Abstract:
The invention relates to a process for hydroxylating phenolic substrates such as phenols or phenol ethers. The process comprises reacting the phenolic substrate and hydrogen peroxide in the presence of a catalyst in a reaction mixture; and simultaneously removing water from the reaction mixture. The process improves the reaction rate, yield, and product selectivities.
Abstract:
Phenol is formed by reaction of oxidant and benzene over a solid catalyst such as Pd on TS-1, the reaction being carried out in carbon dioxide solvent at conditions effective to provide a dense phase reaction mixture.
Abstract:
A process is described for preparing hydroxylated aromatic compounds by means of the direct oxidation of an aromatic substrate with hydrogen peroxide in a triphasic reaction system, in the presence of a TS-1 zeolitic catalyst.
Abstract:
A process for hydroxylating benzene under catalytic distillation conditions to produce hydroxylated products such as phenol is provided. The process provides for direct hydroxylation of liquid phase benzene with an oxidant and a zeolite catalyst under conditions effective to prevent coke formation on the catalyst.
Abstract:
A process for hydroxylating an aromatic compound comprises the steps of: a) contacting an aromatic compound with a catalyst having an average concentration of alpha -sites of at least about 1.10 per gram of catalyst, the catalyst having alpha -oxygen loaded thereon, whereby a hydroxylated derivative of the aromatic compound is produced; and b) regenerating the catalyst when the concentration of alpha -sites falls below a predetermined value. The predetermined value will depend on the process design, but can suitably be about 1.10 per gram of catalyst or higher. Another embodiment of the process comprises: a) contacting an aromatic compound with a catalyst having an average concentration of alpha -sites of at least about 1.10 per gram of catalyst, the catalyst having alpha -oxygen loaded thereon, whereby a hydroxylated derivative of the aromatic compound is produced; and b) reloading the catalyst with alpha -oxygen by contacting the catalyst with a free oxidant activator. The progress of the reloading of the catalyst can be determined by: a) passing an input gas stream over the catalyst, the input gas stream comprising an inert gas; b) collecting an output gas stream that has passed over the catalyst; c) introducing a plurality of nitrous oxide impulses into the input gas stream, each impulse being separated by a period in which the input gas stream contains no nitrous oxide; d) measuring the concentrations of nitrous oxide and nitrogen gas in the output gas stream after an impulse of nitrous oxide is introduced; and e) comparing the concentrations of nitrogen gas and nitrous oxide in the output gas stream.
Abstract:
The present invention discloses a photocatalytic process for oxidation of aromatic hydrocarbons using noble metal deposited vanadium-titania composite catalyst with high selectivity and yield of corresponding oxidized product at ambient conditions.
Abstract:
La presente invención se refiere a un procedimiento para la oxidación catalítica de benceno hasta fenol donde el agente oxidante es peróxido de hidrógeno y el medio de reacción es una mezcla de acetonitrilo y agua, donde la oxidación catalítica del benceno se produce mediante un sistema catalítico basado en compuestos de cobre de fórmula Tp x Cu(NCCH 3 ). Mediante este procedimiento, se han alcanzado conversiones de los hidrocarburos de partida cercanas al 39% con selectividades en fenol superiores al 92%, en procesos que tienen lugar a 60°C con tiempos de reacción de 2-4 h.
Abstract:
Industrial applications of nitrous oxide, e.g. the hydroxylation of benzene to phenol, require large quantities of nitrous oxide having a very low impurity content.According to the invention, nitrous oxide which is obtained by reaction of ammonia with nitric acid can be used for the hydroxylation of aromatics, the use of nitrous oxide from the reaction of ammonia with nitric acid in particular being economically advantageous because all starting materials are available in sufficient quantity and at a favorable price.