吡啶基离子液体[C_6py][DCA]热力学性质及利用新E?tv?s方程预测其表面张力

制备了吡啶类离子液体N-己基吡啶二氰胺盐[C_6py][DCA],并用核磁共振氢谱(~1H NMR)、核磁共振碳谱(~(13)C NMR)、差热扫描量热(DSC)、傅里叶变换红外(FT-IR)光谱对其进行表征。在288.15–338.15 K温度范围内,采用标准加入法,测定其密度(ρ)、表面张力(γ)和折光率(n_D)。在测得的实验数据的基础上,得到了离子液体[C_6py][DCA]的分子体积(V_m)、表面能(E_a)、摩尔极化度(R_m)和极化率(α_p)。结果显示E_a、R_m和α_p几乎不随温度的变化而发生改变。本文还提出了摩尔表面Gibbs自由能(g_s)的概念,并改进了E?tv?s方程。同时还计算了gs、临界温度(T_c)和E?tv?s方程经验参数(kE),并预测了离子液体[C_6py][DCA]的表面张力,预测值与实验值具有较好的一致性。     

1-甲氧基乙基-3-甲基咪唑甘氨酸离子液体的物理化学性质的研究

由于氨基酸基的独特性质,我们以甘氨酸作为阴离子,醚基咪唑基团作为阳离子合成了一种新型离子液体1-甲氧乙基-3-甲基咪唑甘氨酸[MOEMIM][Gly],并经过核磁共振氢谱、核磁共振碳谱和差示扫描量热进行表征。由于离子液体和水之间形成氢键导致传统的方法不能去除水的影响,所以在实验测定中,选用标准加入法在温度范围为298.15–338.15 K,每隔5 K测定离子液体[MOEMIM][Gly]的密度和表面张力。利用密度数据,计算得到离子液体[MOEMIM][Gly]的摩尔体积,并且摩尔体积随着温度的升高而增加,同时得到了热膨胀系数。根据离子液体[MOEMIM][Gly]的摩尔表面Gibbs自由能,改进了传统的Eötvös经验方程,使得方程具有更明确的物理意义,即截距C₀代表摩尔表面焓,它是一个与温度无关的常数,斜率则为摩尔表面熵,这表明改进的Eötvös方程不仅是一个经验方程,而且还是严格的热力学方程。另外,结合摩尔表面Gibbs自由能和改进的Eötvös方程,估算了离子液体的[MOEMIM][Gly]的表面张力,并与实验值进行比较,发现两者很好的一致。     

1-甲氧基乙基-3-甲基咪唑甘氨酸离子液体的物理化学性质的研究（英文）

由于氨基酸基的独特性质,我们以甘氨酸作为阴离子,醚基咪唑基团作为阳离子合成了一种新型离子液体1-甲氧乙基-3-甲基咪唑甘氨酸[MOEMIM][Gly],并经过核磁共振氢谱、核磁共振碳谱和差示扫描量热进行表征。由于离子液体和水之间形成氢键导致传统的方法不能去除水的影响,所以在实验测定中,选用标准加入法在温度范围为298.15–338.15K,每隔5 K测定离子液体[MOEMIM][Gly]的密度和表面张力。利用密度数据,计算得到离子液体[MOEMIM][Gly]的摩尔体积,并且摩尔体积随着温度的升高而增加,同时得到了热膨胀系数。根据离子液体[MOEMIM][Gly]的摩尔表面Gibbs自由能,改进了传统的E?tv?s经验方程,使得方程具有更明确的物理意义,即截距C0代表摩尔表面焓,它是一个与温度无关的常数,斜率则为摩尔表面熵,这表明改进的E?tv?s方程不仅是一个经验方程,而且还是严格的热力学方程。另外,结合摩尔表面Gibbs自由能和改进的E?tv?s方程,估算了离子液体的[MOEMIM][Gly]的表面张力,并与实验值进行比较,发现两者很好的一致。     

醋酸离子液体[C2mim][OAc]水溶液的摩尔表面Gibbs自由能

在288.15-318.15 K温度范围内测定了不同浓度离子液体1-乙基-3-甲基咪唑醋酸盐([C₂mim][OAc])水溶液的表面张力和密度;在改进李以圭等人的溶液表面张力模型基础上,提出摩尔表面Gibbs自由能新概念,建立了摩尔表面Gibbs自由能随溶液浓度变化的线性经验方程,利用这个经验方程估算了[C₂mim][OAc]水溶液的摩尔表面Gibbs自由能,并进一步预测了该溶液的表面张力,其预测值与相应的表面张力实验值高度相关并非常相似。由此可见,摩尔表面Gibbs自由能与等张比容极其类似,可能成为预测离子液体及其溶液性质的一种新的半经验方法。在指定溶液浓度下,根据溶液的摩尔表面Gibbs自由能随温度呈线性变化的规律,得到了新的Eötvös方程,与传统的Eötvös方程相比,新Eötvös方程的每一个参数都有明确的物理意义:斜率的负值是摩尔表面熵,截距是摩尔表面焓,在指定浓度的溶液中摩尔表面焓几乎不随温度变化。     

离子液体[BMim]BF4对SDS水溶液表面活性和聚集能力的促进

采用表面张力测定法和核磁共振谱等方法研究了阴离子表面活性剂十二烷基硫酸钠(SDS)在水溶性室温离子液体[BMim]BF4/水混合溶剂中的表面性质及聚集行为, 发现极少量[BMim]BF4的介入就可以显著降低SDS的临界胶束浓度, 提高体系的表面活性; 且[BMim]BF4在混合溶剂中所占的摩尔分数(x1)在一定范围内(0相似文献   

离子液体[bmim]Cl/AlCl_3催化5-氰基吲哚酰化反应

5-氰基吲哚与4-氯丁酰氯之间的傅-克酰化反应使用路易斯酸之类的催化剂(如AlCl3、FeCl3),反应产物复杂,无法分离出期望的产物5-氰基-3-(4-氯丁酰基)吲哚。在离子液体[bmim]Cl/AlCl3中,进行5-氰基吲哚与4-氯丁酰氯间的傅-克酰化反应,则反应的主产物是5-氰基-3-(4-氯丁酰基)吲哚,产物结构通过质谱与核磁共振氢谱表征。考察了[bmim]Cl/AlCl3中AlCl3与[bmim]Cl间的摩尔比以及[bmim]Cl/AlCl3与5-氰基吲哚的摩尔比对该酰化反应的影响。结果表明,当n(AlCl3)∶n([bmim]Cl)=2.5∶1,n([bmim]Cl/AlCl3)∶n(5-氰基吲哚)=2∶1,室温下反应24 h,最大产率71.7%。     

[Amim]Cl/ZnCl_2离子液体脱除燃料油中碱性氮化物

合成了金属基离子液体[Amim]Cl/Zn Cl2,采用红外光谱对其结构和酸性进行表征,并以碱性氮含量高达0.52%(质量分数)的抚顺页岩油柴油馏分为原料考察其脱氮性能。结果表明,在反应温度30℃、剂油质量比1∶7、反应时间20 min、静置时间2 h的条件下,[Amim]Cl/Zn Cl2对柴油馏分中碱性氮化物的脱除率可达83.78%,且该离子液体经回收重复使用四次后,碱氮脱除率仍能达到52%。     

纤维素在离子液体[AMMor]Cl/[AMIM]Cl混合溶剂中的溶解性能

研究了纤维素在混配离子液体N-甲基-N-烯丙基吗啉氯盐[AMMor]Cl/3-甲基-1-烯丙基咪唑氯盐[AMIM]Cl中的溶解性能, 结果表明, [AMMor]Cl/[AMIM]Cl混配溶剂能有效溶解天然纤维素, 且在相同条件下, 溶解能力要优于离子液体[AMIM]Cl; 随着溶解温度的升高, 溶解时间大大缩短. 利用FTIR, XRD和TGA方法分析了再生纤维素的化学结构和热稳定性, 结果表明, 未经活化的纤维素可直接溶于[AMMor]Cl/[AMIM]Cl而不发生其它衍生化反应, 且天然纤维素在该溶剂体系中纤维素聚合度下降较小.     

锌基离子液体BMIZn2Cl5的性质研究

合成了对水和空气均稳定的锌基离子液体五氯化二锌-1-甲基-3-丁基咪唑(BMIZn2Cl5). 在313.15～343.15 K温度范围内, 测定了离子液体BMIZn2Cl5的密度和表面张力. 拟合并估算了BMIZn2Cl5的恒压热胀系数和表面熵, 并根据Glasser理论和离子液体的空隙模型, 讨论了BMIZn2Cl5的热力学性质, 估算出其晶格能和标准熵 , 计算了离子液体的恒压热胀系数α, 与实验值基本一致, 说明了空隙模型的合理性. 并利用Kabo和Rebelo的方法估算了锌基离子液体BMIZn2Cl5的正常沸点, 蒸气压, 汽化焓( )等性质参数.     

离子液体[C2mim][GaCl4]的溶解热研究

在干燥氩气氛下, 用等摩尔的高纯无水GaCl3和[C2mim][Cl](氯化1-甲基-3-乙基咪唑)直接搅拌混合, 制备了淡黄色透明的的离子液体[C2mim][GaCl4] (1-ethyl-3-methylimidazolium chlorogallate) . 在298.15 K下, 利用具有恒温环境的溶解反应热量计, 测定了这种离子液体的不同浓度摩尔溶解焓 . 针对[C2mim][GaCl4]溶解于水后即分解的特点, 在Pitzer电解质溶液理论基础上, 提出了确定这种离子液体标准摩尔溶解焓的新方法, 得到了[C2mim][GaCl4]在水中的标准摩尔溶解焓, ＝－132 kJ•mol－1, 以及Pitzer焓参数组合: ＝－0.1373076和 ＝0.3484209. 借助热力学循环和Glasser离子液体晶格能理论, 用Ga3＋, Cl－和[C2mim]—的离子水化焓数据以及本文得到的[C2mim][GaCl4]标准摩尔溶解焓, 估算了配离子4Cl－(g)解离成Ga3＋(g)和4Cl－(g)的解离焓ΔHdis([GaCl4]-)≈5855 kJ•mol－1. 这个结果揭示了离子液体[C2mim][GaCl4]的标准摩尔溶解焓绝对值并不很大的原因, 即是很大的离子水化焓被很大的[GaCl4]－(g)的解离焓相互抵消了.     

Pitzer方程应用于离子液体[Cnmim][H2PO4](n= 3, 4, 5, 6)溶解焓研究

在298.15 K下,利用等温环境溶解反应热量计,测定了离子液体[C_nmim][H₂PO₄] (n= 3, 4, 5, 6) (1-烷基-3-甲基咪唑磷酸盐)在水中不同浓度的摩尔溶解热(Δ_solH_m),根据Pitzer电解质溶液理论计算得到了标准摩尔溶解焓(Δ_solH_m⁰)和Pitzer焓参数：β_MX^(0)L, β_MX^(1)L,和C^ϕL,并计算了表观相对摩尔焓。通过推导讨论,得到了离子液体[C_nmim][H₂PO₄](n= 3, 4, 5, 6)同系物每摩尔亚甲基对标准摩尔溶解焓的贡献。     

Liquid crystalline semifluorinated ionic dendrimers

Poly(propyleneimine) [PPI-(NH₂) _n ] and poly(amidoamine) [PAMAM-(NH₂) _n ] dendrimers with n = 4, 8, 16, 32 and 64, have been functionalized with a semifluorinated carboxylic acid [CF₃(CF₂)₇CH₂CH₂COOH] on the surface. The thermal and liquid crystal properties of the resulting ionic dendrimers have been studied by polarized optical microscopy (POM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). All dendrimers show a smectic A (SmA) mesophase, except that derived from the fifth generation of PPI, which displays a columnar mesophase. The mesomorphic behaviour of the dendrimers is attributed to the formation of ionic bonds and to the microsegregation of the dendritic branches and the fluorinated peripheral chains.     

Asymmetric hydroboration of [E]- and [Z]-2-methoxy-2-butenes. Synthesis of (−)-[2R,3R]-butane-2,3-diol in >97% ee

Asymmetric hydroboration of [E]- and [Z]-2-methoxy-2-butene, using (−)-diisopinocampheylborane at −25°C in THF solvent, followed by oxidation using H₂O₂/NaOH, gave (−)-[2R,3R]- and (+)-[2R,3S]-3-methoxy-2-butanols in >97 and 90% ee, respectively. (−)-[2R,3R]-3-Methoxy-2-butanol was converted to (−)-[2R,3R]-butane-2,3-diol (>97% ee, in an overall yield of 65%).     

Dibenzo[b, e]-7,7,8,8-tetraneopentyl- and dibenzo[b, e]-7,7,8,8-tetraisopropyl-7,8-disilabicyclo[2.2.2]octa-2,5-dienes: interaction with tetracyanoethylene and transition metal chlorides

Dibenzo[b,e]-7,7,8,8-tetraalkyl-7,8-disilabicyclo[2.2.2]octa-2,5-dienes (1: R = ^tBuCH₂; 2: R = ⁱPr) were prepared by the reaction of ClR₂SiSiR₂Cl with lithium anthracenide in 1,2-dimethoxyethane (DME) at room temperature. The structure of 1 was determined by X-ray crystallography. Crystal data for 1: monoclinic, rC2/c, A = 12.941(2), B = 14.601(1), C = 35.109(6) Å, β = 94.957(7)°, V = 6609(2) ų, Z= 8, R = 0.048, R_w = 0.053 for 4037 reflections. Compounds 1 and 2 show the bathochromic shift of ¹L_a and ¹L_b bands in UV spectra and exhibit considerably low oxidation potentials due to effective σ-π conjugation. Compounds 1 and 2 form charge-transfer complexes with tetracyanoethylene (TCNE). In the case of 1, the charge-transfer complex (1: TCNE = 2: 1) could be isolated as crystals and the structure was determined by X-ray crystallography. Crystal data for the 1-TCNE complex: monoclinic, C2/c, A= 10.267(2), b = 36.077(4), C = 20.022(4) Å, β = 100.680(8)°, V = 7288(2) ų, Z = 4, R = 0.045, R_w = 0.077 for 4120 reflections. The action of transition metal chlorides on 2 resulted in [4+2] cycloreversion to form ClⁱPr₂SiSiⁱPr₂Cl and anthracene.     

Baeyer-Villiger Oxidation of Cyclic Ketones Catalyzed by Amino Acid Ionic Liquids

A series of amino-acid-based ionic liquids was synthesized via one-step protonation of the corresponding L-amino acid by utilizing an array of proton sources. The catalytic activity of the amino-acid-based ionic liquids for the Baeyer-Villiger oxidation of cyclic ketones was investigated using cyclopentanone as a model cycloketone. The proline-based ionic liquid [ProH]CF₃SO₃ was shown to exhibit the best catalytic activity. The reaction condition was optimized to give the following reagent ratio of n(cyclopentanone):n(catalyst):n(H₂O₂)=1:0.06:4, 60℃ and 6 h. Under the optimum conditions, the conversion of cyclopentanone was 96.57% and the selectivity for δ-valerolactone was 73.01%. The catalytic activity was shown to be constant after 4 cycles. A simple treatment was allowed for the recover and the reuse of [ProH]CF₃SO₃. The successful utilization of [ProH]CF₃SO₃ to catalyze a host of cyclic ketones via Baeyer-Villiger oxidation clearly demonstrated the capacity of [ProH]CF₃SO₃ to tolerate variation in the substrate.     

[C_2mim][Ala]丙氨酸离子液体水溶液粘滞流动的活化参数

在288.15-328.15 K温度范围内,测量了不同浓度的氨基酸离子液体[C_2mim][Ala]水溶液的密度和粘度,根据J ones-Dole方程得到了较大正值的粘度B系数并且dB/dT0。借助Feakins理论,计算了溶质对溶液粘滞流动活化自由能贡献Δμ_2~(≠0),根据Δμ_2~(≠0)随温度的线性变化,进而得到流动活化熵ΔS_2~(≠0)和活化焓ΔH_2~(≠0);在E yring液体粘度的过渡态理论基础上,提出了预测离子液体[C_2mim][Ala]水溶液粘度的半经验新方法,其预测值与相应的实验值很好的一致。     

Asymmetric transfer hydrogenation of ferrocenyl ketones: a new simple route to chiral ferrocenyl alcohols

The asymmetric transfer hydrogenation (ATH) of ferrocenyl ketones, such as FcC(O)CH₂Y [Fc = ferrocenyl, Y = H (1a), CH₃ (1b), Cl (1c) or N₃ (1d)] has been carried out using the Noyori/Ikariya catalysts [(−)-(1R,2S)-ephedrine] or N-tosyl-(1R,2R)-diphenylethylenediamine [(R,R)-TsDPEN] as chiral ligands combined with [RuCl₂(η⁶-benzene)]₂ and 2-PrOH or HCO₂H–Et₃N as the hydrogen sources, respectively. The best results were achieved with the [(R,R)-TsDPEN–Ru^IIHCO₂H–Et₃N] catalytic system, which produced the ferrocenylalcohols (R)-2a, (R)-2c, and (R)-2d in good yields and excellent enantiomeric excesses (>98% ee).     

Copper(I) coordination compounds with two bidentate chelating pyrazole ligands. X-ray crystal structures of DI-μ-chloro-bis[[N,N-bis(1- pyrazolylmethyl)aminoethane]copper(I)] and [bis(N,N-bis(1-pyrazolylmethyl)aminoethane]copper(I) triflate

The pyrazole derivatives of aminoethane N,N-bis(3,5-dimethyl-1-pyrazolyl- methyl)aminoethane (aebd) and N,N-bis(1-pyrazolylmethyl)aminoethane (aebp) form co- ordination compounds with copper(I) of stoichiometry [Cu(L)X], with X = Cl, Br, I and SCN, and [Cu(L)₂X], with X = CF₃SO₃ and BF₄. The ligands chelate in a bidentate manner, with only the pyrazole groups coordinating. The crystal structures of two representative examples have been determined: [Cu(aebp)Cl]₂ is triclinic, space group P , with a = 8.711(2), b = 9.351(1) and c = 9.528(1) Å, = 68.57(1)°, β = 61.47(1)° and γ = 77.82(1)°, and Z = 2. Standard least-squares refinement gave R = 0.029 (R_w = 0.038) for 1804 reflections. [Cu(aebp)₂]CF₃SO₃ is monoclinic, space group P2₁/n, with a = 13.352(5), b = 14.663(3) and c = 15.752(4) Å, β = 117.49(3)°, and Z = 4. Standard least-squares refinement gave R = 0.029 (R_w = 0.032) for 1786 reflections. In both cases the copper environment is slightly-distorted tetrahedral. The chloride compound is dimeric with one ligand molecule (Cu---N distances of 2.011(2) and 2.047(2) Å) and two bridging chlorides per copper (Cu---Cl distances of 2.3874(8) and 2.4094(8) Å). With the non- coordinating triflate anion, a monomeric compound with two ligand molecules per copper was obtained (Cu---N distances of 2.018(4), 2.028(4), 2.049(4) and 2.050(4) Å).