硫化氢供体分子研究进展

硫化氢(H2S)是一种内源性的气体信使分子,具有极其广泛的生物学活性,包括舒张血管、保护心脏、抗炎、抗氧化、抗肿瘤等。和其他气体信使分子一样,H2S的活性和其释放的部位、浓度以及持续时间密切相关。因此,H2S供体药物研究的关键科学问题在于如何提高H2S供体分子的选择性,在靶部位(一般为病变部位)释放适当浓度的H2S,发挥治疗作用的同时限制其不良反应。本文综述了两大类H2S供体分子的结构及其释放H2S的机制,重点介绍近年来发展的具有可控释放潜力的H2S供体药物,旨在为H2S供体药物研究提供新的思路。

液化气和天然气液吸附脱硫新工艺

烃类脱硫或称脱臭工艺，主要是先进行溶剂处理（如胺洗）脱除硫化氢（H2S）；然后再碱洗，除去液化气中的硫醇和羰基硫化物（COS），其反应式为：COS＋4NaOH→Na2s＋Na2C02＋2H20，RSH＋NaOH→RSNa＋H2O。

气体脱硫醇的新方法

据英国《石油技术季刊》四季报道，气体加工厂的要求是深度脱除硫化物，除了脱除硫化氢外，还要求脱除羰基硫化物和硫醇。陶氏（Dow）化学公司的气体处理产品和服务公司开发了一种脱除硫醇的新方法，能够大大提高胺溶剂脱硫醇的能力。据陶氏化学公司提供的信息，现有胺洗装置提高脱硫醇的效率有以下四个优点：一是能够去除或缩小下游处理装置的规模；二是提高效率并延长分子筛装置的运转周期；三是减少或不产生碱洗塔的硫醇盐或二硫化物废料；四是减少处理后气体中或天然气液体中的总硫含量，因而提升其价值。

Hydrolysis of Carbonyl Sulfide in Binary Mixture of Diethylene Glycol Diethyl Ether and Water

The solubility and hydrolysis of carbonyl sulfide in binary mixture of diethylene glycol diethyl ether and water are studied as a function of composition. The use of an aqueous solution of diethylene glycol diethyl ether enhances the solubility and hydrolysis rate of carbonyl sulfide compared with that in pure water. The composition of the mixture with maximum hydrolysis rate varies with temperature. The thermophysical properties including density, viscosity, and surface tension as a function of composition at 20℃ under atmospheric pressure as well as liquid-liquid equilibrium (LLE) data over the temperature range from 28℃ to 90℃ are also measured for the binary mixture.

Emissions of Biogenic Sulfur Gases(H2S,COS)from Phragmites australis Coastal Marsh in the Yellow River Estuary of China

Emissions of biogenic sulfur gases(hydrogen sulfide(H_2S) and carbonyl sulfide(COS)) from Phragmites australis coastal marsh in the Yellow River estuary of China were determined during April to December in 2014 using static chamber-gas chromatography technique with monthly sampling. The results showed that the fluxes of H_2S and COS both had distinct seasonal and diurnal variations. The H_2S fluxes ranged from 0.09 μg/(m^2·h) to 7.65 μg/(m^2·h), and the COS fluxes ranged from –1.10 μg/(m^2·h) to 3.32 μg/(m^2·h). The mean fluxes of H_2S and COS from the P. australis coastal marsh were 2.28 μg/(m^2·h), and 1.05 μg/(m^2·h), respectively. The P. australis coastal marsh was the emission source of both H_2S and COS over the whole year. Fluxes of H_2S and COS were both higher in plant growing season than in the non-growing season. Temperature had a dramatic effect on the H_2S emission flux, while the correlations between COS flux and the environmental factors were not found during sampling periods. More in-depth and comprehensive research on other related factors, such as vegetation, sediment substrates, and tidal action is needed to discover and further understand the key factors and the release mechanism of sulfur gases.

Catalytic hydrolysis of carbonyl sulfide over modified coal-based activated carbons by loading metal

A novel type of metal oxide/activated carbon catalyst was prepared by sol-gel method for the hydrolysis of carbonyl sulfide （COS）. The influences of the calcination temperature, additive content （2.5%-10.0% Fe2O3, mass fraction） and the basic density of the activation process were thoroughly investigated. The surface of catalysts was characterized by Boehm titration. The products were characterized by scanning electron microscopy （SEM）, X-ray diffractometry （XRD） and X-ray photoelectron spectroscopy （XPS）. The results show that catalysts with 2.5%-5.0% Fe2O3 after calcining at 500 ℃ have superior activity. The conversion rate of COS increases with increasing the relative density of basic capacity loaded onto activated carbon（AC）, and the activity follows the order： KOH〉Na2CO3 〉NaHCO3. Boehm titration data clearly show that the total acidity increases （from 0.06 to 0.48 mmol/g） and the basic groups decrease （from 0.78 to 0.56 mmol/g） after COS hydrolysis and H2S adsorption. The XPS results show that the product of HzS may be absorbed by the interaction with metal compounds and 02 to form sulfate （171.28 eV） and element sulfur （164.44 eV）, which lead to catalysts poisoning.

Solubilization of small molecules from coal and the resulting effects on the pore structure distribution

The solubilization of small molecules from coal by solvent extraction and the resulting effects on the pore distribution of a low rank coal were studied. Samples were extracted, in succession, with petroleum ether and with CS2. Extract and residue fractions collected during the solubilization process were analyzed by FTIR and by surface area and porosimetry. The results show that an obvious inflection point exists that allows separating the dissolution sequence into stages. Small molecules are first extracted from the free state, then molecules trapped in micropores are extracted and, finally, molecules trapped in the coal-matrix network are extracted. This is indicated from the extraction yield curves. Chain-like carbonyl compounds, -OH (or -NH) containing compounds that are hydrogen bonded and phenolics dominate the petroleum ether extracts. Chain-like carbonyl components and ether compounds (aliphatic ethers and aromatic ethers) dominate the CS2 extracts. A solvent dissolution mechanism and the effect of small molecule extraction on the pore structure are put forward. Diffusion, dissolution, pore opening, pore shrinking or even collapsing caused by swelling, creating of new micropores, pore opening and, finally, colloidallization of some micropores occurs. In the later stages of the extraction the internal structure of the coal is colloidallized due to swelling and the pore number or volume is greatly reduced.

Heterogeneous oxidation of carbonyl sulfide on mineral oxides

Heterogeneous oxidation of carbonyl sulfide (OCS) on mineral oxides including SiO2,Fe2O3,CaO,MgO,ZnO and TiO2,which are the main components of atmospheric particles,were investigated using in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS),ion chromatography (IC),temperature-programmed desorption (TPD),X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) methods. The main products and intermediates of the heterogeneous oxidation of OCS on these oxides were identified with in situ DRIFTS and IC. The reaction mechanism and kinetics were also discussed. It is found that the reaction mechanism on these mineral oxides is the same as that on Al2O3 for the same final products and the intermediates at room temperature. Namely,OCS can be catalytically oxidized to produce surface SO42- species and gaseous CO2 through the surface hydrogen thiocarbonate (HSCO2-) and HSO3- species. The activity series for heterogeneous oxidation of OCS follows: Al2O3 ≈ CaO > MgO > TiO2 ≈ ZnO > Fe2O3 > SiO2. The specific area,basic hydroxyl and surface basicity of these oxides have effect on the reactivity. This study suggests that heterogeneous reactions of OCS on mineral dust may be an unneglectable sink of OCS.

Mechanism of the heterogeneous reaction of carbonyl sulfide with typical compo-nents of atmospheric aerosol

The homogeneous reactions of carbonyl sulfide (COS) with OH and oxygen radicals have been studied thor- oughly. However, the heterogeneous chemical processes in- volving COS and atmospheric particles are still not well un- derstood. The reactivity of COS with atmospheric mineral oxides such as Al2O3, CaO, SiO2, Fe2O3 and MnO2 has been explored. The gaseous and solid products of the reaction were identified by in situ Fourier transform infrared spec- troscopy and X-ray photoelectron spectroscopy respectively. The mechanism and kinetics of the heterogeneous reaction are also discussed in detail. The results showed that COS can be catalytically oxidized on the surfaces of different atmos- pheric mineral oxides with the products of CO2, S and SO4 . 2? The reactivity of the oxides with COS differs widely. Al2O3 exhibits excellent reactivity, and Fe2O3 is inferior to it. CaO shows weak reactivity, while SiO2 and MnO2 nearly have no activity for the oxidation of COS. The absorbed oxygen and hydroxyls on the surfaces of the oxides are the main active sites in the conversion of COS. When O2 in the experimental system was much excessive, the catalytic oxidation on the surface of Al2O3 is a pseudo first order reaction with respect to COS. The acidity of Al2O3 influences the reactivity signifi- cantly. The rate constants of the catalytic oxidation of COS on the surface of basic, neutral and acidic Al2O3 are respec- tively 1.51×10?4, 9.81×10?5 and 3.06×10?6 s?1.

新脱硫催化剂可延长燃料电池的使用寿命

日本太阳石油公司（Taiyo）主导的一个研究团体开发了一种高功能脱硫催化剂，能从液化石油气中除去对燃料电池有害的硫，从而延长燃料电池的使用寿命和缩小他们的尺寸。开发的这种镍支撑的氧化铝催化剂系用溅射法制得，与现有的镍基催化剂相比，这种新催化剂能将硫脱除至相同的程度，但比现有催化剂先进的是它能完全除去羰基硫化物。

Catalytic oxidation of CS_2 over atmospheric particles and oxide catalysts

The catalytic oxidization of CS2 over atmospheric particles and some oxide catalysts was explored through FT-IR, MS and a fixed-bed stainless steel reactor. The results show that atmospheric particles and some oxide catalysts exhibited considerable oxidizing activities for CS2 at ambient temperature. The reaction products are mainly COS and elemental sulfur, even CO2 on some catalysts. Among the catalysts, CaO has the strongest catalytic activity for oxidizing CS2. Fe2O3 is weaker than CaO. The catalytic activity for Al2O3 reduces considerably compared with the former two catalysts, and SiO2 the weakest. Atmospheric particle samples’ catalytic activity is between Fe2O3’s and Al2O3’s. The atmospheric particle sample collected mainly consists of Ca(Al2Si2O8) · 4H2O, which is also the main component of cement. COS, the main product, is formed by the catalytic oxidization of CS2 with adsorbed “molecular” oxygen over the catalysts’ surfaces. The concentration of adsorbed oxygen over catalysts’ surfaces may be the key factor contributed to the oxidizing activity. It is indicated that CS2 could be catalytically oxidized over atmospheric particles, which induced that this reaction may be another important source of atmospheric COS from CS2.