CAS NO 821-06-7 trans-1 4-Dibromo-2-butene

Production methods: 1. By 1,3-butadiene reaction with bromine: 126g of liquid 1,3-butadiene was added to cool to -5 ~ 15 ℃ 250mL carbon tetrachloride solution, with stirring Add 76mL bromine dissolved in 100mL carbon tetrachloride solution. After placing the carbon tetrachloride vacuum distillation, adding about the same volume of petroleum ether, the temperature is 60 ~ 90 ° C, filtered while hot, the filtrate was cooled and precipitated dibromo 172.8g, after standing 10d and 78.5g precipitation The finished product 251.3g, yield 79%.
2. Method: equipped with a stirrer, dropping funnel, ventilation catheter 10L reaction flask, add anhydrous carbon tetrachloride 5L, cooled to -20 ℃. Slowly pass 1,3-butadiene
(2) 430g (8mol), and then slowly dropwise added by bromine 800g (5.0mol) dissolved in 2L anhydrous carbon tetrachloride dubbed solution, about 1.5h plus finished. Slowly rise slowly to room temperature. The solvent was recovered under reduced pressure and the residue was recrystallized from petroleum ether to give trans 1,4-dibromo-2-butene.
Uses: used as organic synthesis intermediates

Product expansion
1> Cosmetic Raw Materials: Cosmetics is a variety of raw materials through a reasonable deployment of processing from the compound mixture. Cosmetics with a wide range of raw materials, different performance. According to the raw material properties and uses of cosmetics, can be divided into matrix materials and auxiliary raw materials in two categories. The former is a class of cosmetics in the main raw materials, cosmetics in the possession of a large proportion of the cosmetics play a major role in the role of the material. The latter is the formation of cosmetics, stability or to give color, smell and other characteristics of the role of these substances in the cosmetic formula is not used, but it is extremely important. Cosmetics are natural, synthetic or extracted from the role of different substances as raw materials, by heating, mixing and emulsification and other production processes processed from the chemical mixture.
2> Active Pharmaceutical Ingredients(API): API refers to the raw materials in the production of various types of preparations, which is the active ingredient in powder,crystal and paste for medicine use through chemical synthesis,plant extract, and preparations of biotechnology institute.It is one substance or mixture during the medicine making period, it can not be taken directly by patients.
3> Fragrance And Spices: Spice is a substance that can be scented by smelling or scented by taste, and is the raw material for the preparation of the fragrance. Spices are an important part of fine chemicals, it is composed of natural spices, synthetic spices and single fragrance.
4> Organic Raw Material: Intermediates are also known as organic intermediates. The use of coal tar or petroleum products as raw materials to produce dyes, pesticides, pharmaceuticals, resins, additives, and other intermediates.
5> Chemicals Used In Paints: Paint, the traditional Chinese name is paint. So-called coating is coated on the surface of the object that be protected or be adornment, and with the continuous film coating to form strong adhesion, usually in resin, or oil, or emulsion is given priority to, add or not add pigment, filler, add the corresponding additives, organic solvents or water preparation of viscous liquid.