Abstract: The present invention relates to a process for continuous purification of yellow phosphorus by adsorption onto activated carbon.

Abstract: The present invention relates to a process for continuous purification of yellow phosphorus by adsorption onto activated carbon.

Abstract: The invention relates to a composite foam comprising from 10 to 90% by volume of SiO.sub.2 aerogel particles and from 90 to 10% by volume of a foam, preferably a polyurethane and/or polyolefin foam, a process for its preparation and its use.

Abstract: Process for the preparation of aerogels by subcritical drying of inorganic and organic hydrogels and lyogels to give aerogels, dielectric drying methods being used.

Abstract: Xerogels and a process for their preparation involving acidifying an aqueous waterglass solution, polycondensing the resulting silica by addition of a base, removing most of the water from the gel by washing the gel with an organic solvent, reacting the resulting gel with a silylation agent and then drying the silylated gel under subcritical conditions.

Abstract: The invention relates to a process for preparing modified SiO.sub.2 gels, in which the gel is aged using a solution of a condensable alkyl and/or aryl orthosilicate, or using an aqueous silicic acid solution, in order to strengthen the structure of the gel.

Abstract: Process for the preparation of aerogels by subcritical drying of inorganic and organic hydrogels and lyogels to give aerogels, dielectric drying methods being used.

Abstract: The invention relates to modified SiO.sub.2 gels (xerogels), the preparation thereof and the use thereof as thermal insulators. The xerogels are prepared by acidifying an aqueous waterglass solution, polycondensing the silicic acid produced thereby, by adding a base, to an SiO.sub.2 gel, removing the water from the resulting gel by extractive distillation with an organic solvent which forms with water an azeotrope which separates on cooling into two phases, reacting the gel with a silylating agent, and then drying at pressures and temperatures which are below the critical pressure and/or the critical temperature of the organic solvent used for removing the water.

Abstract: Process for removing olefinic impurities from 2H-heptafluoropropane (R 227).The invention relates to a process for removing olefinic impurities from 2H-heptafluoropropane (R 227) by passing the contaminated R 227 in the gas phase at from -20.degree. to 100.degree. C. over aluminum oxide.

Abstract: The invention relates to a process for the preparation of saturated hydrofluorocarbons by hydrogenating at least one (hydro)fluorocarbon of the formula (I)R.sub.f --CH.sub.n Cl.sub.c Br.sub.d I.sub.e (I)in whichR.sub.f is C.sub.a F.sub.(2a-b)+1 H.sub.b where a is 1-4 and b is 0-4,n is 0-2c is 0-3d is 0-3e is 0-3c+d+e is 3-n,catalytically with hydrogen at elevated temperature.

Abstract: Process for the removal of olefinic impurities from 1,1,1,2,3,3,3-heptafluoropropaneThe invention relates to a process for the removal of olefinic impurities from 1,1,1,2,3,3,3-heptafluoropropane (R 227) in which the contaminated R 227 is brought into contact with an alcohol and a base, and the R 227 is simultaneously or subsequently removed by distillation.

Abstract: A process for disposing of bromofluorocarbons, bromochlorofluorocarbons, or mixtures of any of bromofluorocarbons, bromochlorofluorocarbons, fluorocarbons, or chlorofluorocarbons. The process comprises thermally cleaving halons, halon-containing fluorocarbons, or halon containing chlorofluorocarbons, cooling the resulting gas stream, oxidizing the resulting hydrogen bromide to bromine by feeding excess elemental chlorine into the gas stream, absorbing the resulting HF or HCl from the gas stream with recovery of hydrofluoric acid or hydrochloric acid, and finally separating elemental bromine and chlorine from each other by distillation or reducing both to give the salts.

Abstract: The invention relates to a process for removing olefinic impurities from hydrogen-containing chlorofluorohydrocarbons (HCFCs) in which the contaminated HCFCs are passed in the gas phase at 200.degree. to 400.degree. C. over a zeolite.

Abstract: The invention relates to a process for the removal of olefins of the formula C.sub.n H.sub.x F.sub.y A.sub.z, in which A is chlorine and/or bromine and n is a number from 2 to 4, x and y are each a number from 1 to 6 and z is a number from 1 to 4, the sum of x+y+z being equal to 2n, from hydrochlorofluorocarbons of the formula C.sub.2 H.sub.m F.sub.p A.sub.q, in which A is chlorine and/or bromine and m and p are each a number from 1 to 5 and q is a number from 0 to 4, the sum of m+p+q being equal to 6, which comprises reacting the hydrochlorofluorocarbons C.sub.2 H.sub.m F.sub.p A.sub.q which are contaminated with the olefins mentioned, in the presence of oxygen-containing phase-transfer catalysts with complex hydrides and/or strong bases.