摘要:
Bromine containing compounds, such as calcium bromide, sodium bromide and the like, are prepared in high purity and more quickly with less waste by using a process with two bromination stages and often a third step wherein the crude product mixture can be adjusted to meet specific product requirements. In the first bromination stage, the majority, but not all, of a substrate is brominated using a reductive bromination reaction, the remaining unreacted substrate is converted to product in the second stage through another a reductive bromination reaction, although the specific reagents may be different, wherein the addition of bromine and a reducing agent are carefully monitored.
摘要:
The present invention concerns a method for modifying the transfer characteristics of a porous organic or inorganic membrane, in which a) on the said membrane, at least one layer is formed by applying at least one homogeneous solution obtained by mixing one or more rare-earth or alkaline-earth fluoroalkoxides in an anhydrous organic solvent at room temperature and in an inert atmosphere, b) hydrolysis is effected by placing the coating formed at a) in contact with a quantity of water at least equal to the stoichiometric quantity required to hydrolyse the fluoroalkoxides, c) the membrane is rinsed with water to eliminate the soluble salts formed. The membranes thus modified are useful for the regeneration of photographic solutions, in particular black and white developers, or for the separation of organic compounds from aqueous effluents.
摘要:
A method for making zinc bromide from metallic zinc and bromine comprising contacting zinc with bromine dissolved in a reaction solvent containing a metal halide salt. During the practice of this method, the reaction temperature is maintained at less than 60.degree. C. The reaction solvent preferably comprises an alkali, alkaline earth or transition metal halide and the halide salt preferably comprises a chloride or a bromide. One preferred method includes the step of recirculating the zinc bromide product stream back to the reaction vessel. The reaction vessel can comprise either a one stage or a multiple stage reactor. The resulting product stream comprises a high density zinc bromide solution.
摘要:
The present invention relates to a process for the manufacture of potassium nitrate from potassium chloride and nitric acid. According to the invention, potassium chloride and nitric acid are reacted in an aqueous medium at a temperature in the range of between -25.degree. C. to +10.degree. C. From the brine solution obtained after the separation of the resulting potassium nitrate, nitric acid is extracted by an organic solvent solution containing at least one compound selected from the group consisting of ketones having five to ten carbon atoms, straight or cyclic polyethers having molecular weight in the range of 100 to 1000, polyalkylene glycols slightly miscible in water and having molecular weight in the range of 1000 to 3000, and organic esters of phosphoric acid, phosphonic acid and phosphinic acid, or mixtures thereof, in an organic diluent which does not substantially extract hydrochloric acid. The remaining aqueous solution consists of a substantially nitrate-free brine containing hydrochloric acid. The NO.sub.3.sup.- -loaded solvent is washed, the nitric acid as well as the organic solvent being respectively recycled in the process. The process saves appreciable amounts of nitric acid. Optionally, pure hydrochloric acid could be obtained from the nitrate-free brine, by distillation or by solvent extraction using butanols or pentanols as extractants.
摘要:
A method of recovering bromide from bromine-containing smelting ash relates to the field of high efficient separation and recovery of bromine by total wet method. It especially relates to the method of high efficiency separation of bromine salt and lead, zinc recovery of circuit board smelting ash by two-step method. It mainly comprising: sub-molten salt leaching, washing, separate Lead and zinc by adjusting the pH of industrial sulfuric acid, membrane separation and concentration, reuse of water, crude bromine salt recovery by evaporation crystallization of bromine salt. Compared with the traditional baking and recycling process of ash, the invention adopts sodium hydroxide submolten salt leaching technology and membrane separation and concentration technology, to reduce the reaction temperature and tailings discharge greatly, which has a good effect of energy saving and emission reduction.
摘要:
Bromine containing compounds, such as calcium bromide, sodium bromide and the like, are prepared in high purity and more quickly with less waste by using a process with two bromination stages and often a third step wherein the crude product mixture can be adjusted to meet specific product requirements. In the first bromination stage, the majority, but not all, of a substrate is brominated using a reductive bromination reaction, the remaining unreacted substrate is converted to product in the second stage through another a reductive bromination reaction, although the specific reagents may be different, wherein the addition of bromine and a reducing agent are carefully monitored.
摘要:
A process for converting gaseous alkanes to liquid hydrocarbons wherein a gaseous feed containing alkanes is reacted with a dry bromine vapor to form alkyl bromides and hydrobromic acid vapor. The mixture of alkyl bromides and hydrobromic acid are then reacted over a synthetic crystalline alumino-silicate catalyst, such as a ZSM-5 zeolite, at a temperature of from about 150° C. to about 450° C. so as to form higher molecular weight hydrocarbons and hydrobromic acid vapor. Propane and butane which comprise a portion of the products may be recovered or recycled back through the process to form additional C5+ hydrocarbons. Various methods are disclosed to remove the hydrobromic acid vapor from the higher molecular weight hydrocarbons and to generate bromine from the hydrobromic acid for use in the process.