磷钼酸季铵盐催化柴油氧化脱硫研究

Catalytic oxidative desulfurization of diesel fuel by quaternary ammonium phosphomolybdate

以十八烷基三甲基磷钼酸铵作催化剂、H2O2作氧化剂,对模型油和直馏柴油进行了氧化脱硫研究。结果表明,相同反应条件下,以磷钼酸季铵盐作催化剂时,二苯并噻吩(DBT)和苯并噻吩(BT)的脱除率比磷钼酸作催化剂分别提高了5.3倍和2.4倍;在70℃下反应2.5 h,DBT、BT的脱除率分别达到100%和40.5%;动力学研究表明,DBT、BT的催化氧化反应皆符合表观一级动力学规律,其活化能分别为2 2.5 kJ/mol和62.4 kJ/mol;各反应条件对直馏柴油脱硫率的影响大小顺序为:催化剂用量>反应时间>氧化剂用量>反应温度;在m(催化剂)/m(柴油)=1.8%、V(H2O2)/V(柴油)=2.5%、反应温度70℃、反应时间3 h条件下,柴油的脱硫率达88.7%,收得率不低于99%。

The oxidative desulfurization of model oil and straight-run diesel catalyzed by octadecyl trimethyl ammonium phosphomolybdate was studied with the aqueous solution of H2O2 as the oxidant. It is shown that under the same reaction conditions, the conversion rates of dibenzothiophene （DBT） and benzothiophene （BT） are 5.3 times and 2.4 times higher catalyzed by quaternary ammonium phos- phomolybdate than by phosphomolybdic acid, respectively. The conversion rates of DBT and BT can be up to 100% and 40.5% under 70℃ and 2.5 h, respectively. Both the oxidative reactions of DBT and BT are in conformity with first order kinetics, and the apparent activation energies are 22.5 KJ/ tool and 62.4 KJ/mol, respectively. The influential factors for desulfurization of straight-run diesel are catalyst dosage〉reaction time,hydrogen peroxide dosage〉reaction temperature. Under the condition of m（catalyst）/m（diesel） 1.8%,v（H2O2）/v（diesel） 2.5%,70℃ and 3 h, the desulfurization rate of diesel is 88.7% with the recovery rate no less than 99%.