摘要:
Liquid epoxy resin hardeners are mixtures of 2-ethyl-4-methylimidazole, ethyldimethylimidazole and/or diethylmethylimidazole isomers which can also contain other alkylimidazoles, and can be produced by distillation of the products obtained in the dehydrogenation of 2-ethyl-4-methylimidazoline.
摘要:
1-Alkyl-5-nitroimidazoles are prepared by reacting a 5-nitroimidazole with an alkylating agent in the presence of an aliphatic carboxylic acid. The products are intermediates for the production of dyes, textiles auxiliaries and insecticides.
摘要:
Imidazole-4,5-dicarboxylic acid is prepared by a process in which imidazole is reacted with formaldehyde, and the reaction mixture is treated with nitric acid.
摘要:
New imidazole-copper complex compounds having a good fungicidal action, fungicides containing these compounds as active ingredients, processes for their manufacture, and their use for combating fungi.
摘要:
1-Hydroxymethylimidazoles which are unsubstituted or alkyl-substituted in the 2-position, their manufacture and their use as chemical intermediates, e.g. for other imidazole derivatives or for the drug cimetidine.
摘要:
A process for the manufacture of 5-hydroxymethylimidazoles by reaction of an imidazole with formaldehyde or an oligomer of formaldehyde in aqueous hydrochloric acid solution containing from 5 to 18% by weight of hydrogen chloride, at from 80.degree. to 160.degree. C., if desired in a closed system under pressure, followed by isolation in the form of its hydrochloride of the 5-hydroxymethylimidazole obtained.
摘要:
1-Hydroxymethylimidazoles which are unsubstituted or alkyl-substituted in the 2-position, their manufacture and their use as chemical intermediates, e.g. for other imidazole derivatives or for the drug cimetidine.
摘要:
In a process for the continuous preparation of alkyl esters of (meth)acrylic acid by reacting (meth)acrylic acid with alkanols having from 1 to 8 carbon atoms in a homogeneous, liquid, solvent-free phase at elevated temperature and in the presence of an acid esterification catalyst, in which the (meth)acrylic acid, the alkanol and the acid catalyst are fed to a reaction zone, the water formed is removed by rectification during a residence time as constituent of a mixture comprising starting alkanol in a rectification unit (III) superposed on the reaction zone, the distillate obtained is separated into an organic phase comprising alkanol and an aqueous phase comprising water, the organic phase is essentially completely returned to the rectification unit (III), the reaction mixture is discharged from the reaction zone and conveyed into a distillative separation zone comprising further rectification units and in the latter the alkyl (meth)acrylate formed is separated off.a) (Meth)acrylic acid and alkanol are reacted in a molar ratio of from 1:0.75 to 1:2, b) part of the aqueous phase obtained at the top of the rectification unit (III) is returned to the rectification unit, c) the reaction mixture discharged from the reaction zone is fed to a further rectification unit (I) and in this the reaction mixture is separated into a product (II) comprising the catalyst and a product (I) comprising the alkyl ester of (meth)acrylic acid, remaining alkanol and remaining (meth)acrylic acid, and d) the product (I) is fed to a further rectification unit (II) and in this the alkyl ester of (meth)acrylic acid is separated from the remaining alkanol and from the remaining (meth)acrylic acid and the remaining alkanol and the remaining (meth)acrylic acid are returned to the reaction zone.
摘要:
A process for preparing substituted imidazoles of the formula I ##STR1## R.sup.1, R.sup.2 and R.sup.3 are identical or different and are each hydrogen, halogen, NO.sub.2, CN or a C.sub.1 -C.sub.20 -hydrocarbon radical which is unsubstituted or substituted by one or more halogens or R.sup.1 and R.sup.2 together are members of a 3- to 20-membered hydrocarbon ring which is unsubstituted or substituted by one or more halogens and/or C.sub.1 -C.sub.8 -alkyl groups and which may contain 1, 2 or 3 heteroatoms from the group consisting of nitrogen, oxygen and sulfur, andR.sup.4 is a C.sub.1 -C.sub.20 -hydrocarbon radical which is unsubstituted or substituted by one or more halogens,comprises using an aqueous phase of the imidazoles of the formula II ##STR2## where R.sup.1, R.sup.2 and R.sup.3 are as defined above with compounds of the formula IIIR.sup.4 --O--R.sup.5 IIIwhereR.sup.4 is as defined above andR.sup.5 is hydrogen or R.sup.4, it being possible in the latter case for the two R.sup.4 substituents to be identical or different,and reacting it at from 200.degree. to 550.degree. C. in the presence of a catalyst comprising oxides and/or phosphates of one or more metals of the 2nd, 3rd and 4th main group and the 4th subgroup of the Periodic Table in the presence or absence of phosphoric acid and/or phosphoric esters.
摘要:
N-substituted-pyrazoles of the formula ##STR1## wherein R.sup.1 is C.sub.1 -C.sub.12 -alkyl or C.sub.7 -C.sub.20 -alkyl, and R.sup.2, R.sup.3 and R.sup.4 independently denote hydrogen, C.sub.1 -C.sub.12 -alkyl, phenyl, C.sub.7 -C.sub.20 -alkylphenyl and C.sub.7 -C.sub.20 -phenylalkyl, are prepared by reacting a pyrazole of the formula ##STR2## wherein R.sup.2, R.sup.3 and R.sup.4 have the meanings above, with an alcohol or ether of the formulaR.sup.1 --O--R.sup.5 III,wherein R.sup.5 is hydrogen or R.sup.1, at a temperature of from 200.degree. to 550.degree. C. and a pressure of from 0.001 to 50 bar in the presence of a heterogeneous catalyst, preferably one which contains acid centers such as the oxides of aluminum, silicon, titanium and/or zirconium, optionally doped with phosphoric acid.