Abstract: A process is described for preparing esters of an acid component selected from among polybasic C4-C10 carboxylic acids and an alcohol component selected from among C3-C12 alkanols or from among C3-C12 alkanediols, the alkyl chain of which may have interruption by from 1 to 3 oxygen atoms, by a) heating at boiling point, in a reaction zone and in the presence of an esterification catalyst, a mixture essentially consisting of the acid component or of an anhydride thereof and of the alcohol component, b) using rectification to separate the vapor comprising alcohol and water into an alcohol-rich fraction and a water-rich fraction, and c) returning the alcohol-rich fraction into the reaction zone and conducting the water-rich fraction out of the process. The process is simple to carry out and permits rapid achievement of essentially quantitative conversion.

Abstract: A process is described for preparing mixtures of diesters of phthalic acid with decanols and tridecanols by reacting phthalic acid or a reactive derivative of phthalic acid with a mixture made from at least one decanol and at least one tridecanol. Mixtures obtainable in this way are also described, as is their use as plasticizers for molding compositions, and also mixtures of isomeric tridecanols suitable for preparing the mixtures of diesters.

Abstract: The invention relates to a method for the production of phthalic anhydride to a specification, using a distillative purification of crude phthalic anhydride, by introduction of crude phthalic anhydride into a distillation column, operating at reduced pressure, withdrawal of the low-boiling fraction from the head, or near the head of the column and withdrawal of the phthalic anhydride, which meets the specification, from a side-tap on the column, whilst operating the column at a reflux ratio x, with 1:1.7<x<1:3.

Abstract: The invention relates to a method and a device for cleaning flowing gases. To reduce the total emissions, nitrogen oxides, especially NO and NOx, are extracted at least partially from the gas to be scrubbed, in the temperature range from 50 and 300° C., preferably between 50 and 150° C. To extract the nitrogen oxides, an intermediate storage medium is used that is composed of a storage material and a supporting material for the storage material. The intermediate storage medium having in particular a composition of the formal chemical formula Ag.CuAl2O4 in an Al2O3 matrix, with the composition being a spinel or being of the spinel type, and with the composition having characteristic spinel lines in the x-ray spectrum, where 0≦x<1.

Abstract: A process is described for preparing esters of an acid component selected from among polybasic C4-C10 carboxylic acids and an alcohol component selected from among C3-C12 alkanols or from among C3-C12 alkanediols, the alkyl chain of which may have interruption by from 1 to 3 oxygen atoms, by a) heating at boiling point, in a reaction zone and in the presence of an esterification catalyst, a mixture essentially consisting of the acid component or of an anhydride thereof and of the alcohol component, b) using rectification to separate the vapor comprising alcohol and water into an alcohol-rich fraction and a water-rich fraction, and c) returning the alcohol-rich fraction into the reaction zone and conducting the water-rich fraction out of the process. The process is simple to carry out and permits rapid achievement of essentially quantitative conversion.

Abstract: A process is described for preparing mixtures of diesters of phthalic acid with decanols and tridecanols by reacting phthalic acid or a reactive derivative of phthalic acid with a mixture made from at least one decanol and at least one tridecanol.

Abstract: Polyesters suitable as plasticizers and obtainable by reacting aliphatic dicarboxylic acids, neopentyl glycol, at least one other diol and a nonanol mixture, where the nonanol mixture is mainly composed of 1-nonanol, of monomethyloctanols, of dimethylheptanols and of monoethylheptanols. The nonanol mixture is also described, as is the use of the plasticizers.

Abstract: Polyesters suitable as plasticizers and obtainable by reacting aliphatic dicarboxylic acids, neopentyl glycol, at least one other diol and a nonanol mixture, where the nonanol mixture is mainly composed of 1-nonanol, of monomethyloctanols, of dimethylheptanols and of monoethylheptanols.

Abstract: An exhaust gas purification device includes a porous body of catalytic material of the general formula AaBbO4 disposed in an exhaust gas stream of an engine. The porous body of catalytic material has a characteristic response temperature above which it is catalytically active to reduce pollutants in the presence of a reducing agent. The porous body stores at least 20% by volume hydrocarbons at temperatures below the response temperature. A represent at least one element selected from Mg, Ca, Mn, Fe, Ni, Co, Cu, Zn, Sn, Ti and A+B is less than 3, A is greater than 0 and B greater than 0.

Abstract: The mixture described is a mixture of isomeric nonanol diesters of a dicarboxylic acid, selected from the class consisting of a mixture of diesters of adipic acid in the 1H NMR spectrum of which, observed in CDCl3, the ratio of the area under the resonance signals at chemical shifts in the range from 1.0 to 2.0 ppm with respect to TMS to the area under the resonance signals at chemical shifts in the range from 0.5 to 1.0 ppm with respect to TMS is from 1.20 to 5.00 and a mixture of diesters of phthalic acid, in the 1H NMR spectrum of which, observed in CDCl3, the ratio of the area under the resonance signals at chemical shifts in the range from 1.1 to 3.0 ppm with respect to TMS to the area under the resonance signals at chemical shifts in the range from 0.5 to 1.1 ppm with respect to TMS is from 1.00 to 4.00.

Abstract: A storage catalyst includes (1) a component that has a catalytic reducing action for nitrogen oxides at least in the presence of hydrocarbons, and (2) a component that stores NOx at least at temperatures of below 100° C. The catalytically active component is of the general chemical formula AaBbO4, where A is one or more divalent metals and B is one or more trivalent metals, and where a+b≦3 and a, b>0. The reaction enthalpy or the chemical activity between the catalytically active component and the NOx-storing component is low at least up to temperatures of 600° C.

Abstract: The present invention is directed to a purification device that includes a porous body and a catalyst. To reduce the emission of pollutants, a pollutant-containing stream of gas flows through the porous body.

Abstract: A process for the catalytic reduction of NO.sub.x, the reduction taking place in the presence of a catalyst which comprises(a) from 20 to 97 wt % of A.sub.2 O.sub.3,(b) from 1 to 40 wt % of CuO,(c) from 1 to 50 wt % of ZnO,(d) from 1 to 40 wt % of Ag,(e) from 0 to 2 wt % of Pt,(f) from 0 to 20 wt % of oxides of rare earth metals, elements of the 3rd subgroup of the Periodic Table of the Elements or mixtures thereof,based on the total weight of the components (a) to (e), which adds up to 100 wt %, wherein, in each case, up to half the weight of the component (a) may be replaced by Fe.sub.2 O.sub.3, Cr.sub.2 O.sub.3, Ga.sub.2 O.sub.3 or mixtures thereof, of the component (b) by CoO, of the component (c) by MgO, of the component (d) by Au and of the component (e) by Pd, Ru, Os, Ir, Rh, Re or mixtures thereof, is used for reducing NO.sub.x, especially in combustion off-gases, the components (a), (b) and (c) forming a spinel which is doped with the components (d), (e) and (f).

Abstract: NO.sub.x, where x is 1 and 2, in exhaust gases is reduced over heterogeneous catalysts with hydrocarbons, carbon monoxide, hydrogen or mixtures thereof in the presence of oxygen from 100 to 650.degree. C. and an absolute pressure of from 0.5 to 50 bar by a process in which the heterogeneous catalysts used are bimodal or polymodal compounds of the general formula IA.sub.1-x M.sub.2 O.sub.4 (I),which, if required, are doped with rare earth metals, noble metal, titanium, vanadium, molybdenum, tungsten or mixtures thereof, and whereA is magnesium, calcium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, tin or mixtures thereof,M is aluminum, gallium, indium, tin, chromium, manganese, iron, cobalt, nickel, copper, zinc or mixtures thereof andx is from 0 to 0.

Abstract: A method of catalytically reducing nitrogen oxides (NO.sub.x) and oxidizing hydrocarbons or carbon monoxide in exhaust gases of internal combustion engines or combustion power plants using a catalyst comprising a magnesium oxide/copper oxide/aluminum oxide spinel or a copper-impregnated copper oxide/aluminum oxide spinel.

Abstract: The present invention relates to a method for operating a catalyst for gases, especially for exhaust gases of stoichiometrically operated gasoline engines, wherein a catalyst is exposed to a gas stream and pollutants are catalytically converted. To improve the elimination of pollutants in the starting phase, hydrocarbons present in the gas are temporarily stored by the catalyst at temperatures below a response temperature of the catalyst, particularly below 200.degree. C., and preferably below 150.degree. C. The hydrocarbons are then released at temperatures above the response temperature and the pollutants, such as nitrogen oxides, are catalytically converted with reducing agents, such as hydrocarbons, carbon monoxide and mixtures thereof. The catalyst is a spinel, such as (MgCu)Al.sub.2 O.sub.4, which may also include a catalytically active species, such as WO.sub.3, V.sub.2 O.sub.5 and TiO.sub.2.

Abstract: A process for selective catalytic reduction of nitrogen oxides from exhaust gases, preferably those from diesel engines in vehicles, using pulsed superstoichiometric addition of NH.sub.3 or NH.sub.3 -releasing substances, comprises controlling the pulsed superstoichiometric addition of NH.sub.3 in such a way that, after it has started, the addition is interrupted again only when the amount of NH.sub.3 stored in the catalyst has reached a specific upper threshold value which is predetermined in accordance with the catalyst properties and the catalyst volume, the amount of NH.sub.3 stored being calculated from the difference between the metered amount of NH.sub.3 and the amount of NO.sub.x separated off, which is determined from the NO.sub.x concentration in the exhaust gas and the average degree of separation, and the addition of NH.sub.3 is resumed only when the amount of NH.sub.

Abstract: The present invention relates to a method for operating a purification device, to a purification device and to the use of same. To reduce the emission of pollutants, a filter body through which a fluid can flow and comprising a catalyst, is exposed to a stream of gas which is to be purified. Before the gas enters the catalyst, a reducing agent is added in the flow direction of the gas, and after a certain treatment point, during which the gas, which is to be purified, is flowing in the catalyst, reducing agent is added once more to the flowing gas by a feeding mechanism and contact with the catalyst is maintained.

Abstract: A catalyst and a method for producing the catalyst, for catalytic reduction of NO.sub.x and oxidation of hydrocarbons, the catalyst comprises a zinc, copper and aluminum spinel to which, at least one element selected from palladium, platinum, rhodium, ruthenium, osmium, iridium, rhenium and/or rare earth metals, such as lanthanum and cerium, vanadium, titanium, niobium, molybdenum, tungsten and/or salts thereof and/or oxides thereof has been added.

Abstract: The invention relates to a method and a device for cleaning flowing gases. To reduce the total emissions, nitrogen oxides, especially NO and NOx, are extracted at least partially from the gas to be scrubbed, in the temperature range from 50 and 300.degree. C., preferably between 50 and 150.degree. C. To extract the nitrogen oxides, an intermediate storage medium is used that is composed of a storage material and a supporting material for the storage material. The intermediate storage medium having in particular a composition of the formal chemical formula Ag.CuAl.sub.2 O.sub.4 in an Al.sub.2 O.sub.3 matrix, with the composition being a spinel or being of the spinel type, and with the composition having characteristic spinel lines in the x-ray spectrum, where 0.ltoreq.x<1.