电位滴定法测定乙醇/水混合体系中松香酸的离解常数

采用电位滴定法,在乙醇/水混合溶剂体系(I=0.10 mol/L,KCl)测定了松香酸在不同乙醇含量(V/V总)时的离解常数。结果表明,在试验范围内pKa同乙醇含量的体积分数有良好线性关系,通过外推求得在试验条件下松香酸水溶液中的离解常数pKa为4.937。     

N-甲基四氢咔唑酮的绿色合成工艺初探

以N,N-二甲基甲酰胺作溶剂,四丁基溴化铵作相转移催化剂,碳酸二甲酯作甲基化试剂,由四氢咔唑酮与氢氧化钾反应先合成钾盐,再经甲基化合成了N-甲基四氢咔唑酮。考察了钾盐与碳酸二甲酯的配比、反应时间、溶剂用量、催化剂及催化剂用量等因素对反应收率的影响。较佳合成条件为碳酸二甲酯∶四氢咔唑酮钾盐=2.5∶1,四丁基溴化铵用量为钾盐物质的量的2%,在100℃反应10h,反应摩尔收率可达80%以上。     

N-甲基四氢咔唑类化合物的合成研究

以不同取代的苯肼盐酸盐和不同取代的环己酮为原料,通过三聚氯氰催化的四氢咔唑合成和N甲基保护两步反应,在温和的、环境友好的条件下,高效地合成了6个N-甲基四氢咔唑化合物,产率为70%~88%。并以4-甲基苯肼盐酸盐和环己酮为模型底物,对Fischer吲哚合成法进行优化,建立了以溶剂为乙醇,温度为80℃,三聚氯氰0.5当量,反应时间为2 h为最佳反应条件。目标产物经氢谱1H NMR鉴定。     

溴螨酯的合成

在以甲苯为溶剂回流条件下,4,4'-二溴苯乙醇酸与异丙醇进行酯化合成溴螨酯,考察了不同催化剂、反应时间及溶剂比例对反应收率的影响.在最佳条件下,即在混合催化剂亚磷酸酯/磷酸氢盐的作用下,以甲苯为溶剂,在105℃反应30 h,酯化收率90%,纯度95%以上.     

茶叶中茶多酚浸提工艺中溶剂的选择研究

本论文比较了不同溶剂水、甲醇、乙醇、丙酮及其混合溶剂的不同比例对茶叶中茶多酚的浸提效果;实验结果显示选用乙醇-水溶剂时,浸提率达到了22.4%,浸提效果是最好的。为选择茶多酚的浸提方法提供了实验基础。     

布洛芬-烟酰胺共晶制备及其溶解度测定

采用乙醇-水混合溶剂,对布洛芬-烟酰胺共晶的溶液结晶法制备过程进行了研究,制备样品的PXRD和DSC表征结果证明了通过溶液结晶法大规模制备布洛芬 烟酰胺共晶的可行性。制备过程研究结果表明,当混合溶剂中乙醇与水的体积配比为1.82～7.11时,可以制备出布洛芬-烟酰胺共晶;而且随着乙醇与水体积配比的增大,共晶收率呈现先增大再减小的趋势,当体积配比为2.76时,共晶收率达到最大值(76.31%)。还在不同温度下测定了布洛芬-烟酰胺共晶在不同体积配比乙醇-水混合溶剂中的溶解度,结果表明随着温度和乙醇体积比例的升高,布洛芬-烟酰胺共晶的溶解度增大,最后用 Apelblat方程对溶解度数据进行拟合。     

甘蔗渣在水与四氢萘混合溶剂中的液化工艺优化实验

通过正交试验考察了蔗渣在水与四氢萘混合溶剂中液化过程的5个因素对蔗渣转化率的影响.蔗渣在混合溶剂中的优化工艺为:反应温度270 ℃、反应时间30 min、固液比(蔗渣与溶剂质量比)1:6、碱浸预处理NaOH用量4%、四氢萘用量(占总溶剂质量分数)50%.各因素的影响次序:NaOH用量>反应温度>四氢萘用量>固液比>反应时间.在此工艺条件下,蔗渣转化率可达到97.9%.实验结果表明,四氢萘部分取代液化溶剂中的水,可以有效提高蔗渣液化效率,同时降低反应温度及压力,促进实验操作条件的改善.     

咔唑加氢性能研究

咔唑是一种含氮的芳香杂环化合物,文中以Raney-Ni为催化剂,对咔唑的加氢储氢性能进行了研究。实验发现溶剂、温度、压力及催化剂用量等条件的改变均对咔唑的吸氢过程产生影响。溶剂十氢萘的加入有利于咔唑加氢反应进行;在443—563 K咔唑的加氢量随着温度的上升呈现先增加后减小的趋势,并在523 K达到最大值;在3MPa—6 MPa咔唑的加氢量随压力的增大而增大;催化剂用量的增加在低用量范围内明显影响咔唑的吸氢量,在高用量范围内对咔唑吸氢量的影响不大。在咔唑/十氢萘质量比为1/5.9,523 K,5 MPa和催化剂用量为0.5 g的条件下,咔唑的加氢量达到较佳值0.27 mol。GC-MS分析结果表明:咔唑的加氢产物以四氢咔唑、十二氢咔唑为主,此外还含有少量的六氢咔唑及八氢咔唑。     

维生素B_6和维生素B_6酮的溶解度测定与关联

在室温接近 5 0℃的范围内 ,测定了维生素 B6 和维生素 B6 酮在水、乙醇、乙醇和水混合溶剂中的溶解度 ,实验数据用λh方程关联 ,绝对平均相对误差为 0 .95 % ,结果令人满意     

制药废液无害化处理及制取碱式碳酸锌的研究

论述了四氢咔唑酮制药废液的危害,对比了不同氧化剂处理制药废液的氧化能力及其效果,实验研究了次氯酸钠的用量、反应温度及碳酸钠用量等因素对碱式碳酸锌产品质量的影响,确定了四氢咔唑酮制药废液处理的方法和制取碱式碳酸锌的工艺流程,对于环境保护和资源利用,具有一定的参考价值。     

超临界乙醇萃取咔唑的实验研究

以乙醇为超临界萃取基剂,采用恒容升温法研究了超临界乙醇对煤焦油蒽油组分咔唑的萃取效果,探讨了温度和压力对萃取效果的影响。结果表明,在萃取温度为270-280℃、萃取压力为12MPa左右时,咔唑的溶解度较大、萃取率较高,萃取效果明显;温度和压力对超临界乙醇萃取咔唑影响显著;超临界乙醇萃取单组分咔唑效果较好。     

2-羟基-4'-氯查尔酮的合成

以邻羟基苯甲醛和对氯苯乙酮为原料,乙醇为溶剂,氢氧化钾为催化剂合成了2-羟基-4'-氯查尔酮。通过正交实验研究了原料配比、反应时间及催化剂浓度对反应的影响。碱性催化合成的优化工艺条件为:原料配比n(邻羟基苯甲醛)∶n(对氯苯乙酮)=1.0∶1.3,反应时间为6.0 h,催化剂氢氧化钾的质量百分比浓度为20%(用量为30 mL)。优化工艺条件下的产品收率96.6%。产品经IR光谱分析、元素分析及熔点测定确证。     

Electrochemical synthesis and characterization of polycarbazole

Electroinitiated polymerization of carbazole was achieved in acetonitrile by direct electron transfer via constant potential electrolysis based on anodic peak potentials. The anodic peak potential of carbazole was determined by cyclic voltammetry to be + 1.4V. It has been observed that polymer yield increased with some factors, such as time, monomer concentration, and polymerization potential. Conducting polycarbazole material obtained on a platinum anode electrode was characterized by FT‐IR, TGA, and conductance measurements. The conductivities of samples were measured to be about 10^?3–10^?4 S/cm by the four‐probe method. Temperature‐dependence of electrical resistance values of polycarbazole between 30°–125°C suggest that it can be used as a thermal sensor. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 894–898, 2005     

水及杂质积累对粗蒽溶剂结晶精制咔唑的影响

考察了粗蒽结晶分离过程在溶剂循环使用时二甲苯中杂质和乙醇中水的积累对精制咔唑的影响。结果表明,随着二甲苯循环次数的增加,原料中的主要杂质萘、菲和芴在回收二甲苯中逐渐积累,其中萘的浓度最高可达0.35 mg·ml^-1,滤饼中咔唑的含量降低2.77%（质量）左右,收率降低高达7.05%（质量）。同时,母液中杂质的积累使溶剂回收困难,二甲苯的损失率随着循环次数增加而增加,由单程实验的44.75%（体积）增加到循环3次时的79.17%（体积）。原料中的水分随着溶剂循环在回收溶剂中逐渐积累,循环使用3次后,乙醇的含水量高达6.65%（体积）。乙醇含水量在0～12%（体积）之间时,咔唑纯度在98%（质量）以上。含水量在0～6%（体积）时,咔唑的相对结晶度随含水量增加从45.67 %降到40.79 %;含水量为9%和12%时,相对结晶度分别为48.85% 和48.52%。     

水-乙醇体系对双极膜中间界面层的影响

选取Neosepta BP-1,Fumasep FBM,CJ-BPM三种商业标准双极膜作为研究对象,以水-乙醇为研究体系,通过改变不同乙醇含量,测定双极膜的交流阻抗谱,并且对双极膜的耐溶剂性能进行评价,结果表明BP-1具有良好的耐溶剂性,FBM,CJ-BPM耐溶剂性相对较弱;水解离现象发生在LiCl水-乙醇混合溶液中,随着乙醇含量的增加,双极膜的阻值增加,而水解离程度降低。这种现象可以解释为醇解离能力要远远小于水解离能力,因此乙醇的存在使得中间界面层区域的水浓度降低,进而降低了水解离程度;通过简化算法计算出了不同乙醇含量下,BP-1,FBM的中间界面层厚度,更直观地看出乙醇对双极膜水解离性能的影响。     

FTIR-ATR measurements of the ionization extent of acrylic acid within copolymerized methacrylated dextran/acrylic acid networks and its relation with pH/salt concentration-induced equilibrium swelling

In this study, dextran hydrogels were obtained by free radical copolymerization of methacrylated dextran with acrylic acid (AAc) in aqueous solution. The fractions of dissociation of AAc units within hydrogel in response to changes in pH and ionic strength of external aqueous solution were determined by FTIR-ATR spectroscopy. The influence of small ion concentration within hydrogel on the dissociation constant of AAc follows the Debye-Hückel behavior. Based on the results from the FTIR-ATR measurements, the total ion concentration difference inside and outside the hydrogel was determined according to the Donnan equilibrium theory, taking account of the counterion condensation effect quantitatively. The swelling response of hydrogels to changes in external pH and ionic strength was governed mainly by the ionic osmotic pressure due to the accumulation of diffusible ions within hydrogels. The energy balance between the osmotic and elastic retractile responses indicates the non-Gaussian behavior of elastically effective subchains with increasing swelling.     

Conductometric investigations on lanthanum soap solutions

The critical micelle concentration (CMC), degree of dissociation and dissociation constant of lanthanum caprate in benzene-methanol mixtures of varying composition were determined using conductometric measurements. The results show that the soap behaves as a weak electrolyte in these solutions below the CMC. The value of the CMC (0.0027 M) was found to be independent of the solvent composition but increases with the addition of dye.     

Conductance behavior of aqueous solutions of barium,strontium, and nickel soaps

The critical micelle concentration of aqueous solutions of barium, strontium, and nickel soaps was determined by conductivity measurements. The conductance behavior of soap solutions at various temperatures is exhibited by the equation where A and B are constants and C is the concentration of soap in g moles/liter. The values of constant A were found to vary with temperature, whereas those of B were independent of temperature. Kraus and Bray’s type expression was used to evaluate molecular conductance at infinite dilution, dissociation constant K., and heat of dissociation. The results confirm that the critical micelle concentration remains unaffected by temperature in the range 35–50 C.     

Effect of ethanol on the Polarographic Behaviour of Thio-lactic Acid

The polarographic behaviour of thio-lactic acid (RSH) at d.m.e. has been investigated in the presence of KNO₃ and in different water-ethanol (0—50% by volume) mixtures at 30.0 ± 0.2°C. A solution of 0.001% Triton X–100 was used as maximum suppressor. The effect of pH, concentration, temperature, drop time and solvent composition on the characteristics and mechanism of the electrode reaction have been studied in detail. The wave was diffusion controlled, reversible one electron and proportional to RSH concentration in different ethanolic media. The anodic wave of RSH at d.m.e. does not correspond to the formation of RSSR, but to a mercury compound RSHg. The diffusion current (i_d) decreases with increasing concentration of ethanol and is proportional to the square root of viscosity of the medium. The value of E_1/2 shifts towards more negative potentials and the values of the dissociation constant decrease with increasing ethanol concentration. The linearity of i_d with RSH concentration provides a rapid and precise method for the determination of RSH down to 0.03 mM.