Abstract:
The invention relates to a method for producing optionally akyl-substituted 1,4-butandiol by two-stage catalytic hydration in the gaseous phase of C4 dicarboxylic acids and/or the derivatives thereof with the steps of: a) introducing a gaseous flow of a C4 dicarboxylic acid or a derivative thereof at 200 to 300 °C and 2 to 60 bar in a first reactor and catalytic gas phase hydration to a mainly optionally alkyl-substituted gamma-butyrolactone containing product; b) introducing the product flow so obtained into a second reactor at a temperature of from 150 °C to 240 °C and a pressure of from 15 to 100 bar and catalytic gas phase hydration to optionally alkyl-substituted 1,4-butandiol; c) removing the desired product from the intermediates, byproducts and possibly not reacted educt; d) optionally returning non-reacted intermediates to one or both hydration stages, whereby in both hydration stages one catalyst each is used which comprises = 5 % by weight, preferably 5 to 95 % by weight, especially 20 to 90 % by weight of an oxidic carrier, the pressure prevailing in the second reactor is higher than in the first reactor, and the product mixture removed from the first reactor is introduced into the second reactor without further purifying it.
Abstract:
The invention relates to a catalyst containing from 0.1 to 20 mass % rhenium and 0.05 to 10 mass % platinum in relation to the total mass thereof. The inventive method for producing a support for said catalyst consists in a) treating a support which can be eventually pre-treated with the aid of a solution of rhenium compound, b) drying and annealing said support at a temperature ranging from 80 to 600 DEG C, and c) impregnating the support with a solution of platinum compound and in drying it. The inventive method for producing alcohol by catalytic hydrogenation of carbonyl compound on said catalyst is also disclosed.
Abstract:
The invention relates to a method for variable production of mixtures of optionally alkyl-substituted BDO, GBL and THF by two-stage hydrogenation in the gaseous phase of C4-dicarboxylic acids and/or the derivatives thereof, characterized in that a) a gas flow of C4-dicarboxylic acids and/or the derivatives thereof is hydrogenated in a first stage in the gaseous phase on a catalyst at a pressure of 2-100 bars and at a temperature of 200 DEG C to 300 DEG C in a first reactor in the presence of a catalyst in the form of catalyst moulded bodies with a volume of less than 20 mm3, consisting of 5 - 95 wt. % Cu-oxide and 5 - 95 wt. % of an oxide with acid centres in order to form a flow maintly consisting of optionally aryl-substituted GBL and THF, b) succinic anhydride optionally arising therefrom is separated by partial condensation, c) the products THF, water and GBL which remain predominantly in the gaseous phase during said partial condensation are reacted at the same pressure or at a pressure which is reduced in order to reduce flow losses in the hydrogenation circuit at a temperature of 150 to 240 DEG C in a second reactor on a catalyst of > 95 wt. % CuO and 5 to 95 wt. % of one or several oxides selected from the group consisting of ZnO, Al2O3, SiO2, TiO2, ZrO2, CeO2, MgO, CaO, SrO, BaO, La2O3, and Mn2O3 in order to form a mixture consisting of a flow containing BDO, GBL and THF, d) the hydrogen is separated from the products and returned to the hydrogenation, e) the products THF, BDO, GBL and Wasser are separated in a distillatory manner, a flow rich in GBL is optionally returned to the second reactor or is optionally removed therefrom and BDO, THF and GBL are processed in a distillatory manner, and the ratio of the products THF, GBL and BDO is adjusted in relation to each other in the region of 10 to 100 wt. % THF, 0 to 90 wt. % GBL and 0 to 90 wt. % BDO exclusively by varying the temperatures in the two hydrogenation areas, in addition to that of the GBL return flow.
Abstract:
The invention relates to a process for separating off maleic anhydride from a gas stream comprising maleic anhydride, in which a) the gas stream comprising maleic anhydride is brought into contact with a liquid absorbent phase comprising at least one high-boiling inert absorption medium for maleic anhydride and b) maleic anhydride is separated off from the resulting liquid absorbate phase by stripping with a hydrogen-comprising gas as stripping medium in a column, wherein the stripping medium is fed in at two points on the column which are at least one theoretical plate apart.
Abstract:
A process for coproducing alkyl-substituted or unsubstituted THF and pyrrolidones by catalytically hydrogenating C 4 -dicarboxylic acids and/or derivatives thereof in the gas phase in the presence of copper catalysts and reacting GBL with ammonia or primary amines to give pyrrolidones comprises a) hydrogenating C 4 -dicarboxylic acids and/or derivatives thereof in the gas phase at from 200 to 300° C., from 0.1 to 100 bar, catalyst hourly space velocities of from 0.01 to 1 kg of reactant/l of catalyst*hour and reactant/hydrogen molar ratios of from 20 to 800 in the presence of catalysts comprising copper, aluminum and/or zinc to give mixtures of THF and GBL, b) separating the hydrogenation effluent obtained by distillation into a THF/water mixture as the top product and a GBL-containing bottom product, c) separating the THF/water mixture from step b) in a distillation facility consisting of three columns by withdrawing water from the bottom of the first column, recycling water-containing THF from the second into the first column, passing a side stream of the first into the second column, recycling the bottom product of the third column into the first column and withdrawing a distillate at the top of the first column, wherein a side stream of the second column is passed into the third column and the pure THF is obtained as the top product of the third column, d) recovering GBL from the GBL-containing bottom product from step b) by distillation and e) reacting the GBL obtained with ammonia or amines to give corresponding pyrrolidones.
Abstract:
The invention relates to a process for separating off maleic anhydride from a gas stream comprising maleic anhydride, in which a) the gas stream comprising maleic anhydride is brought into contact with a liquid absorbent phase comprising at least one high-boiling inert absorption medium for maleic anhydride and b) maleic anhydride is separated off from the resulting liquid absorbate phase by stripping with a hydrogen-comprising gas as stripping medium in a column, wherein the stripping medium is fed in at two points on the column which are at least one theoretical plate apart.
Abstract:
Crude water-containing tetrahydrofuran is purified by passing the crude tetrahydrofuran through three distillation columns, withdrawing water from the bottom of the first column, recycling water-containing tetrahydrofuran from the top of the second column into the first column, passing a sidestream of the first column into the second column, recycling the bottom product of the third column into the first column, and withdrawing a distillate at the top of the first column. Additionally, a sidestream of the second column is passed into the third column and the purified tetrahydrofuran is recovered as the top product of the third column.
Abstract:
A process for variably preparing mixtures of optionally alkyl-substituted BDO, GBL and THF by two-stage hydrogenation in the gas phase of C 4 dicarboxylic acids and/or derivatives thereof, which comprises a) hydrogenating in a gas phase a gas stream of C 4 dicarboxylic acids and/or derivatives thereof over a particular catalyst at a particular pressure and temperature to give a stream mainly containing of optionally alkyl-substituted GBL and THF, b) removing any succinct anhydride, c) converting the products remaining predominantly in the gas phase in the partial condensation, THF, water and GBL to give a stream comprising a mixture of BDO, GBL and THF, d) removing the hydrogen from the products and recycling it into the hydrogenation, e) distillatively separating the products, THF, BDO, GBL and water, if appropriate recycling a GBL-rich stream or if appropriate discharging it, and working up BDO, THF and GBL distillatively, and setting the ratio of the products, THF, GBL and BDO, relative to one another within the range from 10 to 100% by weight of THF, from 0 to 90% by weight of GBL and from 0 to 90% by weight of BDO only by varying the temperatures in the two hydrogenation zones and also if appropriate the GBL recycle stream.
Abstract:
The invention relates to a method for producing optionally akyl-substituted 1,4-butandiol by two-stage catalytic hydration in the gaseous phase of C4 dicarboxylic acids and/or the derivatives thereof with the steps of: a) introducing a gaseous flow of a C4 dicarboxylic acid or a derivative thereof at 200 to 300 °C and 2 to 60 bar in a first reactor and catalytic gas phase hydration to a mainly optionally alkyl-substituted gamma-butyrolactone containing product; b) introducing the product flow so obtained into a second reactor at a temperature of from 150 °C to 240 °C and a pressure of from 15 to 100 bar and catalytic gas phase hydration to optionally alkyl-substituted 1,4-butandiol; c) removing the desired product from the intermediates, byproducts and possibly not reacted educt; d) optionally returning non-reacted intermediates to one or both hydration stages, whereby in both hydration stages one catalyst each is used which comprises = 5 % by weight, preferably 5 to 95 % by weight, especially 20 to 90 % by weight of an oxidic carrier, the pressure prevailing in the second reactor is higher than in the first reactor, and the product mixture removed from the first reactor is introduced into the second reactor without further purifying it.