共查询到19条相似文献,搜索用时 140 毫秒
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低阶煤温和液化特征分析 总被引:1,自引:0,他引:1
利用管弹反应器考察了霍林郭勒褐煤在温和条件下的液化特征,探讨了温度、溶剂、压力、气氛、催化剂对液化产物分布的影响;分别利用程序升温热解技术和红外光谱分析了液化产物中己烷不溶物的气态烃逸出规律和结构特征;利用凝胶渗透色谱、同步荧光光谱和红外光谱分析了不同反应条件下产物沥青烯和前沥青烯的结构特征。结果表明,实验条件下霍林郭勒煤的起始热解液化温度在350℃左右;随温度的升高,液化转化率增大。较高温度时(450℃)缩聚反应加剧,液化转化率开始减小;溶剂对沥青烯类产物的生成极为重要,提高反应压力和添加催化剂主要促进油气的生成;温和条件下(350、400℃)对霍林郭勒煤的临氢处理,可获得热解反应性较原煤高的液化残渣(己烷不溶物);产物沥青烯和前沥青烯的分子量在液化温度为300和350℃时为最大;随反应温度升高,沥青烯和前沥青烯的芳烃结构特征增强,烷烃结构特征减弱。 相似文献
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利用麦秆制聚氨酯多元醇研究 总被引:4,自引:0,他引:4
以小麦秸秆为原料,在浓硫酸催化作用下以聚乙二醇(PEG400)为液化试剂进行液化,讨论了麦秆纤维粒径、催化剂用量、乙二醇(EG)加入量、反应温度和时间等因素对液化残渣率的影响.结果表明:当纤维为">12目",EG用量为20%,浓硫酸用量为4%,在160℃下反应60min时,所得残渣率最小,为0.8%.羟值、酸值的测试结果和红外分析结果表明,液化过程中羟值逐渐减小,而酸值则呈现先增大后减小的趋势,说明反应后期有酯缩合反应发生.将液化产物与二苯基甲烷二异氰酸酯(MDI)反应可制成泡沫材料,红外光谱证实生成物具有聚氨酯的典型特征.得到的泡沫材料密度为38kg/m3,抗压强度为118kPa,性能优良. 相似文献
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中低温煤焦油重油正庚烷萃余物的反应(甲醛)分离与分析 总被引:1,自引:0,他引:1
以陕北中低温煤焦油重油为原料,采用正庚烷溶剂萃取得到煤焦油正庚烷萃余物(H-CT)并与甲醛反应,通过溶剂萃取法将反应后产物(P)分为:正庚烷可溶物(HS-P)、正庚烷不溶甲苯可溶物(HI-TS-P)、甲苯不溶喹啉可溶物(TI-QS-P)和喹啉不溶物(QI-P)。借助GC-MS、FT-IR、TG-FTIR等分析手段,对P的结构组成进行了表征。结果表明,与H-CT相比,P中TI-QS-P组分和氧原子的含量较多,C/H原子比较高;HS-P、HI-TS-P、TI-QS-P和QI-P的含量分别为11.63%、26.42%、57.08%和4.88%;HS-P和HI-TS-P均以中性组分(以芳烃为主)为主,酸性组分(以酚类为主)含量较少,其余为含O、N、S等杂原子化合物;TI-QS-P富集了羰基、亚甲基桥键及稠环芳香化合物,且含酚羟基及芳环取代物,具有较高的热稳定性。 相似文献
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用核磁共振氢谱和红外光潜跟踪了大庆澄清油芳烃组份在液相炭化早期阶段的结构转变。结果表明,多环芳烃分子在热解初期首先脱去环烷上的氢转成芳环,同时发生烷基侧链C_α—C_β键的断裂,形成HS(正己烷可溶)组份。HS组份进一步反应,经烷基链C_α—C_β键断裂而诱发芳核缩合反应,生成更大的芳核分子,并随反应的深入进行,依次生成TS(正己烷不溶甲苯可溶)、PS(甲苯不溶吡啶可溶)及PI(吡啶不溶)等组份。在HS组份部分地转为TS、PS、PI的同时,自身也进一步发生烷基链的断裂。从而在反应中后期形成的TS、PS、PI也表现出烷基侧链的减少。与此同时,PI在生成和积累过程中,发生了脱氢缩合而成更多环数的中间相组份分子,这可从红外光谱1600cm~(-1)峰强逐渐下降证明。 相似文献
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以十六胺为模板剂,采用水热合成法制备了一系列不同铜负载量的Cu-HMS催化剂,并考察了其对草酸二甲酯加氢制乙二醇反应的催化性能.同时,通过X射线粉末衍射(XRD)、N_2低温吸附脱附、红外光谱(FI-IR)、H_2程序升温还原(H_2-TPR)及透射电镜(TEM)等手段对催化剂进行了系统表征.结果表明,铜负载量对催化剂活性组分的分散性和载体之间的相互作用力影响很大.实验结果表明,以20%铜负载量制备的Cu-HMS催化剂催化性能优势明显.在反应温度为205℃、压力为2.0 MPa、氢酯比为80 mol/mol及液时空速为0.4 h-1的条件下,草酸二甲酯的转化率接近100%,乙二醇的选择性高达98.11%. 相似文献
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David E. Bergbreiter Gaston A. Aguilar 《Journal of polymer science. Part A, Polymer chemistry》1995,33(8):1209-1217
The effects of solvent on the accessibility and reactivity of an ester-bound fluorophore at a functionalized polyethylene-solvent interface have been studied. Fluorophore-labeled polyethylene surfaces were prepared by blending together a small amount of a pyrene esterterminated ethylene oligomer and a host linear low density polyethylene in solution. Films cast from such solutions were then studied by fluorescence spectroscopy to show that a significant number of the entrapped pyrene groups were at the polyethylene-solvent interface and capable of reaction with soluble reagents. Subsequently, transesterification of these ester-bound pyrenes using various sodium alkoxides in alcohol, alcohol-toluene, or alcohol-tetrahydrofuran solvent mixtures was studied by fluorescence and UV-visible spectroscopic analysis of the supernatant. The extent of alcoholysis of such esters was found to be significantly affected by the solvent chosen and by the structure of the alcohol. © 1995 John Wiley & Sons, Inc. 相似文献
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《Arabian Journal of Chemistry》2022,15(7):103903
Effective and efficient hybrid depolymerisation technologies are emerging as high potential sustainable routes with considerable benefits over conventional recycling methods for the achievement of circular economies for plastics. Herein, combined green and fast glycolysis-hydrolysis depolymerization of polyethylene terephthalate (PET) was carried out under microwave irradiation (MW) with excellent efficiencies. In MW assisted glycolysis of PET, the catalytic activity of two deep eutectic solvents (DES) based on (choline chloride-urea (DES 1)) and (choline chloride-thiourea (DES 2)) was evaluated and compared. Optimised glycolysis conditions were determined using Box Behnken Design (BBD) to attain maximum weight loss of PET, low crystallinity and increased carbonyl index of residual PET. DES volume of 4 mL, 5.5–6 mL of ethylene glycol, and 0.5 min MW irradiation time resulted in a prominent rise in PET weight loss and carbonyl index of residual PET. DES 2 showed an improved catalytic activity than that of DES 1 which is associated to its stronger interaction with EG and PET polymer chains during the course of the reaction. Residual PET obtained post glycolysis reaction was further depolymerized using MW assisted hydrolysis in the presence of weakly basic Na2CO3 and EG. Within 3-minute, the proposed sequential depolymerization technologies facilitated ≈99% conversion of PET to terephthalic acid (TPA), monohydroxyethyl terephthalate (MHET), and bis (2-hydroxyethyl) terephthalate (BHET) monomers produced at a yield of 62.79–80.66%, 17.22–34.79% and 0.54–0.59% respectively. Application on post-consumer PET sample also revealed very satisfactory results with 96.77–98.25% PET conversion and 60.98–78.10% yield of TPA. 相似文献
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Tokunaga M Kiyosu J Obora Y Tsuji Y 《Journal of the American Chemical Society》2006,128(13):4481-4486
Kinetic resolution of 4-alkyl-2-aryl-5-oxo-4,5-dihydrooxazole-4-carboxylic acid esters (azlactones 1) were achieved by copper-DTBM-SEGPHOS catalyzed alcoholysis reaction with good selectivity (12 examples). Variation of ee of unreacted substrates 1 and products 2 with conversion was found to follow the theoretical line of zeroth-order kinetic resolution, for which the selectivity profiles and graphical analysis were presented for the first time. The efficiency of resolution in zeroth-order reaction is higher than first-order reaction. For example, the reaction with 1a afforded (S)-1a (99% ee) and (R)-2a (74% ee) at 57% conversion, where the k(rel) values were calculated to be 6.7 as zeroth-order kinetic resolution and 37 as first-order kinetic resolution. 相似文献
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以甲基丙烯酸聚乙二醇单甲醚酯600(MPEGMAA600)、 γ-甲基丙烯酰氧基丙基三甲氧基硅烷(G-570)、马来酸二乙酯(DEM)和2-丙烯酰胺-2-甲基丙磺酸(AMPS)为原料,过硫酸钾 硫酸亚铁为引发剂,合成了G-570/MPEGMAA/DEM/AMPS酯类聚羧酸系减水剂,其结构和组成经傅立叶变换红外光谱(FT-IR)和凝胶色谱(GPC)表征。通过正交实验确定最佳合成工艺为:MPEGMAA与DEM、 AMPS和G-570的摩尔比为1.0:1.0:2.0:0.4,过硫酸钾-硫酸亚铁总质量占聚合单体总质量的0.4%,于45 ℃聚合反应8 h,单体转化率为91.71%,水泥初始净浆流动度为225 mm。通过X-射线衍射(XRD)和热重(TG-DTG)分析对加入该减水剂的硬化水泥石微观结构进行了分析。结果表明:该减水剂链段中含有酯基、氨基、磺酸基、醚键、硅氧键等基团,平均相对分子质量分布集中,峰值大都集中在1.2~1.7万。同时,该减水剂可以延缓24 h内水泥水化。 相似文献
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对近年来催化转化多羟基化合物制备5-羟甲基糠醛、乙二醇、1,2-丙二醇、1,3-丙二醇等高附加值化学品进行了综述. 分析了果糖、葡萄糖、纤维素等不同结构的碳水化合物制5-羟甲基糠醛存在的挑战, 并对相应的解决方法进行了总结. 对于5-羟甲基糠醛的转化, 我们重点讨论了5-羟甲基糠醛选择性氧化制备2,5-二甲酰基呋喃和2,5-呋喃二甲酸以及它们作为聚合单体的潜在应用. 概述了催化氢解纤维素、糖醇、甘油等多羟基化合物制备乙二醇、1,2-丙二醇、1,3-丙二醇等二元醇的方法, 并对可能的机理进行了讨论. 依据近年来多羟基化合物催化选择性转化制备高附加值化学品的研究现状, 对今后的研究热点进行了展望. 相似文献
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Monofunctional compounds (benzoic acid, heptyl alcohol, and 2-butoxy-ethanol) were used to investigate the kinetics of the esterification and the alcoholysis reactions. Carboxylic acids (benzoic acid) are the only catalysts present in the reaction medium. The factors which influence the kinetics of the esterification reaction were studied: the nature of the carboxylic acid (substituents on the benzene ring), the nature of the alcohol, the composition of the reaction medium (alcohol alone or with another solvent, ester, or water). The results point out for an acyl type (AAC2) mechanism. The alcoholysis reaction needs the presence of carboxylic acid as a catalyst to occur significantly. A similar mechanism is proposed for both reactions: nucleophilic attack by the oxygen atom of the alcohol at the ion pair formed by protonation of the acid (esterification reaction) or by protonation of the ester (alcoholysis). 相似文献
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Tadahiro Kiguchi Hiroyuki Aota Akira Matsumoto 《Journal of polymer science. Part A, Polymer chemistry》2003,41(21):3243-3248
As part of our continuing studies concerned with the elucidation of the crosslinking polymerization mechanism leading to interpenetrating polymer network (IPN) formation, in which IPNs consist of both polymethacrylates and polyurethane (PU) networks, this article explores the polyaddition crosslinking reactions of multifunctional poly(methyl methacrylate‐co‐2‐methacryloyloxyethyl isocyanate) [poly(MMA‐co‐MOI)] [MMA/MOI = 90/10] with various diols leading to PU network formation. Thus, the equimolar polyaddition crosslinking reactions of poly(MMA‐co‐MOI) with ethylene glycol (EG), 1,6‐hexane diol, and 1,10‐decane diol (DD) were carried out in N‐methyl pyrrolidone at a 0.25 mol/L isocyanate group concentration at 80 °C. The second‐order rate constants decreased from EG to DD. The deviation of the actual gel point from the theoretical one was smaller from EG to DD. The intrinsic viscosity of resulting prepolymer demonstrated almost no variation with progressing polymerization for the EG system, whereas it gradually increased with conversion for the DD system. Close to the gel point conversion it increased rather drastically for both systems. The swelling ratio of resulting gel was higher from EG to DD. These are discussed mechanistically in terms of the significant occurrence of intramolecular cyclization and intramolecular crosslinking reactions leading to shrinkage of the molecular size. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3243–3248, 2003 相似文献