摘要:
3-Fluoro-4,6-dichlorotoluene can be prepared in a particularly favourable manner by first chlorinating 3-fluorotoluene at low temperature in the presence of a Friedel-Crafts catalyst and a heterocyclic cocatalyst to give a mixture containing 3-fluoro-4-chlorobenzene and 3-fluoro-6-chlorobenzene, and subsequently, without intermediate isolation, further chlorinating this mixture, at higher temperature, after addition of further Friedel-Crafts catalyst and further heterocyclic cocatalyst, to give 3-fluoro-4,6-dichlorotoluene.
摘要:
Impure POCl.sub.3 is purified by distillation in the presence of high-boiling nitrogen compounds from the group consisting of the substituted pyridines and pyrimidines, the open-chain and cyclic aliphatic amines, the open-chain and cyclic amidines, the guanidines and the aromatic amines.
摘要:
Dichlorobenzene having an increased p-content and a greatly reduced m-content is obtained by ring chlorination of benzene or chlorobenzene in the presence of Friedel-Crafts catalysts if the reaction is carried out in the presence of co-catalysts of the formula (I) ##STR1## wherein X represents fluorine, chlorine, bromine, trifluoromethyl or pentafluoroethyl andA represents 2 hydrogen atoms or the group --CH.dbd.CH--CH.dbd.CH--.
摘要:
In the preparation of 2-chloro-4-nitro-alkylbenzene by reaction of 4-nitro-alkylbenzene with elemental chlorine or chlorine-releasing compounds in the presence of a Friedel-Crafts catalyst in the liquid phase, particularly high selectivities in respect of the target compounds chlorinated exclusively in the 2-position are achieved if a dibenzo-condensed sulphur heterocycle of the formula ##STR1## having the meanings given in the description for R.sup.1 to R.sup.8, X and n, is used as co-catalyst.
摘要:
Aromatic hydrocarbons which are monosubstituted by straight-chain or branched C.sub.1 -C.sub.12 -alkyl or by C.sub.3 -C.sub.8 -cycloalkyl can be chlorinated in the presence of Friedel-Crafts Catalysts in liquid phase on the aromatic ring if cyclic benzo-fused imines or benzo[f]-1,4-thiazepines are used as co-catalysts. This makes it possible to obtain a higher proportion of p-isomers.
摘要:
2-Chloroacrylonitrile is prepared in a particularly advantageous and readily industrially practicable manner by chlorinating acrylonitrile and then thermally cleaving the 2,3-diehloropropionitrile formed, by chlorinating acrylonitrile in the presence of a catalyst system comprising dimethylformamide and pyridine and/or pyridine derivatives and subjecting the resulting crude 2,3-dichloropropionitrile to thermal cleavage in the presence of the same catalyst system without the addition of further catalysts.
摘要:
The halogen of a polyhalogenated aromatic compound can be transferred to a monohalogenated or nonhalogenated aromatic compound by reaction in the presence of ruthenium as the element or in the form of compounds and if desired with one or more metal compounds from subgroups I and II of the Periodic Table.
摘要:
Aromatic hydrocarbons monosubstituted by straight-chain or branched C.sub.1 -C.sub.12 -alkyl or by Chd 3-C.sub.8 -cycloalkyl can be chlorinated in the aromatic ring in the liquid phase in the presence of Friedel-Crafts catalysts if cyclic amidines which are oxy-sustituted on the exocyclic N atom are employed as co-catalysts. An increased proportion of the p-isomer is obtained in this reaction.
摘要:
4,4-Dimethyl-1-(p-chlorophenyl)pentan-3-one can be prepared by condensation of pinacolone and p-chlorobenzaldehyde in an alcohol as solvent in the presence of an inorganic base and by subsequent hydrogenation, in which the reaction mixture obtained in the condensation is hydrogenated directly without isolation of the intermediate 4,4-dimethyl-1-(p-chlorophenyl)-1-penten-3-one after the addition of a hydrogenation catalyst at elevated temperature and superatmospheric pressure to give 4,4-dimethyl-1-(p-chlorophenyl)pentan-3-one, after the hydrogenation catalyst has been separated off from the liquid hydrogenation mixture, the alcohol is largely distilled off, and the water content of the bottom product of the distillation is adjusted in such a manner that it separates into an aqueous and an organic phase, and the 4,4-dimethyl-1-(p-chlorophenyl)pentan-3-one is recovered from the organic phase.
摘要:
Aromatic hydrocarbons which are monosubstituted by straight-chain or branched C.sub.1 -C.sub.12 -alkyl or by C.sub.3 -C.sub.8 -cycloalkyl can be chlorinated in the presence of Friedel-Crafts Catalysts in liquid phase on the aromatic ring if 1,6-benzothiazocins are used as co-catalysts. This makes it possible to obtain a higher proportion of p-isomers.