摘要:
Thermoplastics built up from N-(2-ethyl-6-methyl)phenylmaleimide and styrene, it being possible for all or some of the styrene to be replaced by at least one other monomer component.
摘要:
Thermoplastics built up from N-(2-ethyl-6-methyl)phenylmaleimide and styrene, it being possible for all or some of the styrene to be replaced by at least one other monomer component.
摘要:
N-Substituted cyclic imides are obtained by reacting a cyclic acid anhydride with an amine in the presence of a solvent and an acid catalyst at 80.degree. to 200.degree. C. and with removal of the water formed, it being particularly advantageous to carry out this reaction in the presence of a stabilizer and an inert, dipolar aprotic cosolvent, optionally to add an inert organic solvent of low or zero polarity to the reaction mixture present after the reaction, to add a non-aqueous base in an amount of 0.5 to 50% by weight, based on the cyclic anhydride of the formula (II) used, and to separate off the precipitate formed to give a filtrate containing the N-substituted cyclic imide.
摘要:
A process for the preparation of a N-)ortho-alkylphenyl)-imide of the formula ##STR1## in which R.sup.1 to R.sup.9 is defined in the specification which comprises reacting a cyclic anhydride of the formula ##STR2## wherein R.sup.6 to R.sup.9 are difined in the specification with an amine of the formula ##STR3## optionally in the presence of an acid catalyst and optionally in the presence of a solvent which is immiscible or only slightly miscible with water but can form an azeotrope with water, at a temperature between 100.degree. to 200.degree. C. under conditions so that the water formed during the reaction is removed from the reaction mixture without the addition of a polymerization inhibitor or a dipolar solvent. The final products are used as intermediates to prepare heat-stable plastics as well as intermediates to prepare pharmaceutical and agricultural chemicals.
摘要:
The invention relates to the use of the known compound 2,6-dichloro-3-fluoro-benzonitrile as active compound in selectively-herbicidal compositions, and to new preparation processes and new intermediates for the preparation of this compound.
摘要:
Dialkyl dicarbonates are obtained particularly advantageously from halogenoformic esters by reaction with alkalis in the presence of water-immiscible organic solvents and in the presence of a catalyst, if the catalyst used is benzylalkyldimethylammonium halides. The catalyst is then particularly easy to separate off and to recycle from the reaction mixture.
摘要:
In the preparation of m-chloroaromatics by isomerizing corresponding o- and/or p-chloroaromatics in the liquid phase over zeolites, the activity of the zeolites remains at a high level for a particularly long time if the process is carried out in the presence of from 1 to 30 mol % of hydrogen, based on the chloroaromatics used.
摘要:
Aliphatic sulphonic acids can be prepared by reacting n-paraffins with SO.sub.2 and O.sub.2 under UV irradiation with high selectivity even at conversions of up to 12 mol % if an amount of water is added which is appropriate to ensure that after the reaction has commenced and the stationary state has been reached, the sulphoxidation proceeds in homogeneous phase.
摘要:
1,2-Dichlorobenzene can be prepared by reacting 1,2,4-trichlorobenzene in the gas phase with hydrogen. The reaction is carried out at a temperature from the boiling point of the starting material up to about 400.degree. C. and over a platinum-spinel catalyst.
摘要:
Halogenated benzenes are hydrodehalogenated in a particularly advantageous manner and at low temperatures by contacting them at temperatures of between 100.degree. and 250.degree. C. together with hydrogen with a catalyst prepared by application of one or more salts of palladium and/or platinum and, if desired, of copper to an alumina or titanium dioxide support.