoquinone. Catalysis Today, 2002, v.75, N 1-4, p.203]. There are attempts for more stabilization of the structure of materials such as MCM-41 using various chemical techniques, in particular by the additive synthesis of water-soluble organic and inorganic salts, but this leads to the loss of the mesostructure and education rauparaha when pH values, close to 7 [US 5855864, C 01 B 033/26, 1999], which in this case is implemented on the reaction path S0I0through van der Vaal's interaction electrically neutral uncharged surfactants and silica particles. However, as stated by [P. T. Tanev and T. J. Pinnavaia, Mesoporous silica molecular sieves prepared by ionic and neutral surfactant templating: A comparison of physical properties. Chem. Mater., 8 (1996) 2068], the level of structural organization of these materials is very low and, therefore, effective management of the catalytic properties of such systems is difficult.

Known to the formation of silicate mesostructures materials in strongly acidic media at pH values, typically between 1 and less than [WO 9937705, C 08 J 9/00, 1999; P. T. Tanev and T. J. Pinnavaia. Chem. Mater., 8 (1996) 2068], which can be implemented on the reaction path S+X-I+, i.e., by electrostatic interaction of the cation surfactant (S+and electrically neutral particles of silicon dioxide with a partially protonated surface silanol groups (schematically the I+=N2O+Si(OH)3), mediated through the added anions (usually X-=CL-). In this case, the level of organization of the mesostructure and, consequently, the degree of controllability of its properties is stabilnosti of such materials is very high [Y. H. Yue, A. Gedeon, J.-L. Bonardet, N. Melosh, J.-B. D Espinose, J. Fraissard. Direct synthesis of A1SBA mesoporous molecular sieves: characterization and catalytic activities. J. Chem. Soc. Chem. Commun., (1999) 1967], as particles of silicon dioxide involved in the formation of mesostructure not contain hard-ionized atoms of oxygen, preventing the full polycondensation in silicate wall.

Thus, it is the latter described the reaction of the ways seems to be the most promising for the formation metastructuring catalytic systems on the basis of item-silicates. However, the strongly acidic environment give rise to problems associated with the fact that the introduction of heteroelement in such systems [Y. Yue, A. Gedeon, J.-L. Bonardet, N. Melosh, J.-B. D Espinose, J. Fraissard. Direct synthesis of mesoporous AlSBA molecular sieves: characterization and catalytic activities. J. Chem.Soc. Chem. Commun., (1999) 1967], the latter is practically not recorded in the silicate wall and is easily washed away during liquid-phase reactions (so-called leaching active component). Synthesis in alkaline medium according to the mechanism of S+I-conversely , allows to obtain a material resistant to lichinga in terms of liquid-phase oxidation by hydrogen peroxide [RF Patent N 2164510, C 07 C 46/06, 2000; N. N. Trukhan, V. N. Romannikov, E. A. Paukshtis, A. N. Shmakov, O. A. Kholdeeva. Oxidation of 2,3,6-trimethylphenol o is ucture silicate walls of these materials is destroyed in the presence of water.

Closest to the present invention is a method for mesoporous silicate materials, including the preparation of an aqueous solution of sodium silicate at pH>9, mixing this solution with an acidic aqueous solution of nonionic surface-active substances (SAS) - based amphiphilic block copolymer polyoxyethylenated (REO) so that the pH of the mixture is in the range from 4 to 10, aging the mixture at a temperature of from 0 to 150°C, adding heteroelement and the continuation of the aging process, removing the solvent and subsequent removal of the surfactant extraction and/or annealing [US Patent Appl. 20010043901, 01 033/32, 2001].

Obtained in this method, materials are disordered structure of mesopores with a similar size with a diameter of from 1.5 to 30 nm, the thickness of the walls between adjacent pores >0.5 nm, specific surface 300-1400 m2/g, pore volume of 0.2-3.0 cm3/g and possess thermal stability, however, about their hydrostability [US Patent Appl. 20010043901, 01 033/32, 2001] is not reported. According to the literature views the formation of a water resistant silicate walls of the mesoporous material can be performed only in highly acidic environment.

The invention solves shadowdemon thermohydrodynamic and resistant to leaching of the active component (lichinga).

The development of such materials is first in a series of strategic tasks of fine organic synthesis, based on the use of aqueous hydrogen peroxide [W. R. Sanderson. Cleaner Industrial Processes using Hydrogen Peroxide. Pure and Appl. Chem. 72 (2000) 1289; I. W. C. E. Arends, R. A. Sheldon. Activities and stabilities of heterogeneous catalysts in selective liquid phase oxidations: recent developments. Appl. Catal. A: General. 212 (2001) 175].

This object is achieved in that the process of forming the titanium-silicate metastructuring materials Ti-MMM-2 is carried out in two stages. At the first stage of preparing a mixture containing positively charged complexes of silicon, a compound of titanium and surface-active substances (SAS), the pH is maintained within the range of 0.5 to 1.5. In the second stage, introducing a portion of the alkaline solution so that the pH of the reaction mixture was maintained in the range from 1.5 to 7.0. After that, the mixture is subjected to hydrothermal treatment, then the product is separated by filtration, washed, dried and calcined.

As compounds of titanium using a solution of salts of titanium (III) or (IV) in aqueous mineral acid or a solution of titanium alkoxides in an organic or aqueous-organic solvent or mixtures thereof. As acid using Hcl, NVG, N2SO4, lO4, HNO1-C12, ketones, carboxylic acids, acetonitrile.

Part of the titanium ion in an amount of from 1 to 99 wt.% can be replaced by heteroelement selected from a number of: Al, In, Ga, Fe; Cr, Zr, Sn, Ge.

As surface-active substances are used, alkyltrimethylammonium halides or hydroxides of the General formula CnH2n+1(CH3)3NX, where n=12-18; X=CL, Br, IT, oligomeric alkylpolyglucoside General formula CnH2n+1+EOmwhere n=12-18; m=2-25, and oligomeric alkylpolyglucoside, polyoxy(accelerated) block copolymers or mixtures thereof.

The molar ratio of silicon to titanium take in the range of 10-150. The molar ratio of silica to surfactant charge in the range of 0.2-100.

The hydrothermal treatment is carried out at a temperature of 20-150°C for 0.2-120 hours.

The task is also solved by way of the process of liquid-phase selective oxidation of organic compounds by hydrogen peroxide in the presence of mesoporous titanium-silicate catalyst, prepared as described above.

Using the proposed method allows you to get organized mesoporous mesophase titanium silicate catalysts. In Fig.1 shows electron microscopic optimum surface 1147 m2/g and the volume of mesopores 0.74 cm3/, No variation in the diameter between the various mesopores is confirmed by the fact that the area(R/Rabout), within which the capillary condensation of nitrogen at 77 K, is very narrow. In Fig.2 shows the adsorption isotherm for Ti-MMM-2. Ti-MMM-2 retain the structural and textural characteristics boiling in water for several hours. This is confirmed by the data of x-ray analysis, is shown in Fig.3 (curve 1 was obtained for the original sample, Ti-MMM-2 (2 wt.% Ti), curve 2 is obtained for the same sample after boiling in water for 6 h and subsequent annealing at 600°C). Ti-MMM-2 retains a high specific surface area when the cyclic processing in the water (boiling, drying). Relevant data on low-temperature adsorption of N2presented in Table 1. State of titanium in Ti-MMM-2 close to a stand-alone, as evidenced by the position of the maximum (about 210 nm) in the UV spectrum of diffuse reflection (Fig.4). These materials possess high activity in the oxidation reactions of organic substrates in water by hydrogen peroxide. During liquid-phase oxidation reaction of aqueous hydrogen peroxide kepolisian many times without loss of activity. The catalytic properties of the obtained materials, primarily selectivity can be varied by replacing a part of the titanium ion to other heteroelement (M, Y), for example, M=Al, In, Ga, Fe, Cr; Y=Zr, Sn, Ge, etc.

The invention is illustrated by the following examples.

Example 1. In the Sol of silicic acid (at a ratio of Si:H2O, equal to 25, pH~1.1) add a solution of titanium sulfate (ratio of Ti:Si=0.022). To the resulting solution was added surfactant - (SAS: Si=1:0.78 mol)16H33N(CH3)3VG (Lancaster) with thorough stirring and slight heating. The mixture was incubated at room temperature for from 12 to 48 h, the pH of the mixture of 0.9-1.0, and then add sodium silicate with vigorous stirring, while the molar ratio of Si/Ti is 39. the pH of the solution was adjusted to a value of 2.5, and the final product is subjected to hydrothermal treatment at 50°C for 15 min, then filtered, washed, dried and calcined at 600°C for 6 hours, the Obtained sample Ti-MMM-2 is a mesoporous mesophase titanium-silicate with hexagonal packing of uniform mesopores with a diameter of d=2.5 nm and the thickness of the silica wall h=1.0 nm. The content of Ti 2.0 wt.%, state titanium close to isolated (estimated from adsorption data are 1147 m2/g and 0.74 cm3/g respectively. After boiling in water for 6 h, the structure of the material is preserved (Fig.3, table 1).

Example 2. Synthesis is carried out as in example 1, but take molar ratio Si/Ti equal to 19, resulting in a receive sample Ti-MMM-2, containing 4.0 wt.% Ti (max=220 nm). The surface area of mesopores S=1131 m2/g, the volume of mesopores=0.69 cm3/g, the diameter of the mesopores d=2.5 nm.

Example 3. Synthesis is carried out as in example 1, but take molar ratio Si/Ti equal to 9, resulting in a receive sample Ti-MMM-2, containing 8.0 wt.% Ti (max=223 nm). The surface area of mesopores S=933 m2/g, the volume of mesopores=0.65 cm3/g, the diameter of the mesopores d=2.3 nm.

Example 4. Synthesis is carried out as in example 1 but conducting the aging of silica Sol at a temperature of 40°C for 4 h and then at room temperature for 20 h, resulting in a receive sample Ti-MMM-2, containing 2.0 wt.% Ti (max=214 nm). The surface area of mesopores S=1119 m2/g, the volume of mesopores=0.71 cm3/g, the diameter of the mesopores d=2.6 nm.

Example 5. sub>12H25N(CH3)3VG, resulting in receiving a sample of Ti-MMM-2, containing 2.0 wt.% Ti (max=225 nm). The surface area of mesopores S=671 m2/g, the volume of mesopores=0.3 cm3/g, the diameter of the mesopores d=2.0 nm.

Example 6. Synthesis is carried out as in example 1, but instead of 0.018 mol16H33N(CH3)3VG add 0.018 mol alkylpolyglucoside Brij 56 General formula C16H33SW10resulting in getting a sample containing 2.0 wt.% Ti (max=226 nm). The surface area of mesopores S=1072 m2/g, the volume of mesopores=0.66 cm3/g, the diameter of the mesopores d=2.7 nm.

Example 7. Synthesis is carried out as in example 1, but instead of Ti(SO4)2use a solution of Tetra-isopropoxide titanium in ethyl alcohol, modified equimolar amounts of H2SO4in the result, get a sample of Ti-MMM-2, containing 1.8 wt.% Ti (max=243 nm). The surface area of mesopores S=980 m2/g, the volume of mesopores=0.58 cm3/g, the diameter of the mesopores d=2.9 nm.

Example 8. Synthesis is carried out as in example 1, but the hydrothermal treatment is carried out at 30°C for 18 h, poverhnosti mesopores S=1165 m2/g, the volume of mesopores=0.73 cm3/g, the diameter of the mesopores d=2.4 nm.

Example 9. Synthesis is carried out as in example 1, but hydrothermal treatment at 100°C for 0.5 h, the resulting get a sample of Ti-MMM-2, containing 2 wt.% Ti (max=258 nm). The surface area of mesopores S=879 m2/g, the volume of mesopores=0.55 cm3/g, the diameter of the mesopores d=3.1 nm.

Example 10. Synthesis is carried out as in example 1, but an additional portion of sodium silicate is injected in an amount such that the pH of the mixture subjected to hydrothermal treatment was equal to 3.0, resulting in a receive sample Ti-MMM-2, containing 2.2 wt.% Ti (max=243 nm). The surface area of mesopores S=1009 m2/g, the volume of mesopores=0.68 cm3/g, the diameter of the mesopores d=2.6 nm.

Example 11. Synthesis is carried out as in example 1, but followed by a solution of TiOSO4enter the same number of equimolar solution of Al(SO4)3in the result, get a sample of Ti-MMM-2, containing 2.0 wt.% Ti (max=212 nm) and 1.9 wt.% A1. The surface area of mesopores S=11012/g, the volume of mesopores=0.73 cm3/g, the diameter of the mesopores d=2.8 nm.

Prima is about get a sample of Ti-MMM-2, containing 2.0 wt.% Ti (max=211 nm). The surface area of mesopores S=1135 m2/g, the volume of mesopores=0.72 cm3/g, the diameter of the mesopores d=2.7 nm.

Example 13. Synthesis is carried out as in example 1, but additionally in the reaction mixture is injected solution of aluminium sulphate in the ratio of Al:Ti equal to 1.0, resulting in receiving a sample containing 2.0 wt.% Ti and 2.0 wt.% Al (max=212 nm). The surface area of mesopores S=1077 m2/g, the volume of mesopores=0.74 cm3/g, the diameter of the mesopores d=2.6 nm.

Example 14. Synthesis is carried out as in example 1, but additionally in the reaction mixture is introduced a solution of sulphate of iron in a ratio of Fe:Ti equal to 1.0, resulting in receiving a sample containing 2.0 wt.% Ti and 2.0 wt.% Fe. The surface area of mesopores S=1213 m2/g, the volume of mesopores=0.87 cm3/g, the diameter of the mesopores d=2.4 nm.

Examples 15-19 show the possibility of application of the obtained mesoporous titanium-silicate materials as catalysts in the processes of selective oxidation of organic compounds water-peroxide oxygen.

Example 15. In thermostatted at 80°C glass reactor, equipped with magnetic is With catalyst, the synthesis of which is described in Example 1, and 3 ml of acetonitrile. Then added with stirring to 140l (1.05 mmol) of 28% N2About2. The mixture is intensively stirred at 80°C. After 0.3 h conversion of TMP and output 2.3,5-trimethyl-1.4-benzoquinone (TMBG) per unreacted TMP defined by GLC, are 99 and 82%, respectively. The catalyst is filtered off, washed with methanol, air-dried and used again. After 0.5 h, the conversion of TMP and output TMBH be 100 and 81%, respectively.

Example 16. The process is carried out as in example 13, but using instead of 2,3,6-TMP 2.6-ditertbutyl. After 2.5 h, the conversion of initial phenol 53%, the yield of 2,6-ditretbutilfenol 80%.

Example 17. The process is carried out as in example 13, but after 4 min after start of the reaction the catalyst is filtered off and watching the transformation of TMP in the filtrate by GLC. In Fig.5 shows the kinetic curves of the oxidation of TMP H2O; in the presence of Ti-MMM-2 catalyst: curve 1 - without filtering, curve 2 - the catalyst removed after 4 min after start of the reaction. This example shows that the oxidation of TMP is a heterogeneous process and occurs in the matrix of the catalyst, not in the bulk solution due to the leaching of titanium.

l methylphenylsulfonyl (ISF) (0.30 mmol), 14 mg calcined at 600°C catalyst, the synthesis of which is described in example 1 (the content of Ti in the catalyst - 2.0 wt.%) and 3 ml of acetonitrile. Then added with stirring 46l (0.39 mmol) of 28% H2O2. The mixture is intensively stirred at 20°C. After 35 min, the conversion of the ISF and the output of methylphenylsulfonyl (IFRS), determined by GLC add up to 100% and 78%, respectively. After the reaction the catalyst is filtered off, washed with methanol, air-dried at room temperature and used again. Reuse of the catalyst does not lose its activity and selectivity (table 2).

Example 19. In thermostatted at 50°C glass reactor, equipped with a magnetic stirrer and a condenser, are placed 69l (-)-caryophyllene (0.30 mmol), 14 mg calcined at 600°C catalyst, the synthesis of which is described in example 1 (the content of Ti in the catalyst 2.0 wt.%) and 3 ml of acetonitrile. Then added with stirring 39l (0.33 mmol) of 28% H2O2. The mixture is intensively stirred at 50°C. After 4 h, the conversion of caryophyllene and output 4.5-monoepoxide defined by GLC, $ 75 and osobu mesoporous mesophase titanium silicate catalysts are simultaneously thermohydrodynamic and resistant to leaching of the active component (lichinga).

The resulting catalysts have high activity for oxidation reactions of organic substrates in water by hydrogen peroxide. During liquid-phase oxidation reaction of aqueous hydrogen peroxide heteroelement not washed out from the silicate matrix, the catalyst was separated by simple filtration and can be reused without loss of activity.

Claims

1. The method for preparing a titanium-silicate catalyst from a mixture containing positively charged complexes of silicon, a compound of titanium and a surfactant, characterized in that it is carried out in two stages, where in the first stage, preparing a mixture containing positively charged complexes of silicon, a compound of titanium and a solution of surfactant at pH 0.5 to 1.5, in the second stage to increase the pH of the reaction mixture is from 1.5 to 7.0, and then carry out the hydrothermal treatment.

2. The method according to p. 1, characterized in that the connection use titanium salt solution of titanium (III) or (IV) in aqueous mineral acid or a solution of titanium alkoxides in an organic or aqueous-organic solvent.

3. The method according to PP.1 and 2, characterized in that as cyclicality fact, as the organic solvent used miscible with water, alcohols C1-C12, ketones, carboxylic acids, acetonitrile.

5. The method according to any of paragraphs.1-4, characterized in that the portion of the titanium ion in the amount of 1-99 wt.% replace heteroelement selected from a number of: Al, In, Ga, Fe, Cr, Zr, Sn, Ge.

6. The method according to any of paragraphs.1-5, characterized in that as surface-active substances are used, alkyltrimethylammonium, halides or hydroxides of the General formula CnH2n+1(CH3)3NX, where n=12-18; X=CL, Br, IT, oligomeric alkylpolyglucoside General formula CnH2n+1EOmwhere n=12-18; m=2-25, and polyoxy(accelerated) block copolymers (REOnPPOmREOpwhere 0<n<100, 5<m<150, 0R<100), or any mixture.

7. The method according to any of paragraphs.1-6, characterized in that the molar ratio of silicon:titanium 10-150.

8. The method according to any of paragraphs.1-7, characterized in that the molar ratio of silicon:surface-active agent is 0.2-100.

9. The method according to any of paragraphs.1-8, characterized in that the hydrothermal treatment is carried out at a temperature of 20-150°C for 0.2 to 120 hours

10. The method according to any of paragraphs.1-9, characterized in that after hydrothermalis liquid-phase selective oxidation of organic compounds in the presence of mesoporous titanium-silicate catalyst and hydrogen peroxide, characterized in that the process is carried out in the presence of a catalyst obtained according to any one of paragraphs.1-10.

 

Same patents:

The invention relates to the field of synthesis of biologically active substances, in particular to the synthesis of isoprenoid derivatives 2,3,5-trimethyl-1,4-benzoquinone, which receive the acid-catalyzed condensation reaction of trimethylhydroquinone with allylic isoprenoid alcohols, using as a catalyst the zeolite aluminosilicate CSK-5"

The invention relates to the production of alkyl substituted quinones by oxidation of alkylaromatic compounds by hydrogen peroxide, in the presence of porous amorphous titanium silicate catalyst - aerogel or xerogel, with a titanium content of not less than 0.2 wt.%

The invention relates to organic synthesis, namely the method of production of 2,3,6-trimethylbenzoquinone (TMBG), which is an intermediate in the synthesis of vitamin E, which is widely used in clinical practice and animal husbandry

The invention relates to organic chemistry and can be used in the synthesis of 4-alkyl-ortho-benzoquinoines and 3-bromo-5-alkyl-ortho-benzoquinoines

The invention relates to a method for producing aromatic carboxylic acids by exothermic liquid-phase oxidation reaction of the corresponding alkylaromatic parent compound in the liquid-phase reaction mixture consisting of water, low molecular weight monocarboxylic acid as a solvent, the oxidation catalyst on the basis of heavy metal and a source of molecular oxygen in the reaction conditions leading to the gaseous exhaust stream of high pressure water-containing gaseous by-products and gaseous low molecular weight monocarboxylic acid, followed by distillation of the aromatic carboxylic acid and separation of the exhaust flow high pressure, while the exhaust flow high-pressure direct high-performance distillation column to remove at least 95 wt.% low molecular weight monocarboxylic acid from the waste stream, with the formation of the second exhaust flow high-pressure containing water and gaseous by-products formed in the oxidation process, and then the second exhaust stream of high pressure is directed to the means for the release of energy from the second exhaust flow
The invention relates to catalysts for the oxidation of organic compounds and oligomerization of the olefin-based crystalline zeolite material type, namely on the basis of such silicalite and to a method for producing such a catalyst
The invention relates to a technology for production of liquid glass
The invention relates to a technology for production of liquid glass with different silicate module used in soap, fatty, chemical, machine-building, textile and paper industries, as well as in the construction industry, metallurgy and for other purposes
The invention relates to the production of alkali silicates and may find application in the chemical industry in the manufacture of detergents, cleaning, bleaching, disinfectants, textile, metallurgy, machine building, oil refining and other industries

The invention relates to silicate industry, in particular to methods of production of liquid glass, and can be used in the manufacture of welding electrodes, t

The invention relates to the manufacture of cementitious compositions, namely the manufacture of translucent binder compositions used in the manufacture of fire retardant translucent glass (OSS)

The invention relates to a method for producing aqueous solutions of silicates and can be used in the welding industry as a binder in the manufacture of electrodes

The invention relates to construction materials and can be used in the production of liquid glass for heat-resistant, acid-resistant concrete, in the manufacture of paints and other areas

The invention relates to the production of liquid glass

The invention relates to methods for producing liquid glass

The invention relates to a technology for production of liquid glass and can be used to produce acid-resistant and heat-resistant materials, to obtain a binder for particleboard, etc

The invention relates to the production of liquid catalysts on the basis of aromatic sulfonic acids for the hydrolysis of fats

The invention relates to catalysts for obtaining hydrocarbons, including liquid synthetic fuels, olefins, solid hydrocarbons and their oxygenated derivatives, such as alcohols from a mixture of CO and hydrogen
Up!