The invention provides a method for preparing silicon tetrafluoride. The method comprises the following step of: reacting liquid hydrogen fluoride with a Si source under the action of concentrated sulfuric acid to obtain the silicon tetrafluoride. The liquid hydrogen fluoride is taken as a raw material, water content in the raw material is reduced, and the influence of the water content on the generated silicon tetrafluoride is reduced, so that the purity of the silicon tetrafluoride is improved. In addition, compared with hydrogen fluoride gas, the liquid hydrogen fluoride serving as the raw material has the advantages that: the loss of hydrogen fluoride can be reduced, the content of a hydrogen fluoride impurity in the generated silicon tetrafluoride is reduced, and the purity of the silicon tetrafluoride is improved. Furthermore, the Si source is mixed with the concentrated sulfuric acid uniformly, and the liquid hydrogen fluoride is added into the mixture for reaction, so that the volatilization of the hydrogen fluoride can be reduced, the utilization rate of the hydrogen fluoride can be improved and the purity of the obtained silicon tetrafluoride can be improved. Experiments show that: the silicon tetrafluoride prepared by the method has the purity of over 96 weight percent.

Method for preparing silicon tetrafluoride

PROBLEM TO BE SOLVED: To provide the technology for producing CO x by using the saccharides largely included in the biomass resource under relatively mild conditions, the technology for selectively producing prescribed organic acid or its alkali salt from saccharides, further the technology for producing organic acid or its alkali salt from the biomass resource other than saccharide. SOLUTION: Saccharide and alkali metal hydroxide are allowed to react with each other at 150°C to 450°C under the anoxic atmosphere to simultaneously produce organic acid or its alkali metal salt and hydrogen. The molar ratio of saccharide to the alkali metal hydroxide is set to 1 mole of the carbon included in the saccharide to 0.5 to 10 moles. Formic acid, acetic acid, glycolic acid, lactic acid, dicarboxylic acid or their alkali metal salts can be selectively produced by controlling the heating temperature and the like. In addition, organic acid or its alkali metal salts also can be obtained when ligrin is used instead of saccharide. COPYRIGHT: (C)2007,JPO&INPIT

Method and equipment for production of organic acid

Disclosed is a process for producing a fluoride gas that can produces fluoride gases such as BF3, SiF4, GeF4, PF5 or AsF5 at a reduced production cost in a simple manner. The process is characterized in that a compound containing an atom, which, together with a fluorine atom, can form a polyatomic ion, is added to a hydrogen fluoride solution to produce the polyatomic ion in a hydrogen fluoride solution and to evolve a fluoride gas comprising the fluorine atom and the atom that, together with the fluorine atom, can form a polyatomic ion.

Process for producing fluoride gas

PROBLEM TO BE SOLVED: To obtain an organic acid suitable as a substrate for hydrogen production by a bioreactor and to provide a method for producing an organic acid, with which the organic acid, especially formic acid is obtained from a biomass in high selectivity and in a high yield and which has a low burden to the environment. SOLUTION: The method for producing an organic acid comprises at least a pressurized hot water treatment by using pressurized hot water in the presence of an oxidizing agent, treating a biomass and forming an organic acid from the biomass. The oxidizing agent is preferably hydrogen peroxide, the concentration of hydrogen peroxide is ≥6vol.% and pressurized hot water is either supercritical water or subcritical water. The organic acid is preferably formic acid. The organic acid is produced by the method for producing the organic acid. COPYRIGHT: (C)2007,JPO&INPIT

Organic acid and method for producing the same

The invention discloses a method for closed-loop production of silicon tetrafluoride by utilizing sulfuric acid and quartz sand The method comprises the following steps: proportionally adding 95%-98% sulfuric acid and fluoride continuously to a hydrogen fluoride reaction converter to react at 280-360 DEG C to generate hydrogen fluoride gas; premixing 65%-95% sulfuric acid with silica powder; adding the mixture to a reactor, stirring, and adding liquid hydrogen fluoride to react at 50-100 DEG C for 10-1000 minutes to generate silicon tetrafluoride gas; and pouring dilute sulfuric acid into a sulfur trioxide absorption tower, then gradually adding sulfur trioxide to react with water in the dilute sulfuric acid to synthesize sulfuric acid for later use, and recycling the hydrogen fluoride generated through the sulfuric acid reaction in the converter to form closed-loop production By using sulfur trioxide to balance water, the invention greatly improves the stability of a system; closed-loop production is formed through concentration of dilute sulfuric acid and cyclic reuse of residual hydrogen fluoride liquid and silica residue slurry, thus eliminating influence on environment, greatly reducing energy consumption, and ensuring that the method is a good energy-saving and emission-reduction method

Method for closed-loop production of silicon tetrafluoride by utilizing sulfuric acid and quartz sand

Disclosed is a process for production of silicon tetrafluoride which can reduce the cost for the silicon tetrafluoride production and can also reduce the quantities of waste products produced in the process. Also disclosed is an apparatus for use for the process. The method comprises the steps of: (a) a high-silica fluorosilicic acid production step in which a raw material (1) containing silicon dioxide is reacted with a mixed solution containing hydrofluoric acid and hydrofluosilicic acid to yield an aqueous high-silica fluorosilicic acid solution: (c) a silicon tetrafluoride production step in which the aqueous high-silica fluorosilicic acid solution is reacted with sulfuric acid to yield silicon tetrafluoride; and (d) a sulfuric acid production step in which a sulfuric acid fraction containing hydrogen fluoride which is a by-product in the silicon tetrafluoride production step (c) is subjected to water vapor distillation to yield sulfuric acid. The process is characterized in that the sulfuric acid produced in the step (d) is reused in the step (c).

Process for production of silicon tetrafluoride, and apparatus for the process

PROBLEM TO BE SOLVED: To provide a method of treating organic wastes which can form acetic acid at a high yield under gentler conditions and a method of producing the acetic acid SOLUTION: In a first process step, an intermediate of the acetic acid is formed by decomposing organic matter by a hydrothermal reaction under the conditions under which the feeding of oxygen is limited After the first process step, the oxygen is fed and the acetic acid is formed from the intermediate by a hydrothermal oxidation reaction in a second process step

Method of treating organic waste and method of producing acetic acid

PROBLEM TO BE SOLVED: To provide a method of manufacturing silicon tetrafluoride by which the manufacturing cost of the silicon tetrafluoride is reduced and the quantity of waste is decreased and a manufacturing apparatus using the same. SOLUTION: The method of manufacturing silicon tetrafluoride comprises a high silica fluorosilicic acid producing step (a) for producing the high silica fluorosilicic acid aqueous solution by reacting a raw material 1 containing silicon dioxide with a mixed liquid containing hydrofluoric acid and hydrofluorosilicic acid, a silicon tetrafluoride producing step (c) for producing silicon tetrafluoride by reacting the high silica fluorosilicic acid aqueous solution with sulfuric acid, and a sulfuric acid producing step (d) for producing sulfuric acid by steam distilling silicon tetrafluoride-containing sulfuric acid by-produced in the silicon tetrafluoride producing step(c). In the silicon tetrafluoride producing step (c), sulfuric acid produced in the sulfuric acid producing step (d) is recycled. COPYRIGHT: (C)2007,JPO&INPIT

Method of manufacturing silicon tetrafluoride and manufacturing apparatus using the same

PROBLEM TO BE SOLVED: To provide a method of manufacturing a high purity silicon and an apparatus for manufacturing the high purity silicon capable of reducing the manufacturing cost and stably mass-producing the high purity silicon SOLUTION: An arc plasma jet generating apparatus 11 has a jet generating part 21 for generating plasma jet, a silicon gas supply part 23 for supplying a fluorine-based silicon gas (SiF 4 ) or silane gas (SiH 4 ) to the plasma jet generated in the jet generating part 21, and a jetting port 21b for jetting the plasma jet to the outside A diffusion suppressing means 12 is provided extending from the jetting port 21b in the jetting direction so as to suppress the diffusion of the plasma jet A capturing means 14 is provided in front of the diffusion suppressing means 12 in the jetting direction so as to capture silicon produced by decomposition of the fluorine-based silicon gas or the silane gas from the plasma jet passing through the diffusion suppressing means 12 COPYRIGHT: (C)2008,JPO&INPIT

Moriya Takehiko

Papers

Process for production of silicon tetrafluoride, and apparatus for the process

Method of treating organic waste and method of producing acetic acid

Method of manufacturing silicon tetrafluoride and manufacturing apparatus using the same

Method of manufacturing high purity silicon and apparatus for manufacturing high purity silicon