The reaction mechanism of IA/MA copolymer system andcotton cellulose is conjectured and verified, the two keysteps, such as the formation of cyclic anhydride interme-diates and the building of ester crosslinklng, and ...The reaction mechanism of IA/MA copolymer system andcotton cellulose is conjectured and verified, the two keysteps, such as the formation of cyclic anhydride interme-diates and the building of ester crosslinklng, and the ef-fect of sodium hypophosphite are especially emphasized,by FT - IR spectroscopy and acid- base titration anal-yses. The experiments reveal that carboxylic acids main.ly change to cyclic anhydride in the pre - drying step andSodium Hypophosphite (SHP) has effect on it, but mostester - crosslinkages are built in the curing step and SHPhas effects on both anhydride formation and ester -crosslinking formation.展开更多
The formation of organic peroxides in the Cl\|atom\|initiated photooxidation of CH\-4 in O\-2\|N\-2 mixtures at 101 325 Pa and 298 K was studied with HPLC and FT\|IR methods. Four peroxidic products were detected, whi...The formation of organic peroxides in the Cl\|atom\|initiated photooxidation of CH\-4 in O\-2\|N\-2 mixtures at 101 325 Pa and 298 K was studied with HPLC and FT\|IR methods. Four peroxidic products were detected, which were H\-2O\-2, hydroxymethyl hydroperoxide (HOCH\-2OOH; HMHP), methyl peroxide (CH\-3OOH; MHP) and dimethyl peroxide (CH\-3OOCH\-3). A chromatogram peak at retention time of 8.08 min was assigned tentatively to peroxyformic acid (HC(O)OOH). The identification of HMHP in the reaction system showed that one of the reaction paths for the self\|reaction of CH\-3OO· led to producing Criegee intermediate ·CH\-2OO·. The formation mechanism of organic peroxide in the photooxidation of CH\-4 is more complicated than it was assumed before. Photooxidation of CH\-4 is probably an important source of organic peroxides in the troposphere.展开更多
文摘The reaction mechanism of IA/MA copolymer system andcotton cellulose is conjectured and verified, the two keysteps, such as the formation of cyclic anhydride interme-diates and the building of ester crosslinklng, and the ef-fect of sodium hypophosphite are especially emphasized,by FT - IR spectroscopy and acid- base titration anal-yses. The experiments reveal that carboxylic acids main.ly change to cyclic anhydride in the pre - drying step andSodium Hypophosphite (SHP) has effect on it, but mostester - crosslinkages are built in the curing step and SHPhas effects on both anhydride formation and ester -crosslinking formation.
文摘The formation of organic peroxides in the Cl\|atom\|initiated photooxidation of CH\-4 in O\-2\|N\-2 mixtures at 101 325 Pa and 298 K was studied with HPLC and FT\|IR methods. Four peroxidic products were detected, which were H\-2O\-2, hydroxymethyl hydroperoxide (HOCH\-2OOH; HMHP), methyl peroxide (CH\-3OOH; MHP) and dimethyl peroxide (CH\-3OOCH\-3). A chromatogram peak at retention time of 8.08 min was assigned tentatively to peroxyformic acid (HC(O)OOH). The identification of HMHP in the reaction system showed that one of the reaction paths for the self\|reaction of CH\-3OO· led to producing Criegee intermediate ·CH\-2OO·. The formation mechanism of organic peroxide in the photooxidation of CH\-4 is more complicated than it was assumed before. Photooxidation of CH\-4 is probably an important source of organic peroxides in the troposphere.
