五月的婷婷综合视频,五月的婷婷综合视频,美女日逼视频免费观看,狠狠干狠狠日狠狠爱,不卡视频一二三区免费视频,亚洲中文自拍另类在线,99久久99久久免费精品十八禁,97caopen视频,日本免费一曲二曲三曲

1. Basic product information

Chemical formula: C3H9BO3

Molecular weight: 103.91

CAS Registry Number: 121-43-7

EINECS login number: 204-468-9

2. Physical properties

Appearance: reddish brown liquid. Stable in dry air.

Density: 0.915

Melting point: -29 ℃

Boiling point: 67 ～ 68 ℃

Flash point: -8 ℃

Refractive index n20 / D: 1.3562-1.3582

Dissolution:

It is miscible with ether, methanol, hexane, tetrahydrofuran, etc. There is water decomposition in the presence of water.

It will hydrolyze into methanol and boric acid when meeting water. It is miscible with ether, tetrahydrofuran, isopropylamine, hexane, methanol, liquid paraffin and other organic solvents. combustible

3. Product Technology

1. It can be synthesized by various methods, such as preparation from pyridine-boron trifluoride composite, or methanol; boron fluoride; methanol; boric acid; methyl orthosilicate; boron halide, etc.

2. After boric acid is melted in a platinum container, the resulting boron oxide is quickly cooled and crushed, and then stored in a desiccator with phosphorus pentoxide.

Instrument; the neck of the three-necked round-bottom flask is the grinding mouth and the sliding head. A rubber stopper with a glass container R (for boron oxide) is plugged in A. The lower end of the container is opened and ground so that it can be closely connected with the leading glass ball valve ") upwards. The staggered stirrer E is used to break up lumps that may form near the outlet of the container. The B neck of the flask was connected to a condenser, and a U-shaped tube for containing calcium chloride was welded to the upper end of the flask. A rubber stopper with a bent glass rod F was inserted into the C neck as a stirrer.

When preparing methyl borate, close the R ball valve. Hold 75 grams of finely powdered boron oxide in R. Put 320 ml of absolute methanol from neck B and connect to the condenser. No i-1, loosen the ball valve D a little bit, boron oxide will fall into methanol at any desired speed, so that it can be used to control the process of exothermic reaction, so as to avoid excessive reaction. After adding boron oxychloride, rotate the glass rod F back and forth to stir the solution.

The addition of boron oxide should be fast enough to keep the mixture hot, but not so fast as to cause the solution to boil. This feeding process takes about 10 minutes. The reaction mixture was allowed to cool, and snow-white crystalline boric acid precipitated. The turbid liquid was decanted and distilled using a Johnson fractionation column to obtain 175 ml of an azeotropic mixture of methyl borate and methyl alcohol. The solution was treated with cold concentrated sulfuric acid to remove formazan-o and the bottom layer was discarded. Methyl borate was treated with sulfuric acid twice, fractionated by Johnson column, and sub-vacuum fractionated to obtain pure product with a yield of 42%

 Ethyl borate can be prepared by a similar method with a yield of 31%

3. Manufacturing method:

Add 0.5mol of borax, 16mol of methanol, 1mL of sulfuric acid to a reaction bottle equipped with a stirrer and fractionation device (fractionation column diameter 2.5cm, height 75cm, stainless steel spiral ring inside to achieve the effect of 15 theoretical trays) Slowly heated to reflux, most of the constant boiling sulfur effluent was collected at 54 ℃, and a small amount of distillate at 54 ～ 62 ℃. The total yield of trimethyl borate was 92.9%. [3]

Install a 2.5-meter-diameter and 75-cm-length fractionation column on a 1-liter round-bottom flask, and fill it with 4.} millimeters of stainless steel spiral to achieve an efficiency of 15 theories. Put 0.5 mole of borax (Na2B4O210H2O, 16 moles of methanol and 1 mole of sulfuric acid) in the bottle. Slowly distill the reaction mixture, azeotropically boil at 54 ° C to get most of the product, and a small portion at 54--62 ° C Obtained. Yield 92.9%

4. Purpose

1. Intermediate of potassium (sodium) boron hydride, vulcanizing agent, wood preservative, catalyst, gelling agent, heat stabilizer, hydrogen flame extinguishing agent, used for flame retardant treatment of cotton and preparation of activated silica, and used as carbohydrate Derivative gas chromatography analysis reagent.

2. Used as a doping source for semiconductors and also for the preparation of high-purity boron.

3. This product is used as a solvent for paraffin, resin, petroleum, ketone catalyst, and also used in the electronics industry.

4. Used as a solvent, dehydrogenation agent, insecticide and organic synthesis, semiconductor boron diffuser.

5. Gas chromatography analysis of derivatization reagents, solvents, ketone-making catalysts, semiconductor boron diffusion sources.

V. Essential materials for export of trimethyl borate

Cas number: 121-43-7, UN: 2416

Customs Code HS: 29209090

Tax rebate: The current tax rebate for triborate borate is 9%.

Raw materials: using methanol and boric acid as raw materials.

It belongs to several types of dangerous goods: At present, trimethyl borate belongs to 3 types of dangerous goods.

Packing: Net weight 200KG / galvanized iron barrel (16 tons in a small cabinet), 1000KG / IB barrel (18 tons in a small cabinet) or 23 tons of ISOTANK.