The paper presents a method to determine hydrocarbon types of aromatic fraction from residue by high ionizing voltage,low resolution MS. the asphaltenes in the residue samples were precipitated using n-heptane. The he...The paper presents a method to determine hydrocarbon types of aromatic fraction from residue by high ionizing voltage,low resolution MS. the asphaltenes in the residue samples were precipitated using n-heptane. The heptane-soluble components were further fractionated into saturates,aromatics and resins on the alumina/silica gel column. Then the aromatic fractions were analyzed on a VG Autospec mass spectrometer with a HP5890 GC. All glass heated inlet system was used to vaporize the sample into the gaseous phase. the mass spectrometric data were processed using group-type methods. the calculations were carried out to sum the relative abundance of characteristic peaks of each class,and each summation of peaks indicates corresponding hydrocarbon type. The analyses show that the vaporizing temperature has little impact on the composition at certain temperature ranges and the tests produce highly repeatable results.展开更多
A novel catalyst, MgFe 2O 4, for hydroxylation of phenol with hydrogen peroxide was synthesized via coprecipitation method from an aqueous solution containing Fe(NO 3) 3·9H 2O and Mg(NO 3) 2·6H 2O with ammon...A novel catalyst, MgFe 2O 4, for hydroxylation of phenol with hydrogen peroxide was synthesized via coprecipitation method from an aqueous solution containing Fe(NO 3) 3·9H 2O and Mg(NO 3) 2·6H 2O with ammonia. The X ray diffraction peaks of the catalyst show that the as prepared sample has engendered MgFe 2O 4 crystal with spinel structure, which is also confirmed by its IR spectrum. In the hydroxylation of phenol with hydrogen peroxide, MgFe 2O 4 catalyst exhibited high activity after a short induction period. In particular, the addition of a little amount of acetic acid in the reaction liquid can effectively shorten the induction period. Under the same reaction conditions, the diphenol selectivity over MgFe 2O 4 is higher than that over TS 1, furthermore, the reaction time is shortened greatly. The experimental phenomena can be explained by the free radical mechanism.展开更多
文摘The paper presents a method to determine hydrocarbon types of aromatic fraction from residue by high ionizing voltage,low resolution MS. the asphaltenes in the residue samples were precipitated using n-heptane. The heptane-soluble components were further fractionated into saturates,aromatics and resins on the alumina/silica gel column. Then the aromatic fractions were analyzed on a VG Autospec mass spectrometer with a HP5890 GC. All glass heated inlet system was used to vaporize the sample into the gaseous phase. the mass spectrometric data were processed using group-type methods. the calculations were carried out to sum the relative abundance of characteristic peaks of each class,and each summation of peaks indicates corresponding hydrocarbon type. The analyses show that the vaporizing temperature has little impact on the composition at certain temperature ranges and the tests produce highly repeatable results.
文摘A novel catalyst, MgFe 2O 4, for hydroxylation of phenol with hydrogen peroxide was synthesized via coprecipitation method from an aqueous solution containing Fe(NO 3) 3·9H 2O and Mg(NO 3) 2·6H 2O with ammonia. The X ray diffraction peaks of the catalyst show that the as prepared sample has engendered MgFe 2O 4 crystal with spinel structure, which is also confirmed by its IR spectrum. In the hydroxylation of phenol with hydrogen peroxide, MgFe 2O 4 catalyst exhibited high activity after a short induction period. In particular, the addition of a little amount of acetic acid in the reaction liquid can effectively shorten the induction period. Under the same reaction conditions, the diphenol selectivity over MgFe 2O 4 is higher than that over TS 1, furthermore, the reaction time is shortened greatly. The experimental phenomena can be explained by the free radical mechanism.
