A new solid acid SO_4^(2-)/TiO_2 catalyst modified with tin to synthesize 1,6-hexanediol diacrylate

A new solid acid catalyst,SO4^2-/TiO2 modified with tin,was prepared using a sol-gel method and its physicochemical properties were revealed by nitrogen adsorption-desorption,X-ray powder diffraction,scanning electron microscopy,Fourier transform infrared spectroscopy,infrared spectroscopy of adsorbed pyridine,temperature-programmed desorption of ammonia and thermal gravimetric analysis.The structure,acidity and thermal stability of the SO4^2-/TiO2-SnO2 catalyst were studied.Incorporating tin enlarged the specific surface area and decreased crystallite size of the SO4^2-/TiO2 catalyst.The total acid sites of the modified catalyst increased and Bronsted acid strength remarkably increased with increasing tin content.The decomposition temperature of sulfate radical in the modified catalyst was 100 ℃ greater and its mass loss was more than twice that of the SO4^2-/TiO2 catalyst.The SO4^2-/TiO2-SnO2 catalyst was designed to synthesize 1,6-hexanediol diacrylate by esterification of 1,6-hexanediol with crylic acid.The yield of 1,6-hexanediol diacrylate exceeded 87% under the optimal reaction conditions：crylic acid to 1,6-hexanediol molar ratio = 3.5,catalyst loading = 7%,reaction temperature = 130 ℃ and reaction time = 3 h.The modified catalyst exhibited excellent reusability and after 10 cycles the conversion of 1,6-hexanediol was above 81%.

Recent advances on controllable and selective catalytic oxidation of cyclohexene

Because of multiple potential reaction sites and variable oxidation depths,oxidation of cyclohexene can lead to a mixture of products with different oxidation states and functional groups,such as 7-oxabicyclo[4.1.0]heptane,trans/cis-cyclohexane-1,2-diol,cyclohex-2-en-1-ol,cyclohex-2-en-1-one,and even adipic acid.These products are broadly and abundantly used intermediates in the chemical industry;therefore,controllable oxidation reactions for cyclohexene that can selectively afford the targeted products are synthetically valuable for applications in both the academy and industry,thus becoming the aim of synthetic and catalytic chemists in the field.Many reports on selective oxidation of cyclohexene have recently appeared in the literature because of its significance.This short review summarizes the recent advances on this subject,and the contents are mainly classified based on the chosen oxidants.We hope that this review can provide a useful guide for controllable and selective catalytic oxidation of cyclohexene for interested readers from both the academy and industry.

斑唇马先蒿化学成分的研究

目的研究斑唇马先蒿Pedicularis longiflora var.tubiformis的化学成分。方法采用正相硅胶柱色谱、反相RP18硅胶柱色谱、凝胶柱色谱方法进行分离纯化,利用理化性质及波谱数据分析鉴定化合物结构。结果从斑唇马先蒿的乙醇提取部位中分离得到20个化合物,分别鉴定为正二十六烷醇(1)、正三十六烷醇(2)、正三十九烷醇(3)、β-谷甾醇(4)、己二烯二酸(5)、肉桂酸(6)、对甲酰基肉桂酸(7)、β-胡萝卜苷(8)、芹菜素(9)、刺槐素(10)、木犀草素(11)、金圣草黄素(12)、苜蓿素(13)、东莨菪素(14)、1-羟基呫吨酮(15)、木犀草素-5-O-β-D-葡萄糖苷(16)、荭草苷(17)、槲皮素-4′-O-D-半乳糖(18)、木犀草素-7-O-β-D-葡萄糖苷(19)、毛蕊花苷(20)。结论化合物1～8、10、14～18和20均为首次从该植物中分离得到。

毛麝香的化学成分研究

目的对毛麝香Adenosma glutinosum全草进行化学成分研究。方法采用硅胶柱色谱、ODS、凝胶Sephadex LH-20柱色谱、半制备液相色谱等技术进行分离纯化,经现代波谱数据分析以及物理常数对照等方法鉴定化合物结构。结果从毛麝香95%乙醇提取物中分离得到11个化合物,分别鉴定为白桦脂酸(1)、白桦脂醇(2)、3β-羟基-乌苏烷-11-烯-13β,28-内酯(3)、乌苏酸(4)、对羟基苯甲酸(5)、反式对羟基肉桂酸(6)、对羟基苯甲醛(7)、富马酸(8)、己二烯二酸(9)、5,6-二羟基-7,8,4′-三甲氧基黄酮(10)、7-羟基胡椒酮(11)。结论所有化合物均为首次从毛麝香中分离得到。