摘要:
Mixtures comprising organic carbonates, such as carbonates not substituted by fluorine, but especially fluorosubstituted organic carbonates, which are depleted in HF can be obtained from respective mixtures with a higher HF content by a step of stripping such mixture with an inert gas. For example, a reaction mixture comprising fluoroethylene carbonate and HF can be treated in this way. The mixture comprising organic carbonate which is depleted in HF can be distilled to obtain highly purified organic carbonate.
摘要:
Process for the separation of a mixture comprising at least one hydrofluoroalkane and hydrogen fluoride, according to which a hydrofluoroalkane/hydrogen fluoride mixture is reacted with at least one chlorinated or chlorofluorinated precursor of the hydrofluoroalkane. Process for the preparation of a hydrofluoroalkane comprising such a separation, in combination with a catalytic reaction stage. Azeotropic compositions.
摘要:
Process for the separation of a mixture comprising at least one hydrofluoroalkane and hydrogen fluoride, according to which a hydrofluoroalkane/hydrogen fluoride mixture is reacted with at least one chlorinated or chlorofluorinated precursor of the hydrofluoroalkane. Process for the preparation of a hydrofluoroalkane comprising such a separation, in combination with a catalytic reaction stage. Azeotropic compositions.
摘要:
Process for synthesizing a chemical, in particular an agriculturally or pharmaceutically active compound, including: a first step comprising reacting a carboxylic acid halide with a vinyl ether to prepare a halogenated precursor of an alkenone; a second step comprising eliminating hydrogen halide from such precursor to form an alkenone, preferably by thermolysis under specific conditions; and a third step which uses the formed alkenone as a building block to synthesize the chemical. First step may be done in a liquid reaction medium comprising an alkenone or a halogenated alkenone precursor, or in a liquid reaction medium in turbulent state, specifically by creation of gas bubbles of the carboxylic acid halide herein. Second step may include a flash thermolysis, vacuum thermolysis, thermolysis under stripping with inert gas, and/or a thermolysis at a temperature from >90° C. to 120° C. Third step preferably comprises reacting the alkenone with a nitrogen-containing compound.
摘要:
Process for obtaining a hydrofluoroalkane which is purified of organic impurities, according to which the hydrofluoroalkane containing organic impurities is subjected to at least one purification treatment chosen from (a) a treatment with chlorine in the presence of a initiator (b) a reaction with hydrogen fluoride (c) a distillation in which the purified hydrofluoroalkane is removed from the top of the distillation column or from the side (d) an extractive distillation (e) an adsorption onto a solid adsorbent (f) a reaction with a compound containing oxygen, and (g) a reaction with a compound containing oxygen and a gas-phase reaction with a reagent capable of reacting with at least some of the organic impurities, with the exception of a reaction with elemental chlorine.
摘要:
Process for the separation of a mixture comprising at least one hydrofluoroalkane and hydrogen fluoride, according to which a hydrofluoroalkane/hydrogen fluoride mixture is reacted with at least one chlorinated or chlorofluorinated precursor of the hydrofluoroalkane. Process for the preparation of a hydrofluoroalkane comprising such a separation, in combination with a catalytic reaction stage. Azeotropic compositions.
摘要:
Angles and angular displacements of ultrasonic beams are measured by using a probe to transmit the beam to a point on a surface, particularly the surface of material being subjected to non-destructive examination, from which the beam is reflected to a receiving probe which may or may not be the same device as the transmitting probe. The length of the path traversed by the beam is varied in accordance with a relationship determined as a function of the angular displacement of the beam from an axis normal to the surface, and the time taken to traverse the path is detected. The variation in the length of the path may be effected by adjusting the separation of the transmitting probe from the surface while the probe is being angularly adjusted to vary the angular displacement of the beam, a fixed mirror being provided to return the beam by way of the point to the probe. Alternatively an angularly adjustable transmitting probe may direct the beam to the point and a separate probe which is both axially and angularly adjustable arranged to receive the relfected beam. In a third alternative, the transmitting probe directs the beam to the point by way of an adjustable mirror, a fixed mirror being arranged to return the beam by way of the point and the adjustable mirror to the probe.
摘要:
Process for obtaining a hydrofluoroalkane which is purified of organic impurities, according to which the hydrofluoroalkane containing organic impurities is subjected to at least one purification treatment chosen from (a) a treatment with chlorine in the presence of a initiator (b) a reaction with hydrogen fluoride (c) a distillation in which the purified hydrofluoroalkane is removed from the top of the distillation column or from the side (d) an extractive distillation (e) an adsorption onto a solid adsorbent (f) a reaction with a compound containing oxygen, and (g) a reaction with a compound containing oxygen and a gas-phase reaction with a reagent capable of reacting with at least some of the organic impurities, with the exception of a reaction with elemental chlorine.
摘要:
Process for the separation of a mixture comprising at least one hydrofluoroalkane and hydrogen fluoride, according to which a hydrofluoroalkane/hydrogen fluoride mixture is reacted with at least one chlorinated or chlorofluorinated precursor of the hydrofluoroalkane. Process for the preparation of a hydrofluoroalkane comprising such a separation, in combination with a catalytic reaction stage. Azeotropic compositions.