Abstract: A process is disclosed for lowering nitrogen oxide levels in combustion engine exhaust gas by a reduction catalyst and by controlling the exhaust gas temperature upstream from the catalyst to a constant value, at which the catalyst exhibits maximum conversion for nitrogen oxides. It is possible to maintain maximum conversion over a wide range of engine outlet temperatures of the exhaust gas.

Abstract: Relatively resilient flux encasings for solder preforms are obtained when a mixture of 5 to 30 wt. % potassium silicate having a molar ratio of K.sub.2 O:SiO.sub.2 ranging from 1:2.5 to 1:4.5, 0.5 to 10 wt. % concentrated phosphoric acid, 0.1 to 5 wt. % boric acid and 0 to 10 wt. % finely divided silicon dioxide, with the remainder water, is used as the binder.

Abstract: Reactor heads for the feed and withdrawal of a fuel gas/air mixture and of an educt gas mixture into the heating ducts and reaction ducts respectively of a monolithic countercurrent reactor. The reactor heads are provided with guide pipes, which feed the gas mixtures into the ducts assigned to them and withdraw them from these ducts.

Abstract: The invention relates to amphiphilic compounds of the general formula I ##STR1## with at least two hydrophilic and at least two hydrophobic groups based on alkoxylated amines and/or alkoxylated fatty acid amides and di-, oligo- or polycarboxylic acids (spacer A). Y and Z are hydrogen or functional groups. The amphiphilic compounds according to this invention are usually surface-active and are suitable as emulsifiers, demulsifiers, detergents, dispersants and hydrotropes in industry and domestically, for example in the areas of metal processing, ore production, surface treatment, washing and cleaning hard surfaces, such as, for example, the manual cleaning of crockery, washing and cleaning skin and hair, cosmetics, medicine and food processing and preparation.

Abstract: A coating dispersion is shown for the production of catalysis-promoting coatings on an inert, structure-reinforcing element. The solids of the dispersion are present in various particle fractions and lead to a relatively rough coating surface with improved exchange between the exhaust gas and the catalyst surface. This results in improved heat-up behavior of the catalyst.

Abstract: Silica with the following physico-chemical properties:______________________________________ Specific surface m.sup.2 /g 80-400 Primary particle size nm 7-40 Tapped density g/l 50-300 pH value 3-10 Carbon content % 0.1-15 DBP number % <200 ______________________________________is produced by spraying a silica under intensive mixing, optionally with water or dilute acid at first and then with a surface-modifying reagent or a mixture of several surface-modifying reagents, then mixing, tempering, and subsequently destructuring/compressing and grinding.

Abstract: The use of modified silicon dioxide as a catalyst support in catalytic reactions under hydrothermal conditions is described. The pore structure of the supports may be stabilized against hydrothermal reaction conditions by impregnating the catalyst supports with elements of Group IVB of the Periodic Tube of Elements.

Abstract: An emptying device for bulk bags having an inner and outer sack in which disturbances during emptying and contact with the bulk material are avoided. The device includes a holding device for the bulk bag, a double tube device arranged centrally beneath the holding device and having an inner tube, an outer tube arranged around the inner tube with an outlet fitted to its lower edge, and a closing ring which can be raised and lowered for closing the upper end of the annular gap formed by the two tubes. The device can additionally include at least one gripping device for securing the sack outlet of the inner sack, which gripping device can be moved up and down within the inner tube and can be pulled downwards by means of a pulling device operable from outside the double tube device.

Abstract: A mixture of oligomers of alkylalkoxysilanes condensed in the chain and/or cyclic form, said mixture of oligomers containing less than 2% by weight of free alcohols and the condensed alkoxysilanes satisfying formula I: ##STR1## wherein R is an alkyl group having 3 to 18 carbon atoms, and each R' is a member (i) selected from the group consisting of methyl, ethyl or hydrogen, or is (ii) methyl or hydrogen, or is (iii) ethyl or hydrogen, the degree of oligomerization being in the range 2.ltoreq.x.ltoreq.20 and the quotient of the molar ratio ?Si/alkoxy group!.gtoreq.1; and/orsatisfying formula II: ##STR2## in which R is an alkyl group having 3 to 18 carbon atoms, and each R' is a member (i) selected from the group consisting of methyl, ethyl or hydrogen, or is (ii) methyl or hydrogen or is (iii) ethyl or hydrogen, the degree of oligomerization being x.gtoreq.3 and the quotient of the molar ratio ?Si/alkoxy group!.gtoreq.1.

Abstract: A catalyst for purifying the exhaust gases from diesel engines. The catalyst contains a zeolite mixture of several zeolites with different moduli and platinum group metals as well as further metal oxides from the group aluminum silicate, aluminum oxide and titanium oxide, wherein the aluminum silicate has a ratio by weight of silicon dioxide to aluminum oxide of 0.005 to 1 and the platinum group metals are deposited on only the further metal oxides.

Abstract: Acrolein-releasing emulsion homopolymers release acrolein in aqueous systems. They are produced by adding acrolein, at least 95% by weight pure, to a solution of an alkali hydroxide, with the temperature not exceeding 25.degree. C. during the addition, and then adjusting the pH to 5 to 7 by adding a mineral acid.

Abstract: A process is disclosed for the purification of an off-gas which originates from the oxidation of xylene with air in the Witten process for the preparation of dimethyl terephthalate by subjecting the off-gas to a partial condensation step to remove constituents such as dimethyl terephthalate and xylene; then contacting the off-gas with a solvent such as para-toluic acid or a mixture of para-toluic acid and methyl benzoate so as to remove contaminants such as para-xylene out of the off-gas; then contacting the off-gas with a solvent such as methyl benzoate to remove contaminants such as methyl para-toluate out of the off-gas; then contacting the off-gas with water so as to remove contaminants such as methanol out of the off-gas, and then combusting the off-gas.

Abstract: The invention relates to a process for the removal of HCN from gas mixtures that contain at least HCN and sulfur compounds, especially from gas mixtures that are obtained by partial oxidation of hydrocarbons, by catalytic decomposition of HCN, as well as a catalyst for the decomposition of HCN. According to the invention, the gas mixture is brought into contact with a catalyst which decomposes the HCN by hydrogenation and/or by hydrolysis and COS that is contained in the gas mixture is decomposed at least partially in this catalyst by hydrolysis. Advantageously, a catalyst that is based on titanium oxide and/or zirconium oxide as a vehicle and that contains chromium oxide as an active component is used. Advantageously, the catalyst is reduced during catalyst production or before use with H.sub.2 and/or a reducing gas at temperatures above the operating temperature of catalytic decomposition.

Abstract: In the purification of an off-gas stream originating from a process of oxidizing a liquid mixture of para-xylene with methyl para-toluate with an oxygen-containing gas under pressure, the off-gas being contaminated with at least one of an aliphatic and an aromatic impurity, which comprises expanding the off-gas stream in an expansion turbine for generating mechanical or electrical energy so as to obtain an at least partial recovery of the energy contained in the off-gas, the improvement comprising subjecting the off-gas to at least one absorption step under pressure to remove at least one component from the off-gas and subjecting the resultant off-gas stream to combustion under a pressure of more than 3 bar prior to expanding the off-gas stream in the expansion turbine.

Abstract: Disclosed are organosilane polycondensation products prepared by hydrolysis of an hydrogen salt of an aminosilane compound or by hydrolysis of an aminosilane followed by reaction with an alkyl salt. The compounds are useful in forming stable aqueous solutions and as adhesion promoters between inorganic and organic surfaces.

Abstract: Novel dialkyl 2-haloethyl malonates are prepared from a dialkyl cyclopropane-1,1-dicarboxylate by reaction with a hydrogen halide in the presence of a 1,2-dialkoxy ethane as a solvent and of a Friedel-Crafts catalyst.

Abstract: A binder composition for storable zinc dust paints contains a mixture of silicic acid esters, solvents, curing agents, an antideposition agent, and a dearomatized aliphatic hydrocarbon mixture with an average molecular weight of 133. The binder composition has a flash point distinctly higher than 21.degree. C.

Abstract: The content of decomposable organic carbon compounds present in a gaseous phase is determined down to the parts per billion (10.sup.-9) range and in special cases down to the parts per trillion (10.sup.-12) range. The gaseous sample material being tested is introduced into a limited quantity of water wherein the organic compounds are photolytically decomposed. The decomposition products are ascertained in the carrier gas and/or in the limited quantity of water.

Abstract: Dialkyl cyclopropane-1,1-dicarboxylates are prepared from a dialkyl malonate, a 1,2-dichloroalkane and finely divided potassium carbonate while azeotropically removing the water released by the reaction.

Abstract: The content of decomposable organic carbon compounds present in a gaseous phase is determined down to the parts per billion (10.sup.-9) range and in special cases down to the parts per trillion (10.sup.-12) range. The gaseous sample material being tested is introduced into a limited quantity of water wherein the organic compounds are photolytically decomposed. The decomposition products are ascertained in the carrier gas and/or in the limited quantity of water.