Abstract: A process for the preparation of 2-alkyl-6-methyl-N(1'-methoxy-2'-propyl)-aniline by catalytic reductive alkylation wherein at least one mole equivalent of methoxyacetone is reacted with one mole equivalent of 2-alkyl-6-methyl-aniline in a liquid medium without an additional solvent, in the presence of a platinized carbon catalyst and hydrogen and in the presence of an acid cocatalyst under a hydrogen pressure of between 2.times.10.sup.5 and 1.times.10.sup.6 Pa at a temperature between 20.degree. and 80.degree. C., characterized in that the reaction mixture contains water from the beginning of the reaction and after the hydrogenation, base is added, the reaction mixture is filtered to separate the catalyst and the title compound recovered from the filtrate. The process is particularly useful for the preparation of N-substituted chloracetanilide herbicides.

Abstract: In the process for the purification of diemthyl terephthalate (DMT) by recrystallization from methanolic solution, the mother liquor containing the impurities, substantially the isomers DMI, DMO and aldehydes, is separated off and passed to a workup tank. The moist crystals are dried by melting with the evaporation of methanol. The mother liquor is then separated off by filtration, and the moist crystals obtained from the separation are washed before melting. The washing liquid is recycled together with a portion of the separated mother liquor into the recrystallization tank.

Abstract: The invention relates to a process for separating dimethyl isophthalate (DMI) and dimethyl orthophthalate (DMO) and other by-products from their mixture with dimethyl terephthalate (DMT), formed in the oxidation of p-xylene followed by esterification with methanol, by crystallization from the melt.Initially, the esterification product is here distilled once or several times. The DMT-rich fraction obtained is then subjected wholly or partially to one or several crystallizations from the melt, and the DMI-DMO fraction thus obtained is at least partially removed from the system. As an alternative, the DMT-rich fraction is first recrystallized from methanol, the methanol is then evaporated from the mother liquor and the remaining residue is subjected to one or several crystallizations from the melt. The DMI-DMO fraction thus obtained is again at least partially removed from the system.

Abstract: A new improved process for producing pyridinaldehydes and hydrazone derivatives thereof, for example, pyridinaldehyde-phenylhydrazones, is described. This comprises reacting an aminomethylpyridine with an aldehyde or a ketone to give a compound of the formula ##STR1## isomerizing the compound (III), in the presence of suitable catalysts, to a compound of the formula ##STR2## and converting the compound (V), in the presence of an acid and optionally in the presence of a hydrazine, into a pyridinaldehyde or a pyridinaldehyde-hydrazone. It is possible to produce by the process according to the invention pyridinaldehydes and pyridinaldehyde-hydrazones in a simple manner, under mild ecologically favorable conditions and in good to very good yields.

Abstract: An improved process for producing pyridinaldehydes and hydrazone derivatives thereof, for example, pyridinaldehyde-phenylhydrazones, is described. This comprises reacting a aminomethylpyridine with an aldehyde or a ketone to give a compound of the formula ##STR1## isomerizing the compound (III), in the presence of suitable catalysts, to a compound of the formula ##STR2## and converting the compound (V), in the presence of an acid and optionally in the presence of a hydrazine, into a pyridinaldehyde or a pyridinaldehyde-hydrazone. It is possible to produce by the process according to the invention pyridinaldehydes and pyridinaldehyde-hydrazones in a simple manner, under mild ecologically favorable conditions and in good to very good yields.

Abstract: A process for producing benzotriazoles of the formula I ##STR1## wherein R.sub.1 is hydrogen or chlorine,R.sub.2 is hydrogen, chlorine, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, C.sub.2 -C.sub.9 alkoxycarbonyl, carboxyl or sulfo,R.sub.3 is C.sub.1 -C.sub.12 alkyl, C.sub.1 -C.sub.4 alkoxy, phenyl, (C.sub.1 -C.sub.8 alkyl)-phenyl, C.sub.5 -C.sub.6 cycloalkyl, C.sub.2 -C.sub.9 alkoxycarbonyl, chlorine, carboxyethyl or C.sub.7 -C.sub.9 phenylalkyl,R.sub.4 is hydrogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, chlorine or hydroxyl, andR.sub.5 is hydrogen, C.sub.1 -C.sub.12 alkyl, chlorine, C.sub.5 -C.sub.6 cycloalkyl or C.sub.7 -C.sub.9 phenylalkyl,which process comprises treating a benzotriazole-N-oxide of the formula II ##STR2## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 have the above meanings, at a temperature of 20.degree.-150.degree. C., with an amine; or treating an o-nitroazobenzene of the formula III ##STR3## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.