Mixed Cationic‐nonionic Surfactants and pH Adjustment Route to Synthesize High‐quality MCM‐48

Using the mixture of cetyltrimethylammonium bromide (CTAB) and p‐Octyl polyethylene glycol phenyl ether (OP‐10) as templates, siliceous MCM‐48 materials can be synthesized with low molar ratio of CTAB to silica (0.139:1) and low concentration of mixed surfactants (ca.5%) and within a wide range of OP‐10/CTAB ratio (0.08?0.25). The materials were characterized by X‐ray powder diffraction, N₂ adsorption/desorption isotherm, TEM, TG‐DSC and ²⁹Si MAS NMR. Measurements indicated that the use of mixed surfactants allowed better condensation and higher ordering of the cubic mesostructure; at the same time, some properties of these materials were sensitive to the OP‐10/CTAB ratio. It was also found that the reduced pH of the gel which had been crystallized for a certain time gave a highly reproducible synthesis with a high silica yield (about 95%). Furthermore, the reaction mechanism of the synthesis is discussed in detail.     

CoAPO-11分子筛的合成、表征和催化性能： 1-己烯异构化反应

水热法合成了钴取代磷铝酸盐分子筛CoAPO-11，并采用了X射线衍射、扫描电子显微镜、红外光谱、紫外可见光谱以及氮气吸脱附等表征手段对合成的样品进行表征，并在合成的分子筛上进行1-己烯异构化反应评价，并考查了温度和空速对反应的影响。结果表明，在反应温度300℃及空速为2.4h－1CoAPO-11分子筛对1-己烯异构化反应具有较好的催化性能。     

Two Novel Sub-skeleton Types of ent-Kauranoids from Isodon gesneroides

Two novel ent-kauranoids with new sub-skeleton types, gesneroidins G and H were isolated as white powder from the ether extract of the leaves of Isodon gesneroides through normal phase column chromatography. Their structures were elucidated as 3β,6α,7β-triacetoxyl-15-hydroxyl-14-oxo-ent- 15,16-seco-kaur-11,17-olide and Iα-hydroxyl-3β,6α,7β,11 β-tetraacetoxyl-ent-nor-15,17-kaur-8,16-olide on the basis of the spectral evidences including ID and 2D NMR spectra.     

New ent‐Abietanoids from Isodon rubescens

Six new ent‐abietane diterpenoids, rubescensins I–M ( 1 – 5 ) and P ( 6 ), along with two related acetonide derivatives ( 7 and 8 ), were isolated from Isodon rubescens. Their structures were elucidated by detailed spectroscopic analysis. Compound 5 is the first N‐containing diterpenoid from the genus Isodon, exhibiting notable cytotoxicity against human tumor K562 cells.     

含羧酸配体的鼓形有机锡氧簇合物：六聚苯基锡氧3-吲哚丁酸酯的合成及晶体结构

利用Ph3SnOH和3-吲哚丁酸以1：1摩尔比反应，合成了新型含羧酸配体的鼓形 有机锡氧簇合物：六聚苯基锡氧3-吲哚西酸酯。通过元素分析、红外光谱和X射线 单晶衍射对其结构进行了表征。测试结果表明：该化合物为三斜晶系，空间群P1， a=1.1722(6),b=1.5694（8）nm，c=1.7227(9)nm，α=116.251（8）°，β=100. 854（10）°，γ=95.606（9）°，Z=1，V=2.732(3)nm^3，Dc=1.554g·cm^-3，μ =1.420mm^-1，F(000)=1276，R=0.0630，ωR=0.0762。晶体结构中，六配位的锡原 子呈畸变的八面体构型。     

乙醇对超临界CO2中乙酰乙酸乙酯异构化平衡的影响

超临界流体（SCF）是物质所处的温度和压力同时高于其临界值时的流体．在超临界体系中存在特殊的分子间相互作用，从而使其具有诸如高压缩性、高扩散系数、强溶剂化力等许多独特的性质.在超临界流体研究领域引起人们普遍关注的问题之一是共溶剂效应（cosolventeffect），即在超     

Reactive dications: the superacid-catalyzed reactions of alkynes bearing adjacent N-heterocycles or amine groups

A variety of aminoalkynes and related heterocycles are reacted in the Bronsted superacid CF(3)SO(3)H (triflic acid), and products are obtained in generally good yields (69-99%) from Friedel-Crafts-type reactions. The reactions are consistent with the formation of novel dicationic intermediates having a vinyl cationic site and an adjacent protonated N-heterocycle or ammonium cation.     

The Aldol Reaction of Allenolates with Aldehydes in the Presence of Magnesium Diiodide (MgI2) as Catalyst

Stereoselective synthesis of (Z)‐α‐(hydroxyalkyl)‐β‐iodoacrylates (=(2Z)‐2‐(hydroxyalkyl)‐3‐iodoprop‐2‐enoates) was achieved in a one‐pot coupling reaction from methyl prop‐2‐ynoate, Me₃SiI, and an alkanal under mild conditions with MgI₂ as catalyst (→ 1 – 9 ; see Table and Scheme 1). Baylis‐Hillman β‐iodo adducts were generated in excellent yields with high (Z)‐selectivity. The conversion of methyl prop‐2‐ynoate to an active methyl 3‐iodo‐1‐[(trimethylsilyl)oxy]allenolate intermediate in situ followed by carbonyl addition is proposed as the reaction sequence (Schemes 1 and 2).     

Determination of Biodegradation Process of Benzene, Toluene, Ethylbenzene and Xylenes in Seabed Sediment by Purge and Trap Gas Chromatography

Benzene, toluene, ethylbenzene, and xylenes (BTEX) are commonly found in crude oil and are used in geochemical investigations as direct indicators of the presence of oil and gas. BTEX are easily volatile and can be degraded by microorganisms, which affect their precise measurement seriously. A method for determining the biodegradation process of BTEX in seabed sediment using dynamic headspace (purge and trap) gas chromatography with a photoionization detector (PID) was developed, which had a detection limit of 7.3–13.2 ng L^?1 and a recovery rate of 91.6–95.0%. The decrease in the concentration of BTEX components was monitored in seabed sediment samples, which was caused by microorganism biodegradation. The results of BTEX biodegradation process were of great significance in the collection, transportation, preservation, and measurement of seabed sediment samples in the geochemical investigations of oil and gas.