纤维素在离子液体中均相酰化反应动力学

以离子液体1-烯丙基-3-甲基咪唑氯盐（AmimCl）为反应媒介,以微晶纤维素为原料,研究了离子液体中纤维素与酸酐均相酰化反应的动力学,通过实验考察了纤维素初始羟基浓度（0.21～0.85 mol·L^-1）及反应温度（353～373 K）对酰化反应速率的影响。结果表明,随着离子液体中纤维素羟基浓度的增大和反应温度的升高,纤维素酰化反应的速率都呈增大趋势。通过实验得到了纤维素均相酰化反应的动力学方程,纤维素乙酐酰化及乙酐、丁酐混合酸酐酰化反应的反应级数均为1,表观活化能分别为19.03 kJ·mol^-1和20.04 kJ·相似文献   

离子液体催化的芳烃氯甲基化反应

Ionic liquids have been used as catalysts for Blanc reaction of toluene. The effects of reaction temperature, reaction time and dosage of the ionic liquid catalyst have been investigated, and the catalytic performance of different ionic liquid catalysts for toluene chloromethylation was also studied. The reaction was found to proceed under mild conditions with excellent conversion （up to 90%） in the absence of Lewis acids. The ionic liquids could be recycled and reused without loss of their catalytic activities.     

单乙醇胺和二乙醇胺甲酸盐离子液体对水、甲醇和乙醇挥发度的影响(英文)

Vapor pressures were measured for six binary systems containing water, ethanol, or methanol with one of the two ionic liquids （ILs） at different component concentrations and temperatures using a quasi-static ebulliometer, with the ILs mono-ethanolammonium formate （[HMEA][HCOO]） and di-ethanolammonium formate （[HDEA][HCOO]）. The vapor pressures of the IL-containing binary systems are well correlated using the NRTL model with an overall average absolute relative deviation （AARD） of 0.0062. The effect of ILs on the vapor pressure depression of sol-vents at 0.050 mole fraction of IL is that [HDEA][HCOO]〉[HMEA][HCOO], and the vapor pressure lowering de-gree follows the order of water〉methanol〉ethanol. Further, the activity coefficients of three solvents （viz. water, ethanol, and methanol） for the binary systems{solvent （1）＋IL （2）}predicted based on the fitted NRTL parameters at T=333.15 K indicate that the two ILs generate a negative deviation from Raoult’s law for water and methanol and a positive deviation for ethanol to a varying degree, change the relative volatility of a solvent. [HMEA][HCOO] may be a promising entrainer to efficiently separate ethanol aqueous solutions by special rectification.     

离子液体[BMIM][DBP]+水+甲醇/乙醇三元工质溶液蒸汽压的测量和预测(英文)

The ionic liquid, 1-butyl-3-methylimidazolium dibutylphosphate ([BMIM][DBP]) was prepared and the vapor pressures of three set of binary solutions H2O(1)/CH3OH(1)/C2H5OH(1) + [BMIM][DBP](2) were measured at different temperature and in the ILs mole fraction range from 0.1 to 0.6 with a static equilibrium apparatus. The measured vapor pressures were correlated with Non-Random Two Liquid (NRTL) activity coefficient model and the average relative deviations (ARD) between experimental and correlated vapor pressures for these binary solutions were 3.19%, 2.42% and 2.95%, respectively. Then, the vapor pressures of two set of ternary solutions H2O(1) + CH3OH(2)/C2H5OH(2) + [BMIM][DBP](3) were measured with an inclined boiling apparatus and further predicted with NRTL activity coefficient model based on the binary interaction parameters coming from fitting the vapor pressures of the binary solutions. The results indicated that the ternary solutions containing [BMIM][DBP] were shown a strong negative deviation from Raoult’s Law when the mole fraction of [BMIM][DBP] was larger than 0.2, which meant that ternary solutions could absorb the refrigerant vapors at the same or below solution temperature. Meanwhile, the average relative deviations between experimental and predicted vapor pressures for ternary solutions were 2.92% and 3.06%, respectively. Consequently, the NRTL active coefficient model used for non-electrolyte solutions was still valid for predicting vapor-liquid equilibrium of binary or ternary solutions containing ILs.     

新型多磺酸基离子液体催化对甲酚与叔丁醇的烷基化反应

The alkylation of p-cresol with tert-butanol(TBA)to 2-tert-butyl-p-cresol(TBC)catalyzed by a novel multiple-SO3H functioned ionic liquid(IL1)was investigated.Meanwhile,the catalytic activity of this novel ionic liquid was compared with other four traditional ionic liquids.The results showed that IL1 has superior catalytic activity to other four traditional ionic liquids with the conversion of 85.3%and selectivity of 95.2%.Also,the reaction conditions were investigated to obtain the optimum conditions.Operational simplicity,small amount of usage,high activity,reusability and selectivity are the key features of this methodology.     

N-烷基-N-甲基咪唑系列离子液体中ZSM-5分子筛催化环已烷氧化反应

Heterogeneous oxidation of cyclohexane by tert-butyl hydroperoxide (TBHP) was carried out over ZSM-5 catalysts with different Si/Al ratios in ionic liquids and organic molecular solvents. Higher yield and selectivity of the desired products were found in ionic liquids than in molecular solvents. The conversion of cyclohexane exhibits a decrease from 15.8% to 10.8% with the increase of Si/Al ratio of the HZSM-5 catalyst, and all the catalysts exhibit good selectivity of monofunctional oxidation products at around 97%. The activity of catalyst is found strongly de-pendent on the alkyl chain length of ionic liquid.     

离子液体催化丁醇与盐酸反应制备丁基氯

The catalytic performance of some quaternary ammonium salts for the liquid phase reaction of butanol and hydrochloric acid at different conditions was studied experimentally and compared with the traditional catalyst （ZnCl2）. The organic ammonium catalysts investigated include ionic liquids N-butyl-N-methyl imidazolium fluoborate （[BMIM][BF4]） and N-butyl-N-methylimidazolium chloride （[BMIM]Cl） as well as hydrochloric salts of N-methylimidazol （[HMIM]Cl）, pyridine （[HPy]Cl） and triethylamine （[HEt3N]Cl）. It is shown that the intrinsic catalytic performance of all organic ammonium salts except [HEt3N]Cl is slightly superior to ZnCl2, while the selectivity of butyl chloride is nearly at the same level around 96%. The conversion of butanol increases slightly with temperature and the catalyst amount added while the variation of selectivity is not obvious. Based on the recycle experiments, the ionic liquids as catalyst for the reaction of butanol and hydrochloric acid can be used more than 5 times, which suggests great potential of using ionic liquids as novel catalyst for such reactions.     

己内酰胺类离子液体的热力学性质(英文)

A series of caprolactam ionic liquids(ILs) containing incorporated halide anions were synthesized.Their physical properties,such as melting points,heats of fusion and heat capacities,were measured by differential scanning calorimeter(DSC).The results indicate that these ionic liquids exhibit proper melting points,high value of heats of fusion,and satisfying heat capacities which are suitable for thermal energy storage applications.     

纤维素在离子液体AmimCl中的均相苯甲酰化反应

酱油渣中可以提取到纤维素等生物资源,但由于纤维素不溶于水和一般溶剂,难以进行衍生化应用,因此常常遭到浪费。而离子液体对纤维素呈现出较好的溶解性,可作为纤维素衍生化的良好溶剂。本文利用提取过油脂和半纤维素的酱油渣为原料进一步提取纤维素,并对以离子液体为溶剂,无催化剂条件下纤维素的均相苯甲酰化进行了研究。重点考察了离子液体种类对均相苯甲酰化的产率和取代率的影响,反应温度、时间、苯甲酰氯与葡萄糖单元摩尔比对均相苯甲酰化的取代率的影响。研究结果发现以离子液体AminCl（1-烯丙基-3甲基咪唑氯盐）为溶剂时有最优的产率。在最优反应条件为温度80℃、时间90min、苯甲酰氯与葡萄糖单元摩尔比4：1时,可得到最高取代率0.72。     

三元铁基离子液体-乙醇-水体系的湿法烟气脱硫性能研究(英文)

Fe-based ionic liquid(Fe-IL) was synthesized by mixing FeCl3?6H2O and 1-butyl-3-methylimidazolium chloride [Bmim]Cl in this paper.The phase diagram of a ternary Fe-IL,ethanol and water system was investigated to construct a ternary desulfurization solution for wet flue gas desulfurization.The effects of flow rate and concen-tration of SO2,reaction temperature,pH and Fe-IL fraction in aqueous desulfurization solution on the desulfuriza-tion efficiency were investigated.The results shows that the best composition of ternary desulfurization solution of Fe-IL,ethanol and water is 1︰1.5︰3 by volume ratio,and pH should be controlled at 2.0.Under such conditions,a desulfurization rate greater than 90% could be obtained.The product of sulfuric acid had inhibition effect on the wet desulfurization process.With applying this new ternary desulfurization solution,not only the catalyst Fe-IL can be recycled and reused,but also the product sulfuric acid can be separated directly from the ternary desulfurization system.     

离子液体中纤维素的均相改性及其产物性能

卤代基团比羟基具有更高的反应活性,因此将含有卤素基团的有机化合物引入到纤维素骨架上可以提高其反应活性,为其后续接枝改性提供更广的应用范围。以氯乙酰氯为酯化剂,离子液体1-丁基-3-甲基咪唑氯盐（［Bmim］Cl）为反应介质,在不加任何催化剂的情况下,直接进行纤维素的均相酯化改性。着重探讨了反应温度、反应时间、酯化剂用量等因素对反应的影响。利用红外光谱（IR）以及核磁共振（NMR）对产物结构进行表征,并研究改性后纤维素在溶剂中的溶解性能。结果表明,离子液体中纤维素的均相酯化改性的最佳工艺条件为：纤维素葡萄糖单元与氯乙酰氯的摩尔比为1∶3,反应温度为常温,反应时间为2 h。此时,改性纤维素取代度为1.36。此外,改性后,纤维素酯易溶于丙酮、二甲基亚砜、四氢呋喃等有机溶剂。     

离子液体中纤维素-甲基丙烯酸羟乙酯的均相聚合

在离子液体介质中利用原子转移自由基聚合方法合成了纤维素一甲基丙烯酸羟乙酯的接枝共聚物,采用甲基丙烯酸羟乙酯单体合成纤维素聚合物,并对聚合物进行结构测定与性质分析。通过FTIR,1H-NMR和GPC对聚合物结构及分子量进行分析,研究了不同溶剂对聚合条件与接枝效率的影响,以及亲水基团的引入聚合物的结构、分子量分布、热稳定性以及在不同溶剂中的形态有何变化。结果表明:在溶剂DMF中进行的反应聚合速率及终止速率均高于在丁酮中进行的反应。纤维素接枝甲基丙烯酸羟乙酯聚合物分子量分布在1.81左右,该聚合物热稳定性较强; 在DMF中呈球状颗粒, 平均直径50nm,在选择性溶剂丙酮中颗粒直径100nm左右     

醋酸丁酸纤维素在离子液体中的均相合成

Cellulose acetate butyrates (CAB) were homogeneously synthesized in an ionic liquid, 1-allyl-3-methyl-imidazolium chloride (AmimC1).By a sequence of first adding butyric anhydride and then acetic anhydride in the cellulose/AmimCl solutions, CAB products with the butyryl contents ranging from 33% to 47%(mass） were obtained.NMR analysis showed that among the three OH groups of the anhydroglucose unit (AGU) of the synthesized CAB, the distribution of the butyryl moieties showed a preference at the C6 position, while the partial degree of substitution of acetyl moieties at the C6 position showed the minimum values.Solubility measurement showed that CAB samples readily dissolved in the common organic solvents, such as methyl ethyl ketone, dichloromethane, and ethyl acetate.     

蔗渣纤维素在离子液体中的溶解与再生

以蔗渣纤维素为原料,在1-烯丙基-3-甲基咪唑氯盐([Amim]Cl)离子液体中,制备出蔗渣纤维素再生膜。通过偏光显微镜观察了蔗渣纤维素的溶解过程,采用红外光谱、扫描电镜、X射线衍射、热重及力学性能等分析测试手段,对蔗渣纤维素及再生膜进行表征,结果表明:未经活化的蔗渣纤维素可快速、直接溶解在离子液体中,再生前后蔗渣纤维素发生了从纤维素Ⅰ到纤维素Ⅱ的晶型转变,蔗渣纤维素再生膜具有致密的结构,热力学稳定性达到292℃,拉伸强度高达144MPa。     

吡啶类离子液体的合成及对纤维素溶解性能的研究

采用一步法合成N-烯丙基吡啶氯盐离子液体([APy]Cl),测定其相溶性和吸水率,利用核磁共振氢谱(1H-NMR)、傅里叶变换红外光谱仪(FT-IR)、质谱(MS)和热分析系统(DSC-TGA)对其化学结构和热稳定性进行分析;并测定对纤维素的溶解能力。结果表明,[APy]Cl为纤维素的优良溶剂,在120℃时对棉浆粕纤维素(聚合度DP=556)的溶解度可达到19.71%,脱脂棉纤维素(DP=1971)可达15.29%。利用FT-IR、X射线衍射仪(XRD)和DSC-TGA对再生前后纤维素进行表征,结果表明该离子液体为纤维素的直接溶剂,可将晶型由Ⅰ型转变为Ⅱ型。     

微波辅助离子液体法对纤维素的均相改性研究

以离子液体1-丁基-3-甲基咪唑氯盐（BMIMCl）为溶剂,采用微波辐射代替常规的加热技术,对纤维素进行均相改性研究。首先进行微波辐射下纤维素在离子液体中的溶解,研究微波辐射温度和溶解时间的影响;其次进行纤维素与氯乙酰氯在微波辅助离子液体中的均相乙酰化研究,利用FT-IR、1H-NMR对聚合物进行了表征,探讨微波辐射功率、反应温度、反应时间和氯乙酰氯用量对纤维素取代度的影响。结果表明,微波加热有利于纤维素溶解和酯化,辐射时间和温度提高均会增加纤维素溶解量,酯化剂用量和微波辐射时间对反应影响较大。     

离子液体法制备再生细菌纤维素纤维

以离子液体(氯化1-甲基-3-正丁基咪唑)溶解高聚合度细菌纤维素(BC),采用湿法纺丝制备再生细菌纤维素(RBC)初生纤维;通过红外光谱分析(FTIR)、广角X射线衍射(WAXD)分析、热失重(TG)分析、扫描电镜( SEM)、单丝强度拉伸等表征了RBC初生纤维的结构和性能.结果表明:该溶剂体系通过10 h的快速搅拌溶...     

纤维素在离子液体1-丁基-3-甲基-咪唑乙酸盐中的溶解性能

研究了纤维素在离子液体1-丁基-3-甲基-咪唑乙酸盐([BMIM] CH3COO)中的溶解性能.结果表明,[ BMIM] CH3COO对天然纤维素有较好的溶解能力,再生得到纤维素膜;随着溶解温度的升高,溶解时间大大缩短.采用红外光谱(FT-IR)、热质量损失分析(TGA)、X-射线衍射(XRD)等对再生前后纤维素进行了...     

离子液体中天然纤维素的溶解研究进展

纤维素是广泛存在的自然资源,普遍应用于石油、医药、电子等行业。但是由于纤维素的本身化学性质使其难以加工。传统的黏胶法与铜氨法由于其生产条件严苛,污染环境,已经不再适合新时代对于绿色化学的要求。近年来,绿色高效的离子液体得到研究开发,为纤维素的发展提供一个新的平台。本文综述了当前纤维素的几种溶解体系及其概况,探讨了各个体系优缺点,并着重介绍了近年来离子液体的研究进展,提出了今后离子液体应用于纤维素的几个方向,以期为今后纤维素溶解及开发更多纤维素材料提供参考。