氢氟烃在离子液体[HMIM][PF_6]中的扩散系数和亨利常数

氢氟烃+离子液体是一种非常有潜力的吸收式制冷循环工质对。利用压力衰减法测量了303.15~343.15K范围内6种氢氟烃(R32、R125、R161、R143a、R1234yf、R152a)在离子液体1-已基-3-甲基咪唑六氟磷酸盐([HMIM][PF_6])中的扩散系数和亨利常数。结果表明:6种氢氟烃在[HMIM][PF_6]中的扩散系数和亨利常数均随着温度的升高而增大。在6种氢氟烃中,因R32在[HMIM][PF_6]中具有较大的溶解度和扩散系数,所以R32+[HMIM][PF_6]较适合作为吸收式制冷循环的工质对。最后,采用Arrhenius方程对6种氢氟烃在[HMIM][PF_6]中的扩散系数和亨利常数进行了关联,计算结果与实验数据的平均绝对相对偏差分别小于2.5%和6.0%。     

R1233zd(E)在[HMIM][PF6]中的溶解度和扩散系数的实验测量和理论计算

R1233zd(E)具有无毒、环保、不可燃等优点,而离子液体具有较宽的液体温度范围和良好的物理化学性质。R1233zd(E)和离子液体相结合可以成为一种优良的吸收式制冷工质对。测量了R1233zd(E)在[HMIM][PF₆]离子液体中的溶解度和扩散系数,温度测量范围为303.2~343.2 K,压力测量范围为23~140 kPa。为了方便工业化应用,采用NRTL方程和Arrhenius方程对实验结果进行了关联,计算结果和实验数据之间的平均偏差和最大偏差分别为2.45%和6.13%。     

离子液体用于燃油萃取脱硫的选择与过程优化

针对基于COSMO-SAC模型分子设计方法的准确性问题,采用离子液体脱硫机理分析和实验的方法对其进行了验证,即对[HMIM] [BF₄]、[HMIM] [PF₆]、[BMIM] [BF₄]、[BMIM] [PF₆]、[EMIM] [BF₄]、[EMIM] [PF₆] 6种离子液体作萃取剂时的脱硫效果进行了脱硫机理的分析和实验的验证,得到的脱硫性能排序与离子液体分子设计结果基本一致,且均认为[HMIM] [PF₆]脱硫率较高。以[HMIM] [PF₆]为萃取剂,通过液相色谱法测定萃取后的液相组成,考察萃取时间、萃取温度、剂油比3个因素对脱硫率、分配系数和选择性系数的影响。通过正交实验设计确定了萃取时间40 min、萃取温度20℃、剂油比2：1为较优操作条件,单次脱硫率为72.74%,四级萃取可将模型油的含硫量由1200 μg·g^-1降至6.98 μg·g^-1,符合国Ⅴ标准。     

离子液体体系用于盐湖卤水提取锂

3种咪唑类离子液体:1-丁基-3-甲基咪唑六氟磷酸盐([C₄mim][PF₆])、1-己基-3-甲基咪唑六氟磷酸盐([C₆mim][PF₆])、1-辛基-3-甲基咪唑六氟磷酸盐([C₈mim][PF₆])被作为绿色溶剂用于盐湖卤水分离镁锂, 建立了以离子液体(ILs)、磷酸三丁酯(TBP)分别为萃取介质和萃取剂的盐湖卤水锂萃取体系, 并与使用传统有机溶剂磺化煤油和氯仿的萃取效果进行了对比。研究发现, 该离子液体体系较使用传统挥发性有机溶剂的萃取体系有更高的萃取率。锂的萃取率随离子液体中烷基碳原子数的减小而增加。详细考察了溶液pH、离子液体浓度、相比对萃取效率的影响, 获得了离子液体体系萃取的最优条件。在最佳萃取条件下, 3种离子液体体系对锂的单级萃取效率均高于80%, 分离系数最高达到100以上。机理研究表明:离子液体体系是以阳离子交换实现对锂的萃取, Li⁺与TBP形成[Li·2TBP]⁺络合物进入有机相。     

离子液体支撑液膜的CO2/CH4分离性能

由于离子液体对CO₂具有较好的溶解选择性,离子液体支撑液膜分离CO₂越来越受到关注。比较了含3种不同阴离子的常规离子液体([bmim][BF₄]、[bmim][PF₆]、[bmim][Tf₂N])作为支撑液膜的液膜相分离CO₂/CH₄的性能,考察了咪唑环上烷基链长对离子液体支撑液膜性能的影响。考虑向离子液体中引入胺基和羧基等亲CO₂基团,制备了1-丁基-3-甲基咪唑丙氨酸离子液体([bmim][β-Ala]),考察了 [bmim][β-Ala]支撑液膜分离CO₂/CH₄的性能,并对在CO₂渗透测试前后的支撑液膜进行了FT-IR分析,发现氨基酸离子液体中的-NH₂和CO₂的较强作用以及该离子液体的高黏性影响了CO₂的透过性,使[Bmim][β-Ala]支撑液膜的CO₂透过率低。     

疏水性离子液体-中性磷氧萃取剂萃取稀土元素的应用

液液萃取广泛应用于稀土元素的分离回收,为了便于相的分离,通常采用疏水性萃取剂。基于液液萃取的特性,通过微波辅助法合成了疏水性离子液体1-丁基-3-甲基咪唑六氟磷酸盐（[BMIM][PF₆]）。分别探究了[BMIM][PF₆]搭配不同中性磷氧萃取剂对稀土元素中Nd³⁺和Pr³⁺的萃取研究。结果表明1-丁基-3-甲基咪唑六氟磷酸盐-三正辛基氧化磷（[BMIM][PF₆]-TOPO）为最适宜萃取体系。在最适宜萃取体系下,探究了时间、温度、pH值、V（A）/V（O）（水相稀土离子/有机相萃取体系）和萃取组分体积比对萃取效率的影响。结果表明：萃取时间为20 min、温度为25℃、pH值=6.0、V（A）/V（O）=1.0、V_[BMIM][PF6]：V_TOPO=1：1,体系对于Nd³⁺的萃取效果最佳,萃取率可达97.8%;萃取时间为25 min、温度为25℃、pH值=6.0、V（A）/V（O）=1.0、V_[BMIM][PF6]：V_TOPO=1：1,体系对于Pr³⁺的萃取效果最佳,萃取率可达94.2%;萃取过程为放热反应,反应焓变分别为ΔH（Nd³⁺）=-38.43 kJ·mol^-1,ΔH（Pr³⁺）=-28.76 kJ·mol^-1。     

咪唑类离子液体对木质纤维预水解液的脱毒

针对燃料乙醇生物炼制过程中抑制物对酵母乙醇发酵的抑制作用,以水洗稀酸蒸汽爆破预处理玉米秸秆得到的预水解液为研究对象,采用新型绿色脱毒技术--离子液体进行萃取脱毒,研究比较了两种咪唑类离子液体[烷基咪唑六氟磷酸盐离子液体[C_nmim][PF₆](n 4,6,8)和烷基咪唑四氟硼酸盐离子液体[C_nmim][BF₄](n 6,8)]对预水解液的萃取性能。结果表明,随着咪唑类离子液体阳离子烷基链长度的增加,离子液体对抑制物的萃取性能下降,具有更强电负性的阴离子为BF₄^-的离子液体比阴离子为PF₆^-的离子液体萃取效率更高。通过比较糖与抑制物的萃取率,最终选择[C₈mim][BF₄]作为预水解液的萃取剂,结果显示其对主要抑制物甲酸、乙酸、5-羟甲基糠醛的萃取率分别为53.22%、47.53%和85.13%,总酚的萃取率为65.05%,而糖的损失率在6%以内。     

胆碱脯氨酸/RTILs支撑液膜的CO2/N2分离性能

选用不同种类的室温型离子液体（RTILs）与胆碱脯氨酸离子液体进行混合分别制得[Choline][Pro]/[EMIm][N（CN）₂]、[Choline][Pro]/[bmim][PF₆]以及[Choline][Pro]/[HMIm][NTf₂]混合离子液体,并将其应用于离子液体支撑液膜（SILMs）。考察操作温度、操作压差、RTILs种类和含量对SILMs分离CO₂/N₂性能的影响。结果表明胆碱脯氨酸/RTILs系列SILMs的CO₂通量在343.3～1936.9 barrer之间变化并且CO₂/N₂选择性为10.3～34.8。对CO₂膜过程内在机制探索表明随着[HMIm][NTf₂]离子液体在混合离子液体中比例的增加,总阻力1/K_m会呈现先降低后升高的趋势。与实验现象中随着[HMIm][NTf₂]离子液体在混合离子液体中比例的增加CO₂先升高后降低相符。     

[Bmim]PF6在甲醇和乙腈中的电导率和黏度研究

测定了298.15K条件下1-丁基-3-甲基咪唑六氟磷酸盐离子液体（[Bmim]PF₆）在甲醇和乙腈中的电导率和黏度,讨论了[Bmim]PF₆/甲醇和[Bmim]PF₆/乙腈体系的溶液性质。结果表明,在0～0.3mol/L的浓度范围内,[Bmim]PF₆/甲醇和[Bmim]PF₆/乙腈体系的电导率随[Bmim]PF₆浓度的增加而增加,并且[Bmim]PF₆在甲醇中的电导率高于在乙腈中的电导率,说明[Bmim]PF₆在甲醇中更容易电离;[Bmim]PF₆/甲醇和[Bmim]PF₆/乙腈体系的摩尔电导率随浓度的增加而降低,采用Kohlrausch公式计算回归了[Bmim]PF₆在甲醇以及乙腈中的无限稀释摩尔电导率（∧_m^w）,其值分别为156.96和153.83s·cm²·mol^-1。由Jones-Dole方程计算回归了[Bmim]PF₆在甲醇和乙腈中黏度B系数,其值分别为0.36813和0.63248,表明[Bmim]PF₆在甲醇中的黏度小于在乙腈中的黏度,这与电导率实验的结果是一致的。     

离子液体催化氯乙酸甲酯合成氯乙酸-2-庚酯的研究

探索了离子液体催化氯乙酸甲酯和2-庚醇的酯交换反应,制备了1-甲基-3-（丙基-3-磺酸基）咪唑对甲苯磺酸盐[MIM-PS][PTSA]、1-甲基-3-（丙基-3-磺酸基）咪唑硫酸氢盐[MIM-PS][HSO₄]、1-丁基-3-甲基咪唑硫酸氢盐[BMIM]HSO₄、N-甲基咪唑磷酸盐[HMIM]H₂PO₄四种离子液体催化剂并用于酯交换反应,通过考察产品氯乙酸-2-庚酯收率,筛选出最佳催化剂[MIM-PS][PTSA]。并用[MIM-PS][PTSA]考察了反应温度、反应时间、催化剂添加量、催化剂循环使用对合成产品收率的影响。结果表明：将氯乙酸甲酯和2-庚醇在100 ℃下,添加5% [MIM-PS][PTSA]催化剂,反应6 h,合成氯乙酸-2-庚酯,收率可达76.3%,离子液体重复使用3次,氯乙酸-2-庚酯收率仍大于初次收率的95%。本实验用离子液体做溶剂或催化剂,反应条件稳定,可循环利用、对环境友好,且产品收率高,为工艺放大提供实验条件参考。     

Densities and Viscosities of 1-butyl-3-methylimidazolium Hexafluorophosphate [bmim][PF6] ＋ CO2 Binary System： Determination and Correlation

A gas-dissolving device was designed and connected to the falling-body viscometer, which was used to determine the viscosities of liquids in our lab before. The equipment can be used to determine the gas composition, the densities and viscosities of the solution at the same time. The densities and viscosities of [bmim][PF6] ＋ CO2 binary system were determined in the temperature range of 313.2 to 413.2 K and pressure range of 5.0 to 25.0 MPa by the equipment. Then the viscosities of [bmim][PF6] ＋ CO2 binary system at constant temperature, constant pressure, and different temperature and pressure were correlated, respectively. For the correlation at different tempera- ture and different t3ressure for different concentration mixtures the average relative deviation ARD is 0.037.     

Determination and Correlation of Solubilities of Four Novel Benzothiazolium Ionic Liquids with PF6^- in Six Alcohols

Four novel benzothiazolium ionic liquids with 6PF- （[C1Bth][PF6], [C4Bth][PF6], [C5Bth][PF6] and [C6Bth][PF6]） were synthesized, and the rang of their melting points were determined between 358.35 K-424.05 K. The relationship of their melting points and the length of the straight alkyl chain on cation reflected‘S’ type ten-dency. Then, the solubilities of the four ionic liquids in six lower alcohols （methanol, ethanol, 1-propanol, 2-propanol, 1-butanol and 2-methyl-1-propanol） were measured in the temperature rang of 253.15-383.15 K at at-mospheric pressure with static analytical method, respectively. It was found that [C6Bth][PF6] in all investigated ionic liquids had the largest solubility in six alcohols and the solubility of [C4Bth][PF6] in methanol was very sensi-tive for temperature in 313.15-333.15 K, which was so-called “temperature-sensitivity”. This feature is of great significance to their application of catalyzing reaction or extraction process, and makes the recovery and reuse of ionic liquids （ILs） become easier. Moreover, the experimental solubility data were correlated with the modified Apelblat equation andλh equation, respectively. It was found that the result of correlation using two divided tem-perature ranges was better than that of using the whole temperature range.     

Application of hydrophobic ionic liquid [Bmmim][PF6] in solvent extraction for oily sludge

In this study, an ionic liquid (IL), 1-butyl-2,3-dimmmethylimidazolium hexafluorophosphate ([Bmmim][PF₆]), was used in combination with a composite solvent of methyl acetate and n-heptane to enhance the oil extraction from oily sludge. The oil recovery increased by approximately 15% compared with that of solvent extraction without [Bmmim][PF₆] at the optimal ratios of IL to sludge and solvents to sludge, which were at 2:5 (M/M) and 4:1 (V/M), respectively. The saturate, aromatic, resin and asphaltene (SARA) analysis revealed that the recovery of resins and asphaltenes was increased by 14% and 38%, respectively, in the solvent extraction with the addition of [Bmmim][PF₆]. [Bmmim][PF₆] maintained a good performance after its reuse four times. The addition of [Bmmim][PF₆] changed the adhesion forces between oil and soil. The IL-assisted solvent extraction procedure followed the pseudo second-order kinetic model, while the unassisted solvent extraction procedure followed the pseudo first-order kinetic model. The results also demonstrated that [Bmmim][PF₆] decreased the solvent consumption by approximately 60% each time. Additionally, [Bmmim][PF₆] can be easily separated. The results suggested that enhancing the solvent extraction with this IL is a promising way to recover oil from oily sludge with a higher oil recovery rate and lower organic solvent consumption than those with the unassisted solvent extraction method.     

Biphenyl Bis [π-cyclopentadienyl ） iron] Dication as an Efficient Cationic Photoinitiator for Epoxy Polymerization

Ferrocenium monocations as photoinitiators for cationic photopolymerization suffer from a limitation of low absorption and low reactivity under high-pressure Hg lamp. Here, a ferrocenium dication salt, biphenyl bis [π-cyclopentadienyl）iron] hexafluorophosphate （[bis（Cp-Fe）-biphenyl] （PF6）2 was synthesized by the ligand exchange reaction between ferrocene and biphenyl. The chemical structure was characterized with FTIR and ^1HNMR. The separation of ferrocenium monocation cyclopentadien-iron-biphenyl hexafluorophosphate （[Cp-Fe-biphenyl] PF6） and dication [bis（Cp-Fe）-biphenyl] （PF6）2 was carried out by column chromatography. The photoactivity of initiating photopolyinerization of epoxide ER14221 was studied as a cationic photoinitiator. [Bis（Cp-Fe）-biphenyl] （PF6）2 can efficiently absorb radiation above 300nm and its photoactivity is higher than that of its monocation.     

Regioselective acylation of pyridoxine catalyzed by immobilized lipase in ionic liquid

The regioselective acylation of pyridoxine catalyzed by immobilized lipase (Candida Antarctica) in 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF₆) has been investigated, and compared with that in acetonitrile (ACN). The acetylation of pyridoxine using acetic anhydride in [BMIM]PF₆ gave comparable conversion of pyridoxine to 5-monoacetyl pyridoxine with considerably higher regioselectivity (93%–95%) than that in ACN (70%–73%). Among the tested parameters, water activity (a_w) and temperature have profound effects on the reaction performances in either [BMIM]PF₆ or ACN. For the reaction in [BMIM]PF₆, higher temperature (50°C–55°C) and lower a_w (<0.01) are preferable conditions to obtain better conversion and regioselectivity. Mass transfer limitation and intrinsic kinetic from the ionic nature of ionic liquids (ILs) may account for a different rate-temperature profile and a lower velocity at lower temperature in [BMIM]PF₆-mediated reaction. Moreover, consecutive batch reactions for enzyme reuse also show that lipase exhibited a much higher thermal stability and better reusability in [BMIM]PF₆ than in ACN, which represents another advantage of ILs as an alternative to traditional solvents beyond green technology.     

[NH2-emim]Br/[Bmim]BF4离子液体中二氧化碳的电化学还原

以2-溴乙胺氢溴酸和N-甲基咪唑盐为原料合成了氨基功能化离子液体1-（2-胺乙基）-3-甲基咪唑溴盐（[NH₂-emim]Br）,用¹H NMR和IR对所制备的离子液体进行了表征,测得25℃下[NH₂-emim]Br的黏度26.691 Pa·s、电导率0.1130 mS·cm^-1,CO₂的溶解饱和度82%（摩尔分数）,将不同含量的[NH₂-emim]Br与[Emim]BF₄、[Bmim]BF₄、[Bmim]PF₆组成二元复合离子液体,并用于CO₂电化学还原研究,循环伏安研究表明,CO₂在[NH₂-emim]Br（0.5%）-[Bmim]BF₄复合离子液体中的还原峰电位较[Bmim]BF₄正移0.4 V,还原峰电流增大9倍,黏度降低为0.08227 Pa·s,电导率增大至1.317 mS·cm^-1,是一种较好的CO₂电化学还原离子液体体系。     

离子液体基工质对的吸收制冷循环性能实验研究

分别对以离子液体1-乙基-3-甲基咪唑磷酸二乙酯[Emim][DEP]为吸收剂的二元工质对[Emim][DEP]+H₂O和以[Emim][DEP]+LiBr为吸收剂的三元工质对LiBr+[Emim][DEP]+H₂O的吸收制冷循环性能进行了实验研究,用于评价这种新型的工质对的制冷性能。实验结果表明,二元工质对[Emim][DEP]+H₂O具有吸收制冷性能,但与LiBr+H₂O工质对相比,其制冷系数较低。当发生温度为90℃、循环水温度为30℃、蒸发温度在10～15℃时,制冷系数仅为0.16～0.28。主要原因是[Emim][DEP]+H₂O工质对具有较高的黏度和较低的热导率,导致吸收器降膜吸收传热系数较低,吸收器吸收水蒸气的能力不足。为了强化其制冷效果,在[Emim][DEP]+H₂O工质溶液中加入少量LiBr水溶液,构成三元工质对LiBr+[Emim][DEP]+H₂O。实验结果表明,三元工质对LiBr+[Emim][DEP]+H₂O的制冷性能优于二元工质对[Emim[DEP]+H₂O,在上述蒸发温度范围内,制冷系数能够达到0.17～ 0.34,并且制冷温度更低。