摘要:
A process for producing carboxylic acid esters by the following steps:a) preparation of a reaction mixture containing an alcohol and a carboxylic acid and/or a carboxylic anhydride and/or a carboxylic acid ester and or a partially esterified carboxylic acid,b) heating of this mixture to the suitable reaction temperature in the presence of a solid polysiloxane insoluble in the reaction medium and having sulphonic acid groups with intensive thorough mixing accompanied by continuous separation of the reaction water which forms, wherein the polysiloxane used as the catalyst in modified by treatment with a soluble aluminum, titanium or zirconium compound, and the spherical particles thereof have a diameter of 0.01 to 3 mm, a specific surface of 0.1 to 1200 m.sup.2 /g, a specific pore volume of 0.01 to 6.0 ml/g and a bulk density of 50 to 1000 g/l.
摘要:
Disclosed are shell catalysts which contain, on powdered or shaped supports, one or more metals from groups VIII and IB of the Periodic Table of Elements. The catalysts are obtained by coating the support with the catalytically active metals in aqueous solutions of mono- or bimetallic colloids of these metals, wherein the colloids are stabilized by highly hydrophilic surfactants.
摘要:
Disclosed are aqueous solutions of polymeric organosiloxane-ammonium compounds which possess ion exchange properties and a method for manufacture from solid organopolysiloxanes. The solutions are used in the hydrophobing treatment of inorganic materials and building materials.
摘要:
A process is described for the hydrided of halogen-substituted compounds of the second to fourth period of Groups III to V of the periodic system, with the exception of gallium, aluminum, carbon, or nitrogen. A finely-granulated aluminum is added to a molten salt melt that consists of 50-67 molar % AlCl.sub.3 (anhydrous) and 50 to 33 molar % of sodium chloride. Then to the stirred, or by some other means dispersed suspension, hydrogen is introduced to hydrided the finely-dispersed aluminum. Thereafter the mixture is reacted with the halogen-substituted compound and the resulting hydrided compound is renewed.
摘要:
A method for the production of catalytically active coatings on shaped articles of aluminum oxide for the production of hydrogen cyanide according to the BMA method. A suspension is used for the coating which suspension contains at least one platinum metal and aluminum in finely divided elementary form in a carrier liquid. According to especially preferred embodiments, the suspension additionally contains glass frits or organic silicon compounds. After the moistening of the shaped article and evaporation of the carrier liquid, the catalyst is formed during heating to 1000.degree. to 1350.degree. C. in the presence of nitrogen and/or ammonia.Essential advantages of the method over the previously known method of coating with solutions of Pt and Al compounds are: the application of different coating thicknesses are possible in a single coating stage, the previously-necessary hydrogenation stage after each impregnation is eliminated and the health risk is reduced.
摘要:
The invention is directed to silylalkyl and silylaralkyl substituted cyclopentadienes which have a hydrolyzable group attached to the silicone atom, a process for their production and peroxide cross-linkable synthetic resin and rubber mixtures containing them.
摘要:
Polymeric tertiary and secondary amines as described with a silica-type backbone, comprising units of the formula: ##STR1## in which R.sup.1 and R.sup.2 represent a group ##STR2## R.sup.4 is alkylene and the free valencies of the oxygen atoms are saturated by silicon atoms of further groups (2), if appropriate with incorporation of crosslinking agents, R.sup.3 has the same meaning as R.sup.1 and R.sup.2, or it represents hydrogen, alkyl, cycloalkyl or benzyl. Also disclosed are processes for preparing the polymeric tertiary and secondary amines and the use of these materials for removing acids from liquids and gases.
摘要:
Propyl silanes functionalized in 3-position are produced by catalytically reacting allyl compounds of the formula H2C═CH—CH2X with silanes of the formula R2R3R4SiH and using a 3- to 100-fold excess of silane.
摘要:
Compacts based on pyrogenically produced silicon dioxide and having the following physical and chemical characteristics: Outer diameter 0.8-20 mm BET surface area 30-400 m2/g Pore volume 0.5-1.3 ml/g Breaking strength 10-250N Composition >99.8 wt. % SiO2 Other constituents
摘要:
Shaped organosiloxane amine copolycondensates are described which contain Pd, Pt, Ru and/or Rh, as well as optional promotors and/or moderators. The shaped copolycondensate function as a carrier for metals and are made up of units of: ##STR1## and/or units of Y--R.sup.6. R.sup.2 to R.sup.6 are a group represented by the formula: ##STR2## wherein R.sup.7 is a group bound to N, X, or Y (for example, an alkylene group) and R.sup.1 is R.sup.7 --SiO.sub.3/2, H, CH.sub.3, C.sub.2 H.sub.5, or C.sub.3 H.sub.7. X stands for a double-bonded group such as --S--, --S.sub.2 --, --S.sub.3 --, --S.sub.4 --, --HN--CS--NH-- and Y stands for a monovalent groups such as --CN, --SCN, --SH, --S--CH.sub.3, --NH.sub.2, --NH--(CH.sub.2).sub.2 --NH.sub.2. The carrier substance may be cross-linked with cross-linking agents containing Si, Ti, Zr or Al. The metal-containing product is spherical in form and is defined by the parameters of sphere diameter, specific surface and pore volume as well as bulk density. Methods of production and use of the copolycondensates are also described.