Catalysts peroxide

Current Polymerisation Catalysts—Peroxide, and Other Initiators, muIti-cHent study. Catalyst Consultants, Inc., Spring House, Pa., Nov. 1991. 

Lepidocrocite (-y-FeOOH) has also been used as a catalyst for Fentonlike reactions [54]. First-order decomposition of hydrogen peroxide was observed in the presence of this catalyst. Peroxide decay at 20 g/L catalyst was found to be pseudo-first-order and pH-dependent, with rate constant values reported from 0.102 hr-1 at pH 3.3 to 0.326 hr-1 at pH 8.9. In this system benzoic acid degradation was fastest at the low pH value. Under these conditions, acid dissolution of the lepidocrocite was observed to produce... 

In the presence of cinchona derivatives as catalysts, peroxides or hypochlorites as Michael donors react with electron-deficient olefins to give epoxides via conjugate addition-intramolecular cyclization sequence reactions. Two complementary methodologies have been developed for the asymmetric epoxidation of electron-poor olefins, in which either cinchona-based phase-transfer catalysts or 9-amino-9(deoxy)-epi-dnchona alkaloids are used as organocatalysts. Mechanistically, in these two... 

Alternatively, as in Wacker Chemie s MONOSIL process, the extrusion steps can be combined into a one-step process for aeating a readily crosslinkable compound. Other suppliers such as Dow Coming have also tried to make one-step crosslinking easier for processors by offering preblended formulations that contain the aosslinking catalyst, peroxide and silane agent in one PE compoimd [15-3, 15-4). 

Storage Moisture-sensitive store in a cool, dry place keep away from heat and open flame Uses Fragrance intermediate in cosmetics, personal care raw material in pharmaceuticals, vitamins, herbicides, pesticides, food chems., flavors, plasticizers (e.g., sucrose acetate isobutyrate), catalysts, peroxides chem. processing Manuf./Distrib. Aldrich http //www.sigma-aldrich.com, Celanese http //www. celanesechemicals. com, http //www.chemvip.com, Daicel Chem. Ind. http //www.daicei.co.jp, Eastman http //www.eastman.com, Fluka http //WWW. sigma-aidrich. com Trade Name Synonyms Eastman Isobutyric Anhydride [Eastman http //www.eastman.com], Eastman Isobutyric Anhydride, Kosher [Eastman http //www.eastman.com]... 

Polyester and vinyl esters. Polyester matrices have had the longest period of use, with wide application in many large structural applications. (See Table 2.31.) They will cure at room temperature with a catalyst (peroxide) which produces an exothermic reaction. The resultant polymer is nonpolar and very water resistant, making it an excellent choice in the marine construction field. The isopolyester resins, regarded as the most water-resistant polymer in the polymer group, has been chosen as the prime matrix material for use on a fleet of U.S. Navy mine hunters. 

A typical composition for BMC and SMC includes base resins, catalysts, peroxides accelerators, fillers/chopped GF, thickeners and other additives. The base resins that are usually used are either polyester-based (orthophthalic or isophthalic), which are used with styrene, acrylic, vinyl toluene or di-allyl-phthalate (DAP) monomers, as crosslinkers, or styrene type monomers for general purpose products. Acrylic base resins are used for low shrinkage, while vinyl type monomers for high hot strengths (heat deflection temperatures). Catalysts are used for polyester type resins. Peroxides, such as benzoyl peroxide (BPO) and butyl perbenzoate are used as high temperature catalysts. 

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