摘要:
A process for preparing unsymmetric biphenols, comprising: a) adding a first substituted phenol to the reaction mixture; b) adding a second substituted phenol having different substitution than the first phenol to the reaction mixture; c) adding selenium dioxide to the reaction mixture; d) adding a solvent; and e) heating the reaction mixture such that the first substituted phenol and the second phenol having different substitution are converted to an unsymmetric biphenol.
摘要:
The invention relates to processes for preparing aldehydes by hydroformylation of alkenes, in which an alkene-containing feed mixture is subjected to a primary hydroformylation with synthesis gas in the presence of a homogeneous catalyst system, the primary hydroformylation being effected in a primary reaction zone from which a cycle gas containing at least some of the products and unconverted reactants of the primary hydroformylation are drawn off continuously and partly condensed, with recycling of uncondensed components of the cycle gas into the primary reaction zone, and with distillative separation of condensed components of the cycle gas in an aldehyde removal stage to give an aldehyde-rich mixture and a low-aldehyde mixture. The problem that it addresses is that of developing the process such that it achieves high conversions and affords aldehyde in good product quality even in the case of a deteriorating raw material position. More particularly, a solution is to be found for making legacy oxo process plants capable of utilizing lower-value raw material sources. This problem is solved by separating the low-aldehyde mixture into a retentate and a permeate by means of a membrane separation unit in such a way that alkenes present in the low-aldehyde mixture become enriched in the permeate, while alkanes present in the low-aldehyde mixture become enriched in the retentate. The alkene-rich permeate is then transferred into a secondary reaction zone and subjected to a secondary hydroformylation therein with synthesis gas in the presence of an SILP catalyst system. The reaction product obtained from the secondary hydroformylation is recycled into the aldehyde removal stage.
摘要:
The invention relates to a mixture of bisphosphites, to a process for preparation thereof, and to the reaction thereof with metals to give mixtures comprising complexes of the constitutionally isomeric bisphosphites and the metal, and to the use thereof as a catalytically active composition in hydroformylation reactions, and also to the hydroformylation reaction itself.
摘要:
A process for preparing a 2,2′-selenobiaryl ether or a 4,4′-selenobiaryl ether, proceeds by a) adding a first phenol to the reaction mixture, b) adding a second phenol to the reaction mixture, c) adding selenium dioxide to the reaction mixture, d) adding a base having a pKb in the range from 8 to 11 to the reaction mixture, and e) adjusting the reaction temperature of the reaction mixture such that the first phenol and the second phenol are converted to said 2,2′-selenobiaryl ether or said 4,4′-selenobiaryl ether.
摘要:
Electrochemical process for coupling two phenols of different oxidation potential, and novel biphenols which can be prepared by this electrochemical coupling.
摘要:
The invention relates to an electrochemical method for the selective coupling of a phenol to a naphthol which differ in their oxidation potential. The invention also relates to compounds which can be produced by electrochemical coupling.
摘要:
A process for preparing a 2,2′-biphenol, proceeds by a) adding a first phenol to a reaction mixture, b) adding a second phenol to the reaction mixture, c) adding selenium dioxide to the reaction mixture, d) adding an acid having a pKa in the range from 0.0 to 5.0 to the reaction mixture, and e) heating the reaction mixture such that the first phenol and the second phenol are converted to said 2,2′-biphenol.
摘要:
A process for photocatalytic acceptor-free dehydrogenation of alkanes and alcohols, in which an alkane or an alcohol is irradiated in the presence of a rhodium complex containing organic phosphorus(III) compounds as ligands as a catalyst, and in the presence of at least one Lewis base is provided.