摘要:
Processes comprising: (a) enantioselectively hydrogenating a staffing material comprising a component selected from geraniol, nerol and mixtures thereof to form optically active citronellol; (b) converting the optically active citronellol to optically active citronellal; (c) cyclizing the optically active citronellal to form a mixture comprising optically active isopulegol; and (d) subjecting the mixture to further processing comprising: (i) separating the optically active isopulegol from the mixture and hydrogenating the separated optically active isopulegol to form optically active menthol; or (ii) hydrogenating the optically active isopulegol in the mixture to form optically active menthol and separating the optically active menthol from the mixture.
摘要:
The present invention relates to diarylphenoxyaluminum compounds which are obtainable by reacting a bis(diarylphenol) ligand of the formula (I) with an alkylaluminum compound and/or a complex aluminum hydride. The invention moreover relates to the use of such diarylphenoxyaluminum compounds as catalysts.Moreover, the invention relates to a method of producing isopulegol by cyclization of citronellal in the presence of diarylphenoxyaluminum compounds as catalysts.The invention also relates to a method of producing menthol by cyclization of citronellal in the presence of diarylphenoxyaluminum compounds as catalysts and subsequent hydrogenation.
摘要:
The present invention relates to a process for preparing optically active aldehydes or ketones which have from 3 to 25 carbon atoms and at least one racemizable stereocenter by catalytic dehydrogenation of the corresponding optically active primary or secondary alcohols in the gas phase in the presence of a catalyst.
摘要:
The present invention relates to diarylphenoxyaluminum compounds which are obtainable by reacting a bis(diarylphenol) ligand of the formula (I) with an alkylaluminum compound and/or a complex aluminum hydride.The invention moreover relates to the use of such diarylphenoxyaluminum compounds as catalysts.Moreover, the invention relates to a method of producing isopulegol by cyclization of citronellal in the presence of diarylphenoxyaluminum compounds as catalysts.The invention also relates to a method of producing menthol by cyclization of citronellal in the presence of diarylphenoxyaluminum compounds as catalysts and subsequent hydrogenation.
摘要:
The invention relates to a process for preparing cyclohexanedicarboxylic acids or derivatives thereof, such as esters and/or anhydrides, encompassing the reaction of diene/maleic acid anhydride mixtures, in particular of butadiene/maleic acid anhydride mixtures or of mixtures of maleic acid anhydrides and C5-dienes to give alkyl-substituted or unsubstituted cyclohexenedicarboxylic acid anhydrides in the condensed phase, ester formation, and then hydrogenation to give the corresponding cyclohexanedicarboxylic acid derivative, and also to the use of the cyclohexanedicarboxylic acids or derivatives thereof prepared according to the invention as plasticizers for plastics.
摘要:
The present invention relates to a process for preparing optically active aldehydes or ketones which have from 3 to 25 carbon atoms and at least one racemizable stereocenter by catalytic dehydrogenation of the corresponding optically active primary or secondary alcohols in the gas phase in the presence of a catalyst.
摘要:
A process for the preparation of imidazo[1,2-a]-5,6,7,8-tetra hydropyridin-8-ones by reaction of γ-butyrolactones with imidazols, novel imidazo[1,2-a]-5,6,7,8-tetrahydropyridin-8-ones, and their use for the preparation of imidazo[1,2-a]pyridines are described.
摘要:
Aromatic hydrocarbons are nitrated by a process in which the aromatic hydrocarbon is reacted in the liquid phase with an oxide of nitrogen selected from NO, N2O3, NO2 and N2O4 and with an oxygen-containing gas stream in the presence of a heterogeneous oxidic catalyst, wherein at least 0.1 mol %, based on the aromatic hydrocarbon, of water is present at the beginning of the reaction.
摘要翻译:通过芳烃在液相中与选自NO,N 2 O 3,NO 2和N 2 O 4的氮氧化物和含有异质氧化催化剂的含氧气流反应的方法进行硝化,其中 在反应开始时,存在至少0.1mol%的基于芳烃的水。
摘要:
A process for preparing acetals of the formula I where a) the Rs are, independently of one another, a C1-C20-alkyl or C3-C20-alkenyl radical, or b) the two R radicals together form the members of an unsubstituted or C1-C10-alkyl-substituted 5- to 7-membered cyclic acetal, by reacting 3-methyl-2-butenal in the presence of sulfamic acid, of a N-(C1-C8-alkyl)sulfamic acid or of a N,N-di(C1-C8-alkyl)sulfamic acid as catalyst with: an alcohol of the formula R—OH (IIa), or an orthoester of the formula HC—(OR)3 (III) or a mixture of an alcohol of the formula (IIa) and an orthoester of the formula (III), or an alcohol of the formula HO—(CH2)m—OH (IIb), where m is a number from 2 to 4, and (CH2)m group in the alcohol IIb may be substituted by a C1-C10-alkyl group.
摘要:
A process for the preparation of 2,4-dimethyl-3,5-bisalkoxycarbonylpyrrole is described, in which an acetoacetic alkyl ester is nitrosated to give the 2-nitrosoacetoacetic alkyl ester, the nitroso compound is reduced using hydrogen in the presence of a noble metal catalyst to give the amine, and the resulting amino compound is condensed without isolation in the presence of the corresponding non-nitrosated acetoacetic alkyl ester to give the 2,4-dimethyl-3,5-bisalkoxycarbonylpyrrole. The process makes it possible to work under conditions which are milder than in the prior art and to avoid the formation of by-products.