Abstract:
A process for the production of 6-alkoxy-5,6-dihydro-4H-pyrans by reaction of Alpha , Beta -unsaturated aldehydes with vinyl ethers. The products are valuable intermediates, for example for the production of glutaraldehyde or substituted glutaraldehydes which may be used for example as tanning agents for leather.
Abstract:
In preparing or reacting alkanolamines, especially at high temperatures, the use of substantially nickel-free alloy steels prevents corrosion and discoloration.
Abstract:
Polyoxyalkylene glycols are prepared by a process in which tetrahydrofuran is polymerized with a total of not more than 95 mol %, based on the amount of tetrahydrofuran used, of one or more comonomers from the group consisting of the cyclic ethers and acetals in the absence of water and in the presence of a monohydric alcohol or of a monocarboxylic acid with the aid of an anhydrous heteropoly acid catalyst, and the polyoxyalkylene glycol is liberated from the resulting polyoxyalkylene glycol monoethers or polyoxyalkylene glycol monoesters by cleavage of the monoether or monoester bond.
Abstract:
A process for the preparation of pourable choline chloride/silica powders by mixing silica with choline chloride and, where appropriate, drying this mixture, wherein spray-dried or fluidized bed-dried silica which has a particle size of from 30 to 250 .mu.m is mixed with an aqueous choline chloride solution which contains from 70 to 80% by weight, based on the solution, of choline chloride and is at from 40.degree. to 80.degree. C., thereafter from 0.05 to 0.4% by weight, based on the mixture, of magnesium stearate or calcium stearate is added and, if appropriate, the resulting mixture is dried.
Abstract:
Polyoxyalkylene glycol monoesters of carboxylic acids are prepared by a process in which tetrahydrofuran or a mixture of tetrahydrofuran with a total of not more than 95 mol %, based on the amount of tetrahydrofuran used, of one or more comonomers from the group consisting of the cyclic ethers and acetals is polymerized in the absence of water and in the presence of a carboxylic acid and of an anhydrous heteropolyacid catalyst.
Abstract:
Polyoxyalkylene glycol monoethers of monohydric alcohols are prepared by a process in which tetrahydrofuran or a mixture of tetrahydrofuran with a total of not more than 95 mol %, based on the amount of tetrahydrofuran used, of one or more comonomers from the group consisting of the cyclic ethers and acetals is polymerised in the absence of water and in the presence of a monohydric alcohol and of an anhydrous heteropoly acid catalyst.
Abstract:
A method of separating heteropoly compounds from mixtures of polyethers, polyesters and/or polyether esters, a protic component and heteropoly compounds, wherein the protic component is removed from the mixture and subsequently separating off the heteropoly compound as a separate phase. The polymer phase which remains is preferably brought into further contact with a solid adsorbent that is capable of adsorbing heteropoly compounds.
Abstract:
Polyoxyalkylene glycol monoethers of monohydric alcohols are prepared by a process in which tetrahydrofuran or a mixture of tetrahydrofuran with a total of not more than 95 mol %, based on the amount of tetrahydrofuran used, of one or more comonomers from the group consisting of the cyclic ethers and acetals is polymerized in the absence of water and in the presence of a monohydric alcohol and of an anhydrous heteropoly acid catalyst.
Abstract:
The average molecular weight of polyoxyalkylene glycols and polyoxyalkylene glycol derivatives is adjusted in the heteropolyacid-catalyzed polymerization of cyclic ethers and/or acetals with ring cleavage in the presence of proton donors by a process in which the amount of the relevant proton donor present in the reaction system is regulated in the course of the reaction by the measurement of the electrical conductivity.
Abstract:
A process for the preparation of polyether glycols by polymerization of tetrahydrofuran or copolymerization of tetrahydrofuran with oxiranes in the presence of from 20 to 500% w/w of a hydrocarbon, based on the weight of tetrahydrofuran used.