乙烯亚胺的化学

1883年兰登堡(Landenberg)首先合成了所谓具有三元环的伯胺,但在同年葛勃里耳(Gabriel)从β-溴化乙基胺与氧化银共蒸馏所得乙烯亚胺,误以为乙烯胺CH_2=CHNH_2。直到1900年马克瓦尔德(Marckwald)作了对锰酸盐的稳定性试验,认为不可能是乙烯胺,而应该是乙烯亚胺。乙烯亚胺为三元环中最活泼的化合物,极易开环与醇基、胺基等亲核试剂起反应,本身又易聚合。自1935年以来,就被广泛应用于纺织工业,近年来发展     

加速溶剂萃取-气相色谱-质谱法测定乙烯-乙酸乙烯共聚物制品中的苯乙酮

正乙烯-乙酸乙烯(EVA)树脂是乙烯-乙酸乙烯共聚物,由于在分子链中引入了乙酸乙烯单体,从而降低了结晶度,提高了柔韧性、抗冲击性、填料相溶性和热密封性能,因此被广泛应用在发泡鞋料、玩具、包装膜、热熔胶和电线电缆等领域~([1])。近年来,欧盟非食品类产品快速预警系统(RAPEX)已多次通报意大利、德国和波兰等国家,发现产自中国、马来西亚的玩具(主要是EVA拼图式地垫)和EVA儿童     

乙烯与乙烯工业

乙烯是烯烃同系列中的第一个成员,是产量最大的有机化工产品。本文从乙烯的来源、性质、用途等方面展示了乙烯在石油化学工业中的重要地位;我国乙烯工业的概貌。乙烯工业产品对环境的影响及其对策。     

乙烯与乙烯工业

乙烯是烯烃同系列中的第一个成员，是产量最大的有机化工产品。本文从乙烯的来源、性质，用途方面展示了乙烯在石油化学工业中的重要地位；我国乙烯工业的根貌。乙烯工业产品对环境的影响及其对策。     

偏氟乙烯-三氟乙烯共聚物的分子链结构与多晶型现象

偏氟乙烯-三氟乙烯共聚物(PVDF/TrFE)的合成及物性研究,是改善聚偏氟乙烯(PVDF)压电性的一种尝试。据文献报道,PVDF/TrFE 有明显的铁电性,以及强的压电性     

单茂钪催化乙烯与苯乙烯衍生物共聚合的研究

以(C5Me4Si Me3)Sc(CH2C6H4NMe2-o)2和[Ph3C][B(C6F5)4]组成的单茂钪催化体系,考察了其催化不同取代基团苯乙烯衍生物均聚合以及与乙烯共聚合的性能.结果表明单茂钪催化体系可以催化对甲基苯乙烯和对乙烯苯基二甲基硅烷均聚合,高活性(106g聚合物(mol Sc)-1h-1)地获得高间规聚合物;催化二乙烯基苯和乙烯苯基-1-丁烯聚合会发生不同程度的交联反应.在1.01×105Pa乙烯压力下,单茂钪催化体系分别催化对甲基苯乙烯、对乙烯苯基二甲基硅烷与乙烯与共聚合,获得了组成和分子量可控的乙烯/对甲基苯乙烯、乙烯/对乙烯苯基二甲基硅烷共聚物,共聚合活性高达106g聚合物(mol Sc)-1h-1.通过1H-NMR、13CNMR、GPC和DSC对共聚物组成、结构和热性能进行了分析表征.结果表明,在1.01×105Pa乙烯压力下改变苯乙烯衍生物的用量,共聚物中对甲基苯乙烯或对乙烯苯基二甲基硅烷的摩尔含量可以在8 mol%~55 mol%间调控,共聚物含有间规聚对甲基苯乙烯嵌段或间规聚对乙烯苯基二甲基硅烷嵌段、聚乙烯嵌段和乙烯-苯乙烯衍生物的链接序列,共聚物分子量(Mn)可以在3×104~16×104间调控,共聚物具有约127℃的熔点.     

ZSM-5分子筛催化乙醇脱水制乙烯反应机理

正乙烯是有机化工和石油化工最重要的基础原料。目前,乙烯主要来源于石油裂解。生物质乙醇制乙烯以及高级烃类化合物受到了学术界和工业界的关注~(1–3)。与传统的乙醇脱水制乙烯的氧化铝催化剂相比,沸石分子筛,尤其是ZSM-5或改性ZSM-5,具有更高的乙烯选择性和低温反应活性~(4,5)。乙醇脱水的第一步就是乙烯的生成,随后乙烯的     

过渡金属乙烯齐聚与聚合催化剂研究进展

综述了近年来过渡金属配合物催化乙烯齐聚与聚合的最新进展;介绍了乙烯齐聚或聚合的反应时间、反应温度、乙烯压力、助催化剂用量等反应条件及配体上不同取代基对前过渡金属(铬,锆,钛,钒)和后过渡金属(铁,钴,镍,铜)配合物的催化活性和齐聚或聚合产物的影响;分别以钛和镍配合物催化剂为例,介绍了前过渡金属和后过渡金属催化乙烯齐聚或聚合的机理。     

乙烯控制瓠瓜性别分化的机理研究

植物激素改变瓠瓜的性别是与其花芽分化过程中有“特定两性期”有关.ACC(乙烯前体)和STS(乙烯拮抗剂)能改变“特定两性期”的离体花芽性别分化的方向.STS是通过抑制乙烯的作用,直接促进雌花芽中的雄蕊原基发育、相应地抑制雌蕊原基发育而发挥诱雄作用,由此推论,乙烯是直接抑制雄花芽中的雄蕊原基发育、相应地促进雌蕊原基发育而发挥诱雌作用.乙烯的这种诱雌作用是通过改变同化物向雌雄蕊运转的方向,进而改变雌雄形态分化的方向.     

氧亚甲基连接的聚氧乙烯电解质

<正> 聚氧乙烯(PEO)和锂盐混合后具有聚合物电解质(Polymer electrolyte)的离子导电性,可用于制作高能量密度薄膜固体电池。存在的问题是因聚氧乙烯导电发生在非晶区,而未经改性的聚氧乙烯在室温下结晶度X_c>70％,必须在熔化时才具有良     

Titanium-Catalyzed Hydroaminoalkylation of Ethylene

The first examples of titanium-catalyzed hydroaminoalkylation reactions of ethylene with secondary amines are presented. The reactions can be achieved with various titanium catalysts and they do not require the use of high pressure equipment. In addition, the first solid-state structure of a titanapyrrolidine that is formed by insertion of an alkene into the Ti−C bond of a titanaaziridine is reported.     

离子液体在乙烯/乙烷和乙烯/乙炔分离中的应用

乙烯,作为石油化工行业的龙头原料,其高效回收分离具有重要的战略意义。离子液体作为一种结构可调控的新型绿色溶剂,在乙烯的回收分离中展现出巨大的应用前景。本文总结了近年来离子液体在乙烯/乙烷和乙烯/乙炔分离方面的研究进展,从溶剂吸收、膜吸收和与多孔材料相结合的吸附分离法等角度展开,系统地阐述了常规离子液体、功能化离子液体、聚离子液体等纯组分体系及多组分体系在不同分离方法中的研究现状,展望了离子液体在乙烯回收分离方面的应用前景和发展趋势。     

气相色谱法测定创可贴中环氧乙烷和氯乙醇

将创可贴置于顶空瓶中,在已恒温60℃的烘箱中放置30 min,抽取瓶中气体进样检测环氧乙烷,并通过外标法定量。将创可贴置于密封瓶中,加5 mL浸提液,25℃下浸提24 h后进样检测氯乙醇,并通过外标法定量。气相色谱法检测环氧乙烷的加标回收率为93.1%～97.5%,检出限(3S/D)为0.1μg/g。气相色谱法检测氯乙醇的加标回收率为93.2%～99.3%,检出限(3S/D)为0.05 mg/L。     

Characterization of Ethylene methyl methacrylate and Ethylene butylacrylate Copolymers with Interactive Liquid Chromatography

Summary: Copolymers of ethylene with methyl methacrylate (EMMA) and butyl acrylate (EBA), which are of different average chemical composition and block lengths according to NMR analysis, were analyzed by size exclusion chromatography (SEC), differential scanning calorimetry (DSC), Crystallization Analysis Fractionation (CRYSTAF), and high performance liquid chromatography at high temperature (HT-HPLC). With CRYSTAF and DSC crystallizing fractions were detected only in some samples. HT-HPLC fractionated all the samples irrespective of their crystallinity. Homopolymers, PMMA and PE were also found in the copolymer samples of EMMA. EMMA and EBA were separated in HPLC according to the content of polar comonomer. A linear correlation between the MMA content and elution volume could not be established due to the presence of homopolymers as admixtures. In such a case the average chemical composition obtained by NMR does not correspond to the real chemical composition of the copolymers. Unlike EMMA the EBA samples eluted in single peaks, which was used for evaluation of their chemical composition distribution. The comparison of results obtained by fractionation via CRYSTAF and HT-HPLC clearly demonstrates the advantages of the chromatographic approach to study the chemical heterogeneity of olefin based copolymers.     

乙烯催化转化制备乙二醇反应中TS-1分子筛的失活

采用连续循环反应的方式考察了TS-1分子筛在催化双氧水氧化乙烯制备乙二醇反应中的失活过程.其中,新鲜、反应后和再生的TS-1分子筛采用氮气物理吸附、XRF、SEM、XRD、FT-IR和UV-vis等技术进行表征,反应后分子筛表面的吸附物种分别采用FT-IR、GC-MS和TG-DTA进行定性和定量分析.结果表明,反应过程中TS-1分子筛未发生明显的Ti物种的流失,乙二醇低聚物等大分子有机物在分子筛微孔通道内的聚集而引起的孔道堵塞和活性Ti位点可及度的降低是分子筛部分失活的主要原因.失活后的催化剂可以通过双氧水处理移除其表面吸附的物种而部分再生,而高温焙烧可以彻底清除分子筛孔道内沉积的有机物从而恢复分子筛的催化活性.     

Zirconium Catalyzed Ethylene Oligomerization

A review of the scientific and patent literature on oligomerization of ethylene to linear olefins in the presence of homogenous or heterogeneous zirconium complexes and various aluminum organic compounds has been fulfilled for last twenty-five years. Over these years, a wide range of studies had been conducted for selective oligomerization of ethylene into a narrow fraction of linear α-olefins such as C₄-C₈ and C₆-C₁₀ fractions. During the discussion of these catalytic systems, exceptional attention is also paid to feature works such as the activity of the catalysts and the acquisition of clear liquid product without any trace of polymer, all of which play important roles in the selection of the best technology.     

Bromine-Enhanced Generation and Epoxidation of Ethylene in Tandem CO2 Electrolysis Towards Ethylene Oxide

The indirect electro-epoxidation of ethylene (C₂H₄), produced from CO₂ electroreduction (CO₂R), holds immense promise for CO₂ upcycling to valuable ethylene oxide (EO). However, this process currently has a mediocre Faradaic efficiency (FE) due to sluggish formation and rapid dissociation of active species, as well as reductive deactivation of Cu-based electrocatalysts during the conversion of C₂H₄ to EO and CO₂ to C₂H₄, respectively. Herein, we report a bromine-induced dual-enhancement strategy designed to concurrently promote both C₂H₄-to-EO and CO₂-to-C₂H₄ conversions, thereby improving EO generation, using single-atom Pt on N-doped CNTs (Pt₁/NCNT) and Br⁻-bearing porous Cu₂O as anode and cathode electrocatalysts, respectively. Physicochemical characterizations including synchrotron X-ray absorption, operando infrared spectroscopy, and quasi in situ Raman spectroscopy/electron paramagnetic resonance with theoretical calculations reveal that the favorable Br₂/HBrO generation over Pt₁/NCNT with optimal intermediate binding facilitates C₂H₄-to-EO conversion with a high FE of 92.2 %, and concomitantly, the Br⁻ with strong nucleophilicity protects active Cu⁺ species in Cu₂O effectively for improved CO₂-to-C₂H₄ conversion with a FE of 66.9 % at 800 mA cm⁻², superior to those in the traditional chloride-mediated case. Consequently, a single-pass FE as high as 41.1 % for CO₂-to-EO conversion can be achieved in a tandem system.     

Ethylene oxidation over silver

Ethylene oxidation on silver has been studied at 448 K and oxygen and ethylene ( ) partial pressures of 0.08 and 2×10^–5–0.02 atm, respectively. The initial reaction orders with respect to ethylene in the selective and complete oxidation on silver surface purified by oxygen and hydrogen for =0.001–0.02 atm are close to 0.30–0.35 but upon decreasing to 2×10^–5 atm, they diverge and become equal to 1.7 and 1, respectively.

---

448 , 0.08 ( ) 2×10^–5–0.02 . , 0.0001–0.02 0.30–0.35, 2×10^–5 1.7 1, .

     

Ethylene Epoxidation in Cylindrical Dielectric Barrier Discharge: Effects of Separate Ethylene/Oxygen Feed

The effects of separate C₂H₄/O₂ feed and C₂H₄ feed position on the ethylene epoxidation reaction in an AC cylindrical dielectric barrier discharge reactor were investigated. The highest EO selectivity of 34?% and EO yield of 7.5?%, as well as the lowest power consumption of 1.72?×?10^?16 Ws/molecule of EO produced, were obtained at a C₂H₄ feed position of 0.25, an O₂/C₂H₄ feed molar ratio of 1/4, an applied voltage of 13?kV, an input frequency of 550?Hz, and a total feed flow rate of 75?cm³/min. The results demonstrated, for the first time, that the separate feed of C₂H₄ and O₂ could provide better ethylene epoxidation performance in terms of higher EO selectivity and yield, and lower power consumption, as compared to the mixed feed. All undesired reactions including C₂H₄ cracking, dehydrogenation, oxidation, and coupling reactions are lowered by the ethylene separate feed because of a decrease in opportunity of ethylene molecules to be activated by generated electrons.