摘要:
A process of dignifying lignocellulosic pulp with oxygen followed by treatment of the delignified pulp with a chelating agent, followed by washing, followed by treatment with hydrogen peroxide at an alkaline pH in the presence of an alkali metal silicate at a temperature greater than 100.degree. C. and a pressure greater than 1.5 times the saturated vapor pressure.
摘要:
A variety of plant materials adopted for processing into, e.g., low-calorie vegetable fibers and dietary flours, are bleached by (1) prebleaching such plant material in a first aqueous solution containing an alkaline agent and hydrogen peroxide, the alkaline agent being present in solution in such amount that the final pH of the resulting suspension is no greater than 9, (2) filtering and washing the suspension produced in step (1) with water, to an effectiveness of at least 50%, (3) bleaching the material obtained after step (2) in a second aqueous solution containing an alkaline agent and hydrogen peroxide, the alkaline agent being present in solution in such amount that the final pH of the resulting suspension is no greater than 8.5, and, characteristically, (4) filtering and washing the suspension produced in step (3) with water.
摘要:
A process for the decomposition of complexes of ortho-benzoyl benzoic acids, hydrogen fluoride, and boron trifluoride, whether or not the ortho-benzoyl benzoic acid is substituted, is disclosed wherein the ortho-benzoyl benzoic acid is obtained separately from the hydrogen fluoride and boron trifluoride. This process is characterized in that the complex is treated with an inert solvent at a temperature of at least 20.degree. C., in a distillation column having at least about 8 theoretical plates whereby the solvent reflux is operated at a rate equal to about 5 to about 40 times the weight of the feed delivery rate of the column.The process of the present invention also makes it possible to recover hydrogen fluoride and boron trifluoride for reuse as catalysts in the synthesis of ortho-benzoyl benzoic acid without causing decomposition of the acid.
摘要:
A process for the preparation of anthraquinone compounds by condensation of phthalic anhydride with a benzene derivative wherein a mixture of hydrofluoric acid and boron trifluoride is utilized as catalyst.
摘要:
The present invention relates to a continuous process for the fluorination of perchloroethylene (PER) in the gas phase in a single stage with hydrofluoric acid (HF) in the presence of a catalyst to give, as major product, pentafluoroethane. The process is characterized in that it is carried out at a temperature of between 280 and 430° C. and with an HF/PER molar ratio of greater than or equal to 20.
摘要:
The present invention relates to a process for the preparation of primary di- and/or triamines of high purity from nitriles which can themselves originate from dimer and/or trimer acids.This process comprises a stage of ammoniation of the acid functional groups and a stage of hydrogenation of the nitrile functional groups to give primary amine functional groups and does not require additional purification stage(s).
摘要:
The present invention relates to a continuous process for the fluorination of perchloroethylene (PER) in the gas phase in a single stage with hydrofluoric acid (HF) in the presence of a catalyst to give, as major product, pentafluoroethane. The process is characterized in that it is carried out at a temperature of between 280 and 430° C. and with an HF/PER molar ratio of greater than or equal to 20.
摘要:
Use is made, for selectively hydrogenating the olefinic double bonds of block copolymers, at least one block of which comprises olefinic double bonds, using a catalyst based on a metal from Group VIII in a medium comprising an organic solvent for the copolymer and an ionic liquid as solvent for the catalyst, of a water-immiscible ionic liquid, preferably an ionic liquid for which the anion is the hexafluorophosphate anion and the cation is the 1-butyl-3-methylimidazolium (bmim+) or 1-ethyl-3-methylimidazolium (emim+) cation.Applied to poly(styrene)-b-poly(butadiene)-b-poly(methyl methacrylate) block copolymers, the poly(butadiene) block of which predominantly possesses a 1,4-microstructure, this process results in copolymers for which the degree of hydrogenation is at least equal to 50% and which exhibit a melting point of greater than 30 °C.
摘要:
The invention concerns a method for making an aqueous solution of hydrogen peroxide. More particularly, it concerns a method for making hydrogen peroxide directly from hydrogen and oxygen, finely dispersed in an aqueous acid medium comprising a catalyst and at least a surfactant. The invention also concerns a device for implementing said method.
摘要:
The invention concerns a supported metal catalyst based on at least one metal selected in the group M consisting of palladium, platinum, ruthenium, rhodium, iridium, holmium, osmium and gold, used for directly making hydrogen peroxide from hydrogen and oxygen. The invention also concerns a method for making said catalyst comprising successively an impregnating step with a solution based on one or several salt(s) of at least one metal of group M on a support, and a reduction step characterised in that at the end of the reduction step, the catalyst is treated with an aqueous acid solution comprising bromine and bromide ions. The catalyst is characterised by metal or crystallised metal aggregates with size ranging between 0.1 and 20 microns and preferably between 0.1 and 10 microns. The supported bimetal catalyst is preferred, for example Pd—Pt, Au—Pt, Pd—Ho and Pd—Au.