Abstract: A process is provided for the oxidation of p-xylene and methyl p-tolulate with oxygen-containing gases in the Witten-Hercules process for preparing dimetyl terephthalate in at least two sequentially arranged stages and in the presence of a catalyst, wherein the process involves oxidizing p-xylene and methyl p-toluate with oxygen containing gases in at least two sequential stages in the presence of a catalyst, wherein the at least two sequential stages include at least one p-xylene rich stage and at least one methyl p-toluate rich stage, wherein at least one of the following steps (a) and (b) occurs:(a) in the at least one p-xylene rich stage at least a portion of p-xylene present is oxidized in the presence of 5 to 30% by mass of methyl p-toluate, based on a total amount of oxidation mixture in the at least one p-xylene rich stage; or(b) in the methyl p-toluate rich stage at least one of methyl p-toluate or p-toluic acid is oxidized in the presence of 2 to 30% by mass of p-xylene, based on a total amount of m

Abstract: A process for the preparation of terephthalic acid (TA) from pure dimethyl terephthalate (DMT) and/or DMT intermediate product by hydrolysis in a countercurrent reactor at a conversion of greater than 99% and crystallization to give the solid product, characterized in that the sum of the stripping steam (S) and reaction water (W) satisfies the relationshipL.ltoreq.S+W.ltoreq.2L,wherein (L) represents the amount of water necessary to keep the terephthalic acid (TA) produced largely in solution during the reaction and in the bottom of the reactor, and the terephthalic acid produced is crystallized in a crystallization which is free from washing stages.

Abstract: The invention involves spherical particles of magnesium alkoxide and a process for their preparation. Specifically, spherical magnesium alkoxide is produced by spray drying of an alcoholic solution of the corresponding carboxylated magnesium alkoxide and subsequent drying and decarboxylation, characterized in that the solution is sprayed via a two-material nozzle with inner atomization, which is operated in the part-load range at 10 to 30% of its capacity, into an inert accompanying gas which is under a pressure of 1.0 to 1.2 bar, has been preheated to 100.degree.-140.degree. C. and is fed cocurrently, after which the resulting finely divided carboxylated magnesium alkoxide is dried and is decarboxylated. The magnesium alkoxide is used for the preparation of a catalyst for the polymerization of .alpha.-olefins.

Abstract: Stabilized diperoxydicarboxylic acids are prepared in which diperoxydicarboxylic acids are mixed with sodium sulfate produced in the process to yield improved diperoxydicarboxylic acid granules having good chemical stability despite a high impurity content, safe handling, low bulk density and high abrasion resistance.