摘要:
The present invention relates to a reactor suitable for liquid-phase fluorination and provided, as heating means, with at least one element fixed to the cover so as to be immersed to the bottom of the vessel, characterized in that the parts of said reactor that are liable to be in contact with the reaction medium, other than the heating element, are coated with a tetrafluoroethylene/hexafluoropropylene copolymer and in that the part of the heating element liable to be in contact with the reaction medium is made of silicon carbide.
摘要:
A catalytic process and a device for preparing, in absolute safely, aqueous hydrogen peroxide solutions at high concentration levels directly from hydrogen and oxygen; more particularly, a method whereby hydrogen and oxygen are injected, into the aqueous medium in proportions corresponding to the flammability range of the hydrogen-oxygen mixture, and are present in proportions outside the flammability range in the continuous gas phase. The invention also concerns a device for implementing the method.
摘要:
A variety of plant materials adopted for processing into, e.g., low-calorie vegetable fibers and dietary flours, are bleached by (1) soaking a plant material having a moisture content of up to 50% at a temperature ranging from 20.degree. to 100.degree. C. with an aqueous solution containing an alkaline agent and more than 100 g/l of hydrogen peroxide, and having a pH of at least 8.5, such that the aqueous solution is completely absorbed by the plant material without establishing any liquid phase; (2) heating the soaked plant material at a temperature ranging from 40.degree. to 100.degree. C. for a period of time sufficient to effect the bleaching, and washing the bleached plant material with water and drying it.
摘要:
A process for bleaching a lignocellulosic matter in the form of a mechanical, thermomechanical, chemicomechanical or chemicothermomechanical papermaking pulp, or of wood chips while being converted into one of these pulp types by processing in a machine consisting essentially of two interpenetrating spiral surfaces wound around parallel shafts driven in synchronous rotation in the same direction inside a barrel which encloses them, and determining between upstream and downstream in the direction of forward travel of the matter a series of zones for drawing and braking the matter, which comprises combining a bleaching treatment using a reducing agent and a bleaching treatment using an oxidizing agent, characterized in that, after pretreatment using at least one metal-complexing or sequestering agent, the lignocellulosic matter undergoes a washing operation with an efficiency greater than 96% before undergoing in succession a bleaching treatment using a reducing agent at a pH of between about 8 and 12, a washing operation to remove the reducing agent and a bleaching treatment using an oxidizing agent.
摘要:
The process of making a wet or dry dispersion containing anthraquinone suitable for use in the alkaline digestion of wood comprising cyclizing ortho-benzoylbenzoic acid at a temperature of about 150.degree. to 180.degree. C. and at an absolute pressure between about 5 and 40 millibars in the presence of between about 0.05 to 2 parts by weight of sulfuric acid, having a concentration of at least about 95%, per part by weight of ortho-benzoylbenzoic acid to form a reaction mixture containing anthraquinone, bringing the reaction mixture to a pH of at least about 7 by addition thereto at a temperature between about ambient temperature and 100.degree. C. of an aqueous solution of sodium hydroxide or potassium hydroxide containing between about 10% to 40% hydroxide by weight, and then forming a dispersion thereof and using such dispersion in the alkaline digestion of wood.