Abstract:
Para-substituted o-benzylphenols are prepared by reacting p-substituted phenols with benzylating agents in the presence of zeolites of the faujasite type at elevated temperature.
Abstract:
4-Methyl-2-cyclohexylphenol can be prepared by alkylation of p-cresol with cyclohexanol or cyclohexene by performing the reaction in the liquid phase in the presence of 1-10% by weight, based on the amount of p-cresol, of a large pore, acidic zeolite.
Abstract:
Iodine and organic iodine compounds which may be radioactive and which may be found in waste gases or vapors from nuclear reactors can be removed from such gases or vapors by passing the iodine or organic iodine compound-containing gases or vapors through a layer of binder-free silver-exchanged molecular sieve granulates of the faujasite type.
Abstract:
The present invention relates to a new zeolite material having a composition (molar ratios of the oxides) corresponding to the formula:M.sub.2/n O.Al.sub.2 O.sub.3.(20-150) SiO.sub.2(M represents n-valent cation) to a process for the production thereof using hexamethylene imine and to the use of the zeolite material as a catalyst in the conversion of methanol and/or dimethyl ether to hydrocarbons.
Abstract:
A lacquer comprising an organic binder, at least one pigment or filler, and a zeolite in an amount sufficient to increase the dispersibility of the pigment or filler. Advantageously the pigment is at least one of titanium dioxide, iron oxide and mixed-phase rutile, and the binder is a polyester. Desirably the pigment is present in from about 1 to 5% by volume of the pigment plus any filler and its average particle size is from about 1 to 3 .mu.m.
Abstract:
A process for the production of synthetic zeolite with the crystal structure of faujasite and with a composition corresponding to the formula:Na.sub.2 O . Al.sub.2 O.sub.3 . (2.5 .+-. 0.5) SiO.sub.2 . n H.sub.2 O(n = 0 to 8)comprising forming a reaction mixture containing Na.sub.2 O, Al.sub.2 O.sub.3, SiO.sub.2 and H.sub.2 O at a temperature of about 60.degree. to 105.degree. C in the presence of about 1 to 20% of finely divided zeolite A based on the weight of Na.sub.2 O + Al.sub.2 O.sub.3 + SiO.sub.2, thereby to form a precipitate which crystallizes to form a synthetic zeolite of faujasite structure. Advantageously the molar ratios of the oxides in the reaction mixture, exclusive of the added zeolite A, are approximately:SiO.sub.2 /Al.sub.2 O.sub.3 = 3 to 5Na.sub.2 O/SiO.sub.2 = 1.2 to 1.5H.sub.2 O/Na.sub.2 O = 35 to 45.Even if the mass is stirred during crystallization, little or no phillipsite is produced.
Abstract:
Methods comprising: (a) providing a silica sol having a BET surface area of 15 to 1000 m2/g and a solids content of up to 45% by weight of silicon dioxide, based on the silica sol; (b) mixing the silica sol and an anionic polyether carboxylate to form a mixture, wherein the anionic polyether carboxylate is mixed with the silica sol in an amount of 0.01 to 10% by weight, based on the mixture; and (c) concentrating the mixture to form a concentrated mixture having a solids content of 20 to 70% by weight of silicon dioxide, based on the concentrated mixture; and the concentrated sols prepared thereby.
Abstract:
A process of preparing a silica sol is described. The process involves reacting a fresh sol with guanidine carbonate. The reaction may be conducted in the presence of a base (e.g., sodium water glass), and at a pH of from 8 to 12. The process of the present invention may also include concentrating steps. The silica sol prepared by the method of the present invention has a BET surface area of greater than or equal to 100 m2/g, and contains from 0.05 to 15% by weight of gaunidinium ions, based on the total weight of the silica gel.
Abstract:
A composition for the chemical-mechanical polishing of metal and metal/dielectric structures, containing 7 to 100% by volume of a cationically stablilized silica sol which contains 30% by weight of SiO2 and the SiO2 particles of which have a mean particle size of less than 300 nm, with a pH of from 4 to 10, is distinguished by a TaN removal rate of ≧40 nm per min and an improved barrier layer:metal selectivity of at least 2:1 or greater and a barrier layer:dielectric selectivity of at least 2:1 or above.
Abstract:
In the preparation of m-chloroaromatics by isomerizing corresponding o- and/or p-chloroaromatics in the liquid phase over zeolites, the activity of the zeolites remains at a high level for a particularly long time if the process is carried out in the presence of from 1 to 30 mol % of hydrogen, based on the chloroaromatics used.