1071 results about "Hydrobromic acid" patented technology

An improved continuous process for converting methane, natural gas, or other hydrocarbon feedstocks into one or more higher hydrocarbons or olefins by continuously cycling through the steps of alkane halogenation, product formation (carbon-carbon coupling), product separation, and regeneration of halogen is provided. Preferably, the halogen is continually recovered by reacting hydrobromic acid with air or oxygen. The invention provides an efficient route to aromatic compounds, aliphatic compounds, mixtures of aliphatic and aromatic compounds, olefins, gasoline grade materials, and other useful products.

A process for converting gaseous alkanes to olefins and 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 an X or Y type zeolite, at a temperature of from about 250° C. to about 500° C. so as to form olefins, higher molecular weight hydrocarbons and hydrobromic acid vapor. 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.

The invention discloses a method for preparing tetrapropyl ammonium hydroxide by utilizing bipolar membrane electrodialysis, and the method comprises the following steps of: using a tetrapropyl ammonium bromide aqueous solution as a raw material, processing the tetrapropyl quaternary ammonium salt aqueous solution through a microporous filter, and then enabling the processed tetrapropyl quaternary ammonium salt aqueous solution to enter a material liquid room of a bipolar membrane electrodialyzing device, respectively adding water in an acid room and an alkali room, respectively adding a sodium sulfate solution in pole liquid rooms, controlling the current density, the voltage and the temperature of the bipolar membrane electrodialyzing device to be 150-600 A/M2, 20-300 V and 5-45DEG C respectively, carrying out circulating cooling through chilled saline water in a circulating coil pipe by using an electrodialyzing compartment in a running process, stopping running when the conductivity of the material liquid room is decreased to below 2000 [mu]s/cm, obtaining a tetrapropylammonium hydroxide solution in the alkali room, and recycling a hydrobromic acid solution in the acid room. By using the method, the raw material cost is low; the selectivity is multiple; the purity of the tetrapropyl ammonium hydroxide is high; hydrobromic acid further can be recovered; and the generation of a pollutant in the process is effectively avoided.

The invention discloses a preparation method of 5-bromo-1,3-dichloro-2-fluorobenzene, which comprises the following steps: (1) simultaneously feeding ammonium salt and a sodium nitrite aqueous solution into a tubular reactor for tubular diazotization reaction so as to obtain a diazonium salt intermediate, wherein the ammonium salt is prepared through dissolving 3,5-dichloro-4-fluoroaniline in sulfuric acid; (2) dissolving cuprous bromide in hydrobromic acid, heating to 100-130 DEG C, dropwise adding the diazonium salt intermediate prepared in the step (1) for reaction, and after the complete reaction, performing after-treatment to obtain the 5-bromo-1,3-dichloro-2-fluorobenzene. According to the preparation method, the tubular diazotization reaction technology is adopted to prepare diazonium salt, so that the side reaction including diazonium salt coupling and decomposition and the like can be reduced, the diazotization reaction is enabled to be more stable, and the final yield is improved; in addition, the tubular diazotization reaction technology has a series of advantages of continuity in production, safety, short reaction time, energy saving and the like, and is relatively suitable for industrial production in the future.

A process for converting gaseous alkanes to olefins, higher molecular weight hydrocarbons or mixtures thereof 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 is then reacted over a suitable catalyst at a temperature sufficient to form olefins, higher molecular weight hydrocarbons or mixtures thereof and hydrobromic acid vapor. Various methods are disclosed to remove the hydrobromic acid vapor from the higher molecular weight hydrocarbons, to generate bromine from the hydrobromic acid for use in the process, and to selectively form monobrominated alkanes in the bromination step.

The present invention is process of co-producing sugar and levulic acid solution with lignocellulose material, and belongs to the field of biomass resource utilizing technology. Agricultural and forestry waste as reaction material is dilute acid hydrolyzed in a two-step process at certain temperature and in the presence of 0.01-0.2 mol concentration hydrochloric acid solution, hydroiodic acid solution, sulfuric acid solution or other inorganic acid solution as catalyst to produce both sugar solution and levulic acid solution in the total conversion rate over 20 wt%. The present invention provides one new way for utilizing lignocellulose comprehensively.

The invention relates to the field of graphene materials, in particular to a novel method for preparing a graphene material by reducing graphene oxide (GO). The method is suitable for reducing various graphene-oxide-based powder and thin-film materials. In the method, a graphene oxide product is soaked for 10 seconds-24 hours in a halogenating reagent, such as hydroiodic acid, hydrobromic acid, sulfoxide chloride and the like, in a temperature range from minus 5 DEG C to 140 DEG C, and is taken out and dried, thereby the reduction of the graphene oxide material is completed; and the graphene material obtained after reduction has an excellent electric conduction performance and can maintain the flexibility of thin-film products. The method is simple and is easy to control, can realize the reduction on lots of graphene materials at low temperature with high efficiency and low cost and is beneficial to solving of the problems of environment pollution, high cost and the like in the prior art.

The invention discloses a preparation method for bromoalkane. The preparation method comprises the following steps of: mixing lower alcohol with hydrobromic acid; heating a mixture to a reflow state; enabling the lower alcohol and the hydrobromic acid in the mixture to fully react to obtain a product mixed solution A; distilling the product mixed solution A; condensing the distilled gas to obtain a product mixed solution B; standing the product mixed solution B for layering; taking a lower-layer liquid to obtain a bromoalkane crude product C; rectifying the bromoalkane crude product C; and condensing the rectified gas to obtain liquid bromoalkane. The preparation method has the advantages of simplicity in process and reaction control, no need of catalyst, low production cost, less pollution, favorable quality of products and high purity.

The invention provides a synthesis method of 5-bromo-2-chloro benzoic acid.The method includes the following steps of A, making 2-chlorine benzotrichloride and bromide reagents react under the effect of a catalyst to obtain 2-chloro-5-bromine benzotrichloride, wherein bromide reagents include one or more of bromine, N-bromosuccinimide, dibromohydantoin and hydrobromic acid; B, conducting hydrolysis reaction on 2-chloro-5-bromine benzotrichloride in the step A under the acid condition to obtain 5-bromo-2-chloro benzoic acid.According to the method, 2-chlorine benzotrichloride which is low in price and easy to obtain is adopted as the raw material, operation is easy, intermediates do not need to be purified, 5-bromo-2-chloro benzoic acid is synthesized through a one-pot method, purity is high, yield is high, three-waste emission is little, and production cost is low.It is shown through experiment results that 2-chloro-5-benzoic acid obtained according to the synthesis method has yield larger than 95% and purity of 80-92%.

The invention relates to a preparation method of a bismuth oxyhalide/bismuth oxide visible-light photocatalyst and belongs to the field of visible-light photocatalyst preparation. The method comprises the following steps: dissolving bismuth nitrate in a salpeter solution, adjusting pH with alkali lye, stirring, filtering, washing, drying, calcining at high temperature of 300-600 DEG C for 3-10 hours to prepare yellow bismuth oxide; adding a proper amount of hydrochloric acid, hydrobromic acid or hydroiodic acid with a certain concentration into the prepared bismuth oxide, carrying out an ultrasonic reaction, carrying out centrifugal separation, and drying at constant temperature of 50-100 DEG C for 4-10 hours to obtain the bismuth oxyhalide/bismuth oxide photocatalyst. The method can be carried out at room temperature and at normal pressure. Equipment is simple and easy to operate, can be put into practical use and has a potential application in industrial production. According to the prepared bismuth oxyhalide/bismuth oxide visible-light photocatalyst, the problem of high photo-generated electron and carrier recombination rate is solved effectively, and photocatalytic performance is greatly enhanced.