Abstract: The present invention relates to a process for preparing phenols by adding an aqueous base to the reaction product from the acid-catalyzed cleavage of alkylaryl hydroperoxides while maintaining a homogeneous phase prior to the work-up of the product.

Abstract: The present invention relates to a process for preparing phenols by adding an aqueous base to the reaction product from the acid-catalyzed cleavage of alkylaryl hydroperoxides while maintaining a homogeneous phase prior to the work-up of the product.

Abstract: The present invention relates to a process for preparing phenols, in which the pH of the reaction product from the acid-catalyzed cleavage of alkylaryl hydroperoxides is set to a value of at least 8 at a temperature of at least 100° C. prior to the work-up of the product. This measure enables the content of undesirable by-products, e.g. hydroxyacetone, in the cleavage product to be significantly reduced. This procedure is particularly advantageously integrated into a process for preparing phenols by: a) acid-catalyzed cleavage of alkylaryl hydroperoxides and b) thermal after-treatment of the cleavage product from step a), with the temperature in step b) being higher than in step a) and is at least 100° C., wherein the adjustment to a pH of at least 8 is carried out after the thermal after-treatment and prior to cooling of the cleavage product.

Abstract: The cleavage product from the acid-catalyzed cleavage of cumene hydroperoxide into phenol and acetone is subjected to thermal after-treatment by a process, which comprises heating the cleavage product in a reactor, wherein the heat supplied for the thermal treatment is the heat generated by at least one exothermic reaction which occurs in the reactor. The exothermic reaction which proceeds in the cleavage product is preferably the cleavage of cumene hydroperoxide.

Abstract: The present invention relates to a process for preparing phenols, in which the pH of the reaction product from the acid-catalyzed cleavage of alkylaryl hydroperoxides is set to a value of at least 8 at a temperature of at least 100° C. prior to the work-up of the product. This measure enables the content of undesirable by-products, e.g. hydroxyacetone, in the cleavage product to be significantly reduced.

Abstract: Phenol and acetone are prepared by a process comprising homogeneously cleaving cumene hydroperoxide in the presence of acid catalyst in a cleavage apparatus comprising at least one reactor having plug flow characteristics thereby producing a cleavage product; recycling some of the cleavage product stream by combining the recycled cleavage product stream with the cumene hydroperoxide-containing feed stream fed to said cleavage apparatus under the condition that the mass flow ratio of the recycled partial cleavage product stream to the cumene hydroperoxide-containing feed stream sent to the cleavage reactor is less than 10.

Abstract: A process for preparing crude dimethyl terephthalate, comprises oxidizing a mixture comprising para-xylene and methyl para-toluate, esterifying the oxidized mixture with methanol, separating the resulting crude ester into fractions. By separating the crude ester with a distillation column containing structured packing and using a lower bottom temperature, product yield is increased, and the process is made more economical.

Abstract: A process for purifying a crude ester containing dimethyl terephthalate, includes flash distilling a mixture including para-xylene and methyl para-toluate, and separating the crude ester into fractions. By separating the crude ester with a distillation column containing structured packing and using a lower bottom temperature, product yield is increased, and the process is made more economical.

Abstract: A process for preparing crude dimethyl terephthalate, comprises oxidizing a mixture comprising para-xylene and methyl para-toluate, esterifying the oxidized mixture with methanol, separating the resulting crude ester into fractions. By separating the crude ester with a distillation column containing structured packing and using a lower bottom temperature, product yield is increased, and the process is made more economical.

Abstract: Diols of 3 to 10 carbon atoms are catalytically dehydrogenated over a catalyst containing copper and chromium in a first stage in which the diols are passed in the liquid phase over the catalyst, and subsequently the reaction product obtained is passed in the gas phase over the catalyst.