Liquid-phase synthesis of mercaptans and sulfides in the reaction of hydrogen sulfide with alkylene oxide: Estimating catalyst efficiency

A method for the synthesis of β-hydroxypropyl mercaptans and β-hydroxyalkyl sulfides based on the reaction of liquefied hydrogen sulfide with alkylene oxides is proposed. Our technique allows (1) the use of the maximum possible concentration of hydrogen sulfide in the reaction mixture, (2) the process to be performed within a broad range of temperatures, (3) the use of various catalytic additives, and (4) requires no solvent. Kinetic dependencies of the reaction of hydrogen sulfide with alkylene oxides, particularly propylene oxide, are investigated under conditions that allow the reaction components to exist in the liquefied state. In the case of propylene oxide, an excess in the reaction mixture of two consecutive macroscopic stages is observed: the first macro stage includes the formation of 2-hydroxypropane-1-thiol followed by formation of 1,1′-di(2-hydroxypropane) sulfide at the second stage. Staging the accumulation of mercaptan and sulfide allows us to control the process, directing the reaction toward the quantitative production of either mercaptan or sulfide under certain conditions. For example, the use of an excessive amount of hydrogen sulfide results primarily in the formation of 2-hydroxypropane-1-thiol. In addition, the activity of 14 homogenous and heterogeneous catalysts, including activated carbon, ion-exchange resins, metal oxides, water, and triethylamine, is studied. A principle for evaluating the efficiency of catalytic additives based on our mathematical model of the process is proposed. Triethylamine is found to be the most efficient catalyst, raising the reaction rate by a factor of more than 100; i.e., the reaction time without the catalyst was ～50 h, while in the presence of small amounts of triethylamine, the reaction ceased within a few minutes.     

The synthesis of polymeric sulfides by reaction of dihaloalkanes with sodium sulfide

Several poly(alkylene sulfide)s have been synthesized in excellent yields from reactions of α,ω -dibromo- and/or α,ω-dichloroalkanes with sodium sulfide nonahydrate under reflux conditions. The procedure is general, simple and convenient for the production of various poly(alkylene sulfide)s and the way reaction parameters influence the properties of the polymers formed has been examined.

     

光致变色高分子合成研究进展

综述了6类光致变色高分子(包括聚甲亚胺型、含硫卡巴腙结构型、含偶氮苯型、含含螺结构型、含二芳基乙烯型、苯氧基萘并萘醌型)的研究状况.讨论了光致变色聚合物的合成方法、变色性质、影响聚合物性质的因素,并对光致变色高分子的未来研究重点和方向进行展望.     

聚碳酸亚酯多元醇在涂料中的应用

介绍了新型环保涂料中间体材料──聚碳酸亚酯多元醇的生产合成与应用,揭示了其在水性工业涂料中的功用。介绍了国内研发和生产该材料的企业或单位,对其未来市场需求作了重点说明和分析。     

A new,nonphosgene route to poly(bisphenol a carbonate) by melt‐phase interchange reactions of alkylene diphenyl dicarbonates with bisphenol A

This article describes a new, nonphosgene method for the synthesis of poly(bisphenol A carbonate) (PC). The method involves three steps: the reaction of an aliphatic diol with phenyl chloroformate to form an alkylene diphenyl dicarbonate, the reaction of the alkylene diphenyl dicarbonate with bisphenol A to produce an aromatic–aliphatic polycarbonate, and the thermal treatment of the polycarbonate at 180–210°C under a stream of nitrogen with Ti(OBu)₄ to give PC and a cyclic alkylene carbonate. The method furnished low to moderate molecular masses of PC upon the complete elimination of the aliphatic moieties. The approach may be considered a new method, based on polycarbonate thermochemical degradation, for the synthesis of cyclic aliphatic carbonates. The obtained polymers were characterized by intrinsic viscosity and IR, ¹H‐NMR, and ¹³C‐NMR spectroscopy. The thermal treatment step was conducted in a glass reaction tube at 180–210°C under a stream of nitrogen, and the reaction was completed by heating to 250°C. In the thermal treatment step, semisolid effluents composed of cyclic alkylene carbonates were formed and subsequently eliminated from the reaction mixture. Heating to 250°C under nitrogen or under a dynamic vacuum furnished the pure aromatic PC residue. This intrachange reaction provides a flexible method for the synthesis of polycarbonates with alkylene diols containing two or three methylene groups, from which the pure PC homopolymer can be prepared. The potential of this approach was demonstrated by the successful synthesis of PC homopolymer from five different polycarbonates with a bisphenol A unit linked to 1,2‐propylene, 1,3‐propylene, 2‐methyl‐1,3‐propylene, 2,2‐dimethyl‐1,3‐propylene, and 1,3‐butylene as the alkane chains. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

光致变色聚合物

介绍了用合成、共混等方法提高光致变色材料化学性能与物理性能的途径，比较了不同手段对终端产品质量的影响，阐明了化学合成方法在功能材料发展道路上的巨大潜力。     

聚苯硫醚反应过程中钠盐分离的研究

目前硫化钠法是工业化生产聚苯硫醚的主流方法,使用这一合成方法会生成大量无机钠盐副产品,使得PPS的耐环境性,耐化学腐蚀性以及热性能等方面都会下降.通过考察静置时间和静置次数,研究了在聚苯硫醚反应过程中钠盐分离的方法.通过红外、热分析、钠含量以及灰分的测试对产品进行了表征.结果表明:该方法可在反应过程中将钠盐分离开来,分离后的产品具有优异的热稳定性和较低的灰分.     

Synthesis of oligocarbonate diols and their characterization by MALDI-TOF spectrometry

A method of the synthesis of oligocarbonate diols from five-membered cyclic carbonates and aliphatic diols using azeotropic solvents is presented. The influence of a catalyst and reaction conditions on the alkylene oxide and alkylene carbonate insertion into macrodiol molecules were studied and the reaction mechanism is discussed. The oligomeric products were analyzed by means of MALDI-TOF mass spectrometry. The transesterification reaction between propylene carbonate and diols containing six or more carbon atoms in a molecule carried out in the presence of the coordination catalysts such as tin or zinc carboxylate leads to almost pure oligocarbonate diols.     

合成氨煤气一次脱硫塔的选择

气体中硫化物的脱除是保证煤化工企业合成氨和尿素生产装置长周期稳定运行的关键,是该生产过程控制的重点部位。通过几种常用脱硫塔的分析,对高硫份煤制气生产合成氨,采用二级散堆填料塔,其中一级开一备一的三塔组合脱硫工艺路线,笔者认为虽然保守,但较为合理。     

Polymers with Esters of Phosphoric Acid Units: From Synthesis,Models of Biopolymers to Polymer?Inorganic Hybrids

Syntheses, some properties, and applications of the poly(alkylene phosphate)s prepared either by ring-opening polymerization (ROP) or by polycondensation are described mostly on the basis of the data from our laboratories. The ROP of some cyclic phosphates and H-phosphonates are living and/or controlled process. Transesterification of the products of the reaction of an excess of dimethylphosphonate with glycols leads to polymers with M_n close to 5×10⁴. Poly(alkylene phosphate)s with five or six atoms in repeating units bear resemblance to the main chains of nucleic and teichoic acids. These and similar poly(alkylene phosphate)s with different repeating units were used as liquid membranes for the efficient separation of cations as well as to modify the medium for CaCO₃ crystallization. In this latter process, a diblock copolymer with ionic and nonionic block was used. Poly(alkylene phosphate)s constituted the ionic block and the nonionic block was formed from poly(ethylene glycol); together with CaCO₃ polymer inorganic hybrids were formed.     

气相色谱法与汞量法测定气体中微量COS和H_2S

对测定合成氨净化工序工艺气中硫氧化碳和硫化氢的两种方法即气相色谱法和汞量法进行了介绍 ,并与比色法和碘量法的测定数据进行了比较     

Single‐step solution polymerization of poly(alkylene terephthalate)s: synthesis parameters and polymer characterization

Poly(alkylene terephthalate)s represent one of the most frequently used polymer classes worldwide. Well‐known examples include poly(ethylene terephthalate) (n = 2) and poly(butylene terephthalate) (n = 4). The conventional synthesis method for these polymers is based on melt polycondensation, a two‐stage process performed under harsh conditions that includes the synthesis of an intermediate prepolymer and the presence of a catalyst, which may induce toxicity issues. The present work reports on a straightforward single‐step solution polycondensation method performed under mild conditions and in the absence of a catalyst. A homologous series of poly(alkylene terephthalate)s (n = 5 ? 10) of molar masses up to 20 000 g mol^?1 and dispersity <2.4 was synthesized and characterized thoroughly. Great attention was given to the thermal properties assessment by using state‐of‐the‐art techniques and a highly sensitive prototype technique called rapid heat ? cool DSC. Similar to melt‐synthesized polyesters, a particular odd ? even trend of the thermal properties versus the number of methylene groups within the monomer unit was revealed. To the best of our knowledge, this is the first report covering a single‐step solution‐based polycondensation performed in the absence of a catalyst that results in highly reproducible polyesters possessing unaltered thermal properties compared to polyesters synthesized through industrially applied conventional routes. © 2017 Society of Chemical Industry     

变色结晶釉的研制

通过对变色釉和结晶微的机理的探讨，在硅酸锌结晶釉中加入变色颜料，采用一定的生产工艺得到了一种新型艺术釉－变色结晶釉。     

刚性与柔性连接的骨架型二芳烯聚合物

以二芳基乙烯(二芳烯)为共聚单体之一,通过便捷的合成步骤,合成了两个骨架型二芳烯类聚合物,研究了其溶解性、光致变色能力及抗疲劳性等性质。所得到的两个二芳烯聚合物均具有可逆的光致变色能力和优秀的抗疲劳性。在两个聚合物合成过程中,二芳烯与共聚单元的连接分别采用刚性和柔性两种连接方式,从而得到了具有不同分子量及光谱性质的二芳烯聚合物。     

Synthesis and characterization of poly(ether carbonate)s by melt‐phase interchange reactions of dihydroxy compounds with alkylene and arylene diphenyl dicarbonates containing ether groups

A new method of synthesis of poly(ether carbonate)s based on interchange reactions of dihydroxy compounds with alkylene and arylene diphenyl dicarbonates containing ether group was presented. The diphenyl dicarbonate monomers were prepared from phenyl chloroformate and dihydroxy compounds containing ether group (e.g., diethylene glycol, bis(2‐hydroxyethyl ether) of bisphenol A, and 4,4′‐oxydiphenol). The process consisted of a precondensation step under a stream of dry argon followed by a melt polycondensation at 230 or at 250°C under vacuum. Four series of poly(ether carbonate)s were prepared using this approach. Using alkylene and arylene diphenyl dicarbonate‐containing ether groups as monomers, the polycondensation reaction with dihydroxy compounds led to the formation of poly(ether carbonate)s having inherent viscosity values up to 0.56 dL/g and high thermal stability. The glass transition temperature values of polycarbonates were in the range 7–122°C. The polymers were characterized by inherent viscosity and spectroscopic (Fourier transform infrared spectroscopy and ¹H‐NMR and ¹³C‐NMR) and thermal (differential scanning calorimeteric and thermogravimetric) methods. This approach may permit the use of diphenyl dicarbonates containing other organic functional groups for the synthesis of polycarbonates containing those groups. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Production of alkylene oxide derivatives

Summary In this discussion we have reviewed the production of alkylene oxide derivatives which are becoming increasingly important surfactants. The process has been shown to be comparatively simple although the products are very complex mixtures. The course of the reaction has been indicated for the most important types of products and the reaction variables discussed. Perhaps the only disadvantage of this unit process is the hazardous nature of the alkylene oxides. These can be handled safely however, as proven by the safety record of the current producers.     

Catalytic, asymmetric sulfur ylide-mediated epoxidation of carbonyl compounds: scope, selectivity, and applications in synthesis

The reaction of sulfur ylides with carbonyl compounds to give epoxides is an important synthetic method. This Account charts the recent advances in rendering this process both asymmetric and catalytic. Two catalytic methods have been developed: the first involving the reaction of a sulfide with an alkyl halide in the presence of a base and aldehyde and the second involving the reaction of a sulfide with a diazo compound or diazo precursor in the presence of a metal catalyst and aldehyde. These catalytic methods coupled with suitable chiral sulfides provide a new catalytic asymmetric epoxidation process for the preparation of epoxides. The scope of the two catalytic processes is discussed together with the factors that influence both relative and absolute stereochemistry. The application of these methods in target-orientated synthesis is also reviewed.     

溶胶凝法制备铜镉光色玻璃涂层的研究

用溶胶凝胶法在普通平板玻璃表面上制备了铜镉光色玻璃涂层。样品具有可逆的光色性。X-射线衍射和红外光谱分析表明：铜镉光色玻璃涤层的光色相为CuBrxCl1-x固溶体,结构网络由Si-O-Si、Si-O-B和Si-O-Al健连接而成。     

Photochromic effect of transparent lead-free ferroelectric KSr2Nb5O15 ceramics

Transparent KSr₂Nb₅O₁₅ (KSN) lead-free ferroelectric ceramics have been synthesized via modified pressureless sintering method. A significant photochromic effect was observed for the transparent KSN ceramics prepared without rare-earth dopant modification. The piezoelectric properties depend on the grain orientations were investigated. The optical transmittance of the KSN ceramics is greater than 40% in the wavelength range of 530–800 nm. After NUV irradiation, the absorbance was enhanced by more than 40% in a broad visible range (more than 79%). The absorbance returned to the initial value after a thermal bleaching process. The results of the cycling tests and response experiments showed the stability and saturation of the photochromic effect. In addition, the possible photochromic mechanism of the KSN ceramics is discussed and the photochromic centers are identified. This transparent KSN ceramics exhibits an obvious photochromic effect and is a potential candidate materials for optical data storage and information recording applications.     

宽热处理制度AgX光色玻璃的研制

本文研制了一种K2O-B2O3-Al2O3-SiO2系统AgX光色玻璃。此玻璃具有较宽的热处理制度,在610～670℃和2～8h之间进行热处理,热处理温度和时间对玻璃的光色性质影响不大。所以,可作为大面积无色差的平板光色玻璃材料来进一步研究。