- Electrophilic bromination in flow: A safe and sustainable alternative to the use of molecular bromine in batch
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Bromination reactions are crucial in today’s chemical industry since the versatility of the formed organobromides makes them suitable building blocks for numerous syntheses. However, the use of the toxic and highly reactive molecular bromine (Br2) makes these brominations very challenging and hazardous. We describe here a safe and straightforward protocol for bromination in continuous flow. The hazardous Br2 or KOBr is generated in situ by reacting an oxidant (NaOCl) with HBr or KBr, respectively, which is directly coupled to the bromination reaction and a quench of residual bromine. This protocol was demonstrated by polybrominating both alkenes and aromatic substrates in a wide variety of solvents, with yields ranging from 78% to 99%. The protocol can easily be adapted for the bromination of other substrates in an academic and industrial environment.
- Van Kerrebroeck, Reinout,Naert, Pieter,Heugebaert, Thomas S.A.,D’hooghe, Matthias,Stevens, Christian V.
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- Method for preparing hexabromocyclododecane
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The invention discloses a method for preparing hexabromocyclododecane. A 1-methyl-3-propanesulfonic imidazole disulfate ion liquid catalyst is used. Compared with the hexabromocyclododecane prepared by a method in the prior art, the hexabromocyclododecane prepared by the method provided by the invention has the advantage that the melting point is improved and can reach 197 DEG C or higher. The method provided by the invention has the advantages that the cost is low; the operation is simple; safety and environment-friendly effects are achieved; the industrial application is easy.
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Paragraph 0023; 0024; 0025; 0026
(2018/09/08)
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- New process for producing hexabromocyclododecane
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The invention discloses a new process for producing hexabromocyclododecane. 1-butyl-3-propanesulfonic acid imidazolium hexafluorophosphate ionic liquid catalyst is adopted. Compared with hexabromocyclododecane prepared with the method in the prior art, hexabromocyclododecane prepared with the new process has higher melting point up to 195 DEG C or higher. The method has the advantages of being lowin cost, easy to operate, safe and environmentally friendly and facilitates industrial application.
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Paragraph 0024; 0025; 0027
(2018/09/13)
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- A preparation method of double-ring (by machine translation)
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The invention discloses a method for preparing-ring cyclododecane, including brominated, washing and separating, drying three steps. Bromide is the raw material ring dodecatrienoic and bromine are respectively drop adding isobutyl alcohol and dichloroethane in the mixed solvent, bromine and ring dodecatrienoic molar ratio of 3.05 - 3.08: 1. Dropping process is divided into three sections of heating up to 50 °C ± 2 °C, the total reaction time is 3 - 4 hours; washing and separating, in the bromination reaction compatibility of the separated solid phase into the dichloroethane with preparation of isobutyl alcohol mixed solvent, stirring and mixing and then separating the solid phase, then adding ethanol washing 2 times, filtered and the solid phase. The separation is washing the separated solid phase in 80 °C ± 2 °C drying, to obtain white solid powder product. The present invention provides a method for preparing cyclododecatriene, the method of washing of the solvent, the product is entrained will affect the melting point of the fully impurities not bromide, the product purity, make the product melting point rises. (by machine translation)
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Paragraph 0016; 0017
(2017/08/25)
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- Preparation process for hexabromocyclododecane
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The invention discloses a preparation process for hexabromocyclododecane and belongs to the field of production of chemical products. The preparation process includes the steps of bromination, separation, drying and powder screening. According to the step of bromination, bromine and cyclododecatriene are added into a mixed solvent of isobutanol and chloroform dropwise for a reaction, the reaction dropwise-adding speed is controlled, and heat preservation curing is conducted after bromine and cyclododecatriene are added dropwise; the mass ratio of isobutanol to isobutanol in the mixed solvent is (0.8-1.0):1; the molar ratio of added bromine to added cyclododecatriene is (3.12-3.19):1, and the mass ratio of bromine to the solvent is 1:1.7. According to the step of separation, the material obtained after the reaction is subjected to suction filtration, the material obtained after suction filtration is poured into a centrifuge, and the material obtained after centrifugation is sequentially subjected to alkali washing and water washing. The material obtained after separation and water washing is dried and subjected to powder screening, and the product is obtained.
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Paragraph 0015; 0016; 0023; 0024
(2018/02/04)
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- High content of isomers of hexabromocyclododecane γ process for the preparation of
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The invention relates to a method for preparing hexabromocyclododecane. A water-containing mixed solvent is used as a reaction medium, wherein the mixed solvent comprises hydrochloric ether and low molecular fatty alcohol with carbon number smaller than 10; inorganic acid salt or organic acid salt is added to the water-containing mixed solvent, so that the water-containing mixed solvent achieves a dissolved saturation condition; the permissible moisture content in the mixed solvent can be increased to 10wt%. The selectivity and the product yield of the hexabromocyclododecane gamma isomer are improved by utilizing the preparation method disclosed by the invention; and moreover, the product grain size is small and the bulk density is low, so that the dispersion in the polymer is facilitated.
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Paragraph 0028-0032
(2016/10/08)
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