Two oxygen atoms, e.g. succinic anhydride (C07D307/60)

C   Chemistry; metallurgy(318790)
C07   Organic chemistry(61593)
C07D307/60                     Two oxygen atoms, e.g. succinic anhydride(49)

ethod and intermediate compounds for pregabaline production // 2628298
FIELD: pharmacology.SUBSTANCE: invention relates to a method for preparation of a compound of the formula and intermediates used to implement the method, as well as a method for pregabalin preparation.EFFECT: method can be implemented on a commercial scale using readily available, safe raw materials and reagents, and without the need for difficult separations.20 cl, 8 tbl, 41 ex

Improved solvent for extraction of maleic anhydride from gas stream // 2607762
FIELD: chemistry.SUBSTANCE: invention relates to methods of producing raw maleic anhydride. In particular, method includes steps where: reactor output stream, containing maleic anhydride, is fed into bottom part of absorption column, where it comes into contact with a non-cyclic solvent, that is fed close to its upper part and is a diester, having a boiling point under normal conditions between 250C and 350C, solubility of fumaric acid at least 0.06 wt% at temperature of 60C, solubility of maleic anhydride at least 10 wt% at temperature of 60C, water solubility not higher than 100 mg/l, density, different from water density at least to 0.020 g/ml, and a water-soluble hydrolysis product with molecular weight not higher than that of pentanol, with transfer of maleic anhydride of outlet stream of reactor into a solvent, wherein gas stream to be extracted is blown off from absorption column, and enriched solvent, containing maleic anhydride, is removed from absorption column near bottom of absorber and directed into flash tower near its middle part, untreated maleic anhydride is removed from stripping column near its middle or upper part.EFFECT: methods make it possible to use cheaper solvent than phthalates.11 cl, 1 dwg, 1 tbl
Shell-and-tube reactor for producing maleic acid anhydride // 2566749
FIELD: chemistry.SUBSTANCE: invention relates to an apparatus for producing maleic acid anhydride via heterogeneous catalytic gas-phase oxidation of an initials stream containing hydrocarbons with at least 4 carbon atoms per molecule, which includes a reactor with a bundle of reaction tubes in which there is a solid-phase catalyst on which an exothermic reaction of the initial stream and an oxygen-containing stream occurs, one or more pumps and one or more heat exchangers mounted outside the reactor, through which a heat carrier flows, which is a molten salt which follows through the space between the reaction tubes, thereby receiving the reaction heat, wherein temperature of the molten salt lies in the range between 350 and 480C. The reaction tubes are made of heat-resistant alloy steel containing at least 0.25 wt % molybdenum, or at least 0.5 wt % chromium and at least 0.25 wt % molybdenum.EFFECT: apparatus is characterised by high stability.5 cl, 4 ex

ethod of separation of fumaric acid and other side components in obtaining maleic acid anhydride // 2505537
FIELD: chemistry.SUBSTANCE: method is realised by heterogeneous catalytic oxidation of carbon by molecular oxygen, selected from group of benzol, n-butane, n-butene, in presence of catalyst, which contains vanadium, phosphorus and oxygen, which includes: (a) maleic acid anhydride absorption from impure mixture of products by absorbing agent, which contains organic solvent, in absorption column; (b) desorption of maleic acid anhydride from absorbing agent, which is obtained at stage (a), enriched by maleic acid anhydride, in desorption column; as well as (c) total or partial return to stage (a) of absorbing agent, depleted at stage (b) by content of maelic acid anhydride, is differ in fact, that (d) total or partial quantity of absorbing agent, depleted on stage (b) by content of maelic acid anhydride, for required sedimentation of fumaric acid is cooled and/or subjected to concentration by evaporating absorbing agent to such degree, that difference between concentration of fumaric acid in reverse flow at output from desorption column c (FA, at output from desorption column) at there existing conditions, expressed in weight p/mln, and balanced concentration of fumaric acid, corresponding to solubility curve, after cooling and/or evaporation of absorbing agent part c (FA, balanced, after cooling/steaming), expressed in weight p/mln, constitutes value larger or equal 250 wt, p/mln, and for sedimentation and separation of fumaric acid applied is reservoir with built-in nozzle elements, and average time of staying in reservoir with built-in nozzle elements constitues from 0.05 to 6 hours; (e) fumaric acid, precipitated in form of solid substance due to operations at stage (d), totally or partially, in continuous or periodic mode is removed from reverse flow of absorbing agent; and (f) depleted by content of fumaric acid absorbing agent from stage (e) totally or partially returns on stage (a).EFFECT: reduction of formation of fumaric acid sedimentations with obtaining maelic acid anhydride.12 cl, 3 dwg, 5 ex

Paper sizing additive, methods of producing and using said additives // 2487870
FIELD: chemistry.SUBSTANCE: present invention relates to a method of producing an alkenyl-substituted cyclic anhydride, comprising the following steps: isomerising one or more olefinically unsaturated C6-C28 hydrocarbons, from which at least 30 wt % is alpha-olefin, by contacting said hydrocarbons with a catalyst which contains an alkali metal on a support, and reacting the formed isomerised C6-C28 olefin hydrocarbons with a cyclic anhydride of an unsaturated dicarboxylic acid to form an alkenyl-substituted cyclic anhydride.EFFECT: invention relates to use of said compound as a paper sizing additive and a method of producing said additive based on the obtained alkenyl-substituted cyclic anhydride.20 cl, 2 tbl, 4 ex

ethod of producing ketopantolactone // 2461554
FIELD: chemistry.SUBSTANCE: present invention relates to a method of producing ketopantolactone, which is widely used in synthesis of pantothenic acid (vitamin B5), as well as other biologically active substances. The method of producing ketopantolactone involves oxidative dehydrogenation of pantolactone under the action of electrochemically generated bromine from a bromide anion source in an electrolysis cell equipped with an anode, a cathode and a stir-bar in the medium of a chlorine-containing organic solvent in a two-phase system containing an organic and an aqueous layer while passing electrical current of 4-6 F per 1 mole pantolactone and stirring the reaction mass at a rate of 1-4 rps at temperature 35-70C and pH of the medium equal to 0.5-1.5.EFFECT: simple technology of producing ketopantolactone, avoiding the need to use dangerous (poisonous) and hard to handle molecular bromine, high conversion of the starting pantolactone and high output of the end product which reaches 85%.4 cl, 12 ex, 1 tbl, 1 dwg
ethod of preventing precipitation of fumaric acid when producing maleic acid anhydride // 2458057
FIELD: chemistry.SUBSTANCE: invention relates to an improved method of preventing precipitation of fumaric acid when producing maleic acid anhydride comprising the following steps: a) absorption of maleic acid anhydride from the mixture of products obtained as a result of partial oxidation of benzene, olefins having 4 carbon atoms and n-butane, in an organic solvent or water as an absorbent, b) separation of maleic acid anhydride from the absorbent, containing fumaric acid, wherein the absorbent regenerated thus, which contains fumaric acid, is completely or partially catalytically hydrogenated and completely or partially returned to the absorption step (a), wherein fumaric acid is hydrogenated to amber acid.EFFECT: method enables to prevent precipitation on equipment components and the resulting clogging, cleaning procedures and switching off.16 cl, 8 ex
ethod of producing maleic anhydride and catalyst used therein (versions) // 2421452
FIELD: chemistry.SUBSTANCE: invention relates to a method of producing maleic anhydride in a fluidised bed by oxidising material which contains C4 hydrocarbons with molecular oxygen or oxygen-containing gas in a reactor with a fluidised bed at reactor temperature 325-500C in the presence of a catalyst capable of working in the fluidised bed, containing mixed oxides of vanadium and phosphorus, wherein the catalyst is prepared as follows: (a) preparation of a catalyst precursor containing mixed vanadium and phosphorus oxide; (b) packing the catalyst precursor; (c) crushing the catalyst precursor to particles whose average size is less than one micrometre in diametre; (d) moulding particles which are capable of working in the fluidised bed, with bulk density greater than or equal to 0.75 g/cm3 from the packed crushed catalyst precursor; and (e) annealing said particles in boiling conditions, where output of the maleic anhydride is increased by adding a compensating catalyst into the reactor with the fluidised bed, wherein said compensating catalyst contains alkyl ether of orthophosphoric acid of formula (RO)3P=O, where R is hydrogen or C1-C4 alkyl and at least one R is C1-C4 alkyl, where the compensating catalyst is prepared by saturating the catalyst obtained according to steps (a) to (e) with alkyl ether of orthophosphoric aid. The invention also discloses a method of improving operation of the mixed vanadium-phosphorus oxide catalyst for producing maleic anhydride from butane in a fluidised bed. The invention also relates to a catalyst capable of working in the fluidised bed, for producing maleic acid by oxidising material which contains C4 hydrocarbons.EFFECT: invention ensures high output of the end product at low working temperatures.31 cl, 2 tbl, 2 ex
aleic anhydride purification method // 2399618
FIELD: chemistry.SUBSTANCE: method of purifying maleic anhydride involves heating molten initial crude product to 60-65C and then cooling to 53-54C and filtering at temperature of 51.5-53C. Filtration is carried out on a filter with hole size of 0.01-0.05 mm and the molten mass is thermally processed in an atmosphere of dry inert gas or in sealed conditions in an atmosphere of dry inert gas.EFFECT: high technological effectiveness of the process owing to its short duration and use of lower temperature parametres and higher degree of purification of maleic anhydride.1 cl, 1 ex

2,4,6-phenyl-substituted cyclic ketoenols // 2353615
FIELD: chemistry.SUBSTANCE: described are 2,4,6-phenyl-substituted cyclic ketoenols of formula (I, in which W, X, Y and CKE are given in invention formula. Also described are esters of acylamino acids of formula (II), substituted derivatives of phenylacetic acid of formula (XXIX), (XXVII), (XXXI), which are intermediate compounds for obtaining formula (I) compound.EFFECT: obtaining herbicidal preparation containing combinations of biologically active substances, including (a), formula (I) compound and (b') improving compatibility with cultural plants mefenpyr-diethyl, with weight ratio 5-1:1-7.7.9 cl, 46 tbl, 36 ex

System of automatic temperature profile support in reactor // 2326424
FIELD: physics; operation.SUBSTANCE: invention relates to the chemical industry, particularly to the automatic control systems and can be used for temperature support of the reaction mixture in chemical reactors. The system of automatic temperature profile support in the reactor with distributed constants in maleic anhydride production contains two control systems: cascade automatic control system (ACS) of coolant temperature control in the reactor and ACS of benzene-air mixture fed to the reactor where the correction signal is inleted according to reaction mixture temperature. The correction signal represents the sum of the signals about reaction mixture temperature in the measurement points positioned along the reactor height multiplied to the weight factor determined intuitively or from optimization problem solution. Then the correction signal is compared with assignment signal on the functional generator serving as algebraic adder. The invention allows to increase the temperature support accuracy in the reactor at maleic anhydride production.EFFECT: increasing of the temperature support accuracy in the reactor.2 cl, 2 dwg

The method of obtaining cyclic anhydrides or aliphatic nitriles, the method of obtaining maleic anhydride and a method of producing acrylonitrile and methacrylonitrile // 2058978
The invention relates to a method for producing a cyclic anhydride or a nitride of hydrocarbon and oxygen-containing gas in the presence of an appropriate catalyst, in particular to a method of reducing or eliminating the risk of explosion or fire in the headspace of the reactor system, in which there is a formation of the anhydride, or nitrile of hydrocarbon and oxygen

The way to produce succinic anhydride // 2058311
The invention relates to a method for obtaining succinic anhydride used in the production of pharmaceuticals, insecticides, as a hardener of epoxy resins, in analytical chemistry

The method of obtaining tarakanova anhydride // 2058296
The invention relates to organic synthesis

The way to produce succinic anhydride // 2044731
The invention relates to a method for producing succinic anhydride, which can find application in the chemical industry

The method of obtaining anhydride, endo-norbornene-2,3-dicarboxylic acid // 2032682
The invention relates to anhydrides of dibasic acids, in particular to an improved method for producing anhydride, endo-norbornene-2,3-dicarboxylic acid, which is used for the synthesis of unsaturated polyesters, alkyd resins