Abstract: Process for producing fumed silica powder with a decreased silanol group density, comprising subjecting a fumed surface untreated silica powder with a silanol density dSiOH of at least 1.2 SiOH/nm2 and a particle size d90 of not more than 10 ?m, to thermal treatment at a temperature of 350° C. to 1250° C. for 5 min to 5 h, wherein the temperature and the duration of the thermal treatment are chosen so that dSiOH of the silica is decreased by 10%-70% relative to dSiOH of the employed thermally untreated silica, wherein the thermal treatment is carried out while the fumed silica powder is in motion, followed by optional surface treatment. Surface unmodified and modified fumed silica powders obtained by this process and the use thereof.

Abstract: Methacrolein is prepared in a continuous process by a Mannich condensation reaction of formaldehyde with propanal. A methacrolein polymerization inhibitor is introduced during the production process and a part thereof is recycled back into the reactor where the Mannich condensation reaction is carried out.

Abstract: The invention provides fumed silica granules having a BET surface area of 20 m2/g to 500 m2/g; a number average particle size d50 of 350 ?m to 2000 ?m; a span (d90?d10)/d50 of particle size distribution of 0.8-3.0; a bulk density of more than 0.35 g/mL; a pore volume for pores >4 nm of not more than 1.5 cm3/g, process for its preparation and use thereof as a catalyst carrier, a carrier for liquid substances, in cosmetic applications, for thermal insulation, as pharmaceutical excipient, in producing thermally treated silica granules, as an abrasive, as a component of a silicone rubber.

Abstract: The invention relates to a process for preparing a carboxylic ester by reacting an aldehyde in the presence of an aluminum alkoxide, wherein the aluminum alkoxide is obtained either by reacting an aluminum hydride with an aldehyde or by reacting a different aluminum alkoxide with a carboxylic ester.

Abstract: The present invention relates to a process for producing silica-based thermal insulation moulded body comprising at least 50% by weight of synthetic amorphous silica and not more than 50% by weight of natural silica with a specified particle size, thermal insulation moulded body obtainable by this process and the use thereof for thermal and/or acoustic insulation.

Abstract: Fumed silica powder, surface treated with a surface treatment agent selected from the group consisting of organosilanes, silazanes, acyclic polysiloxanes, cyclic polysiloxanes, and mixtures thereof, wherein the powder has: a) a number of silanol groups relative to BET surface area dSiOH of at least 0.85 SiOH/nm2, as determined by reaction with lithium aluminium hydride; b) a methanol wettability of more than 40% by volume of methanol in methanol-water mixture; c) a tamped density of not more than 200 g/L.

Abstract: Silica-based hydrophobic granular material with an increased polarity Silica-based granular material, comprising silica and at least one IR-opacifier, hydrophobized with a surface treatment agent comprising a silicon atom, wherein the granular material has: a) a cumulative pore volume of pores>4 nm of more than 2.5 cm3/g, as determined by the mercury intrusion method according to DIN ISO 15901-1; b) a tamped density of 140 g/L to 290 g/L; c) a number of silanol groups relative to BET surface area dSiOH of at least 0.5 SiOH/nm2, as determined by reaction with lithium aluminium hydride. d) a number of silicon atoms in the surface treatment agent relative to BET surface area d[Si] of at least 1.0 [Si atoms]/nm2.

Abstract: Surface-treated fumed silica, with a tribo-electro static charge of ?500 ?C/g to +500 ?C/g, a ratio of the tribo-electro static charge to BET surface area of ?3.5 ?C/m2 to +3.5 ?C/m2, a methanol wettability of at least 20% by volume methanol in methanol/water mixture, a ratio of carbon content to BET surface area of at most 0.020 wt. %*g/m2, a process for its preparation and the use thereof.

Abstract: Methacrolein is prepared in a continuous process by a Mannich condensation reaction of formaldehyde with propanal. A methacrolein polymerization inhibitor is introduced during the production process and a part thereof is recycled back into the reactor where the Mannich condensation reaction is carried out.

Abstract: The present invention relates to a novel process for performing a heterogeneously catalyzed reaction for oxidative esterification of aldehydes to give carboxylic esters. Against this background, it has been possible by the present process according to the invention to perform such processes for longer periods without disruption, with constant or even increased activities and selectivities. This gives rise to the possibility of performing such processes in a very simple, economically viable and environmentally benign manner.

Abstract: The invention relates to a process for preparing a carboxylic ester by reacting an aldehyde in the presence of an aluminum alkoxide, wherein the aluminum alkoxide is obtained either by reacting an aluminum hydride with an aldehyde or by reacting a different aluminum alkoxide with a carboxylic ester.

Abstract: The invention relates to a process for preparing a carboxylic ester by reacting an aldehyde in the presence of an aluminum alkoxide, wherein the aluminum alkoxide is obtained either by reacting an aluminum hydride with an aldehyde or by reacting a different aluminum alkoxide with a carboxylic ester.

Abstract: The present invention relates to a novel process for performing a heterogeneously catalyzed reaction for oxidative esterification of aldehydes to give carboxylic esters. Against this background, it has been possible by the present process according to the invention to perform such processes for longer periods without disruption, with constant or even increased activities and selectivities. This gives rise to the possibility of performing such processes in a very simple, economically viable and environmentally benign manner.

Abstract: The present invention relates to novel catalysts for oxidative esterification, by means of which, for example, (meth)acrolein can be converted to methyl (meth)acrylate. The catalysts of the invention are especially notable for high mechanical and chemical stability even over very long periods. This especially relates to an improvement in the catalyst service life, activity and selectivity over prior art catalysts which lose activity and/or selectivity relatively quickly in continuous operation in media having even a small water content.

Abstract: The present invention relates to a process for producing methyl methacrylate, comprising the following steps: A) producing methacrolein and B) reacting the methacrolein obtained in step A) in an oxidative esterification reaction to give methyl methacrylate, characterized in that the two steps A) and B) take place in a liquid phase at a pressure of from 2 to 100 bar, and step B) is carried out in the presence of a heterogeneous noble-metal-containing catalyst comprising metals and/or comprising metal oxides.

Abstract: The invention relates to a process for preparing a carboxylic ester by reacting an aldehyde in the presence of an aluminum alkoxide, wherein the aluminum alkoxide is obtained either by reacting an aluminum hydride with an aldehyde or by reacting a different aluminum alkoxide with a carboxylic ester.

Abstract: A method can prepare a carboxylic ester. The method includes reacting an aldehyde in the presence of an aluminium alkoxide applied to a support material.

Abstract: A process for performing a heterogeneously catalysed reaction in a three-phase reactor, where there is at least one liquid phase, at least one gaseous phase and at least one solid phase in the reactor and the reactor has at least two zones, with the reaction mixture being conveyed downward in zone 1, the reaction mixture being conveyed upward in zone 2, zones 1 and 2 being separated from one another by a dividing wall, and in that the ratio between the average catalyst concentrations in zone 2 and in zone 1 is greater than 2.

Abstract: The present invention relates to a process for preparing alkyl methacrylates, especially MMA, and methacrylic acid, based on methacrolein, which has been oxidatively esterified in a second process stage. Methacrolein is obtainable in principle from C2 and C4 units. The present process has the advantage that the alkyl methacrylate and methacrylic acid can be obtained in a simple manner, in high yields and high purities, either as a mixture or as isolated product streams. In particular, the process of the invention has the great advantage that especially the ratio of the desired methacrylic acid and alkyl methacrylate, especially MMA, products can be adjusted freely within a wide range and varied by chemical engineering measures and operating parameters.

Abstract: The present invention relates to a process for producing methyl methacrylate, comprising the following steps: A) producing methacrolein and B) reacting the methacrolein obtained in step A) in an oxidative esterification reaction to give methyl methacrylate, characterized in that the two steps A) and B) take place in a liquid phase at a pressure of from 2 to 100 bar, and step B) is carried out in the presence of a heterogeneous noble-metal-containing catalyst comprising metals and/or comprising metal oxides.