Abstract: The present invention relates to the preparation of nitrobenzoic acids by oxidizing particular nitrotoluenes, nitrobenzyl alcohols, esters and/or ethers in the presence of nitric acid at elevated temperature and elevated pressure. It has been found that the particular nitrotoluenes, nitrobenzyl alcohols, esters and/or ethers may be oxidized particularly reliably and in high yields using nitric acid to the benzoic acid derivatives when they are metered into the nitric acid.

Abstract: The present invention relates to the preparation of nitrobenzoic acids by oxidizing particular nitrotoluenes, nitrobenzyl alcohols, esters and/or ethers in the presence of nitric acid at elevated temperature and elevated pressure. It has been found that the particular nitrotoluenes, nitrobenzyl alcohols, esters and/or ethers may be oxidized particularly reliably and in high yields using nitric acid to the benzoic acid derivatives when they are metered into the nitric acid.

Abstract: The present invention relates to the preparation of nitrobenzoic acids by oxidizing particular nitrotoluenes, nitrobenzyl alcohols, esters and/or ethers in the presence of nitric acid at elevated temperature and elevated pressure. It has been found that the particular nitrotoluenes, nitrobenzyl alcohols, esters and/or ethers may be oxidized particularly reliably and in high yields using nitric acid to the benzoic acid derivatives when they are metered into the nitric acid.

Abstract: The invention relates to a process for the preparation of carbonates having a six-membered ring, of the formula ##STR1## by transesterification of 1,3-propanediol compounds with carbonic acid esters and subsequent distillative depolymerization of the oligo- or polycarbonate initially formed, one or more catalysts from the group consisting of compounds of Sn, Ti or Zr being employed both for the transesterification and for the depolymerization and, if appropriate, the distillation residue is at least partly recycled into the transesterification. Such carbonates having a six-membered ring can furthermore be stabilized against undesirable polymerization by addition of small amounts of acids of sulfur or phosphorus or esters or salts thereof.

Abstract: Hydroxypivalic acid is obtained from aqueous solutions by removal of the water by azeotropic distillation and subsequent crystallization from a solvent mixture which is composed of a polar and a non-polar component. The distillation is carried out under reduced pressure and at a maximum bottom temperature of 90.degree. C., until a residual water content of at least 0.1% of the total weight of the resulting solution is achieved.

Abstract: Hydroxypivalic acid can be prepared by oxidation of hydroxypivalaldehyde with hydrogen peroxide by metering the hydrogen peroxide, as the oxidizing agent, into an aqueous hydroxypivalaldehyde reservoir in the temperature range from 60.degree. to 80.degree. C. such that a hydrogen peroxide concentration of 4% by weight, based on the total weight of the reaction mixture, is not exceeded, and ending the addition of hydrogen peroxide as soon as the concentration of hydroxypivalaldehyde in the reaction mixture falls below 1% by weight.

Abstract: o-Hydroxy-benzaldehydes can be obtained by oxidation of the o-cresols, on which they are based, with oxygen in the presence of substances having a base reaction in a solvent if chelate complexes of iron, manganese or a mixuture of both with polyaza-macrocycles as chelating agents are employed as catalysts. Copper or a copper compound is advantageously added as a co-catalyst.

Abstract: To facilitate assembly of an automotive alternator, the alternator housing (11) is separated into two axially split half-shells (11a, 11b), the dividing line (11c) preferably passing through the axis of the shaft (18) of the alternator. The alternator assembly is made by providing a subassembly including the shaft, electromagnetic rotor structure, bearings, and a disk element in which rectifier diodes are seated and which can also support holders in engagement with the slip rings and the voltage regulator. The stator is slipped around the subassembly, a fan wheel and pulley can be attached to the subassembly which is then placed into one half-shell. The bearings and the concentric elements are positioned in alignment by seats formed in the half-shell, and the axial alignment can be accurately checked, and if the alignment is found proper, the second half-shell is assembled thereover.

Abstract: A support carrier of electrically conductive material is secured to the shaft of the machine. A plurality of slip rings are secured to the support carrier, one of the slip rings being fixed thereto directly so that the support carrier will form one terminal of the electrical connection for the slip rings, and an insulating layer is placed over the support carrier over which the other slip ring is located. Preferably, the support carrier is formed with a flange which is notched, one of the notches serving to form an electrical connection for the wire of the field of the machine for connection to the slip ring which is directly secured to the support carrier, the other notch in the flange being wider and gripping around the insulation of the other wire of the field, the wire of the field then being connected to the slip ring which is carried on the insulation. That slip ring, preferably, is also formed with an external flange to which its connecting wire can be secured, for example by soldering.