共查询到15条相似文献,搜索用时 140 毫秒
1.
2.
3.
阴离子表面活性剂亲水亲油平衡值的QSPR研究 总被引:1,自引:0,他引:1
采用分子电性距离矢量(MEDV)表征65个阴离子表面活性剂的分子结构,运用多元线性回归技术,同时采用逐步回归结合统计检测对模型变量进行筛选,建立了阴离子表面活性剂的亲水亲油平衡值(HLB)与MEDV的定量结构.性质关系(QSPR)模型。采用内外双重验证的办法深入分析和检验所得模型稳定性,建模计算值、留一法交互校验预测值和外部样本预测值的复相关系数僻)分别为0.971、0.956和0.958。结果表明:所建QSPR模烈有良好的稳定性和预测能力。该研究结果为预测表面活性剂的亲水亲油平衡值提供了理论依据。 相似文献
4.
5.
6.
利用结构-性质定量关系方法研究了多种结构表面活性剂的亲水亲油平衡(HLB)值,得到了相关性显著(R2=0.986 5,F=991.37,S2=2.499 1)的五参数线性模型。在构建的HLB值模型中,既有反映疏水烷烃链碳原子数目的局部结构描述符(l-NC)以及形状与尺寸的局部拓扑描述符(l-KSI3),还有反映亲水基团离子性质的静电描述符(MPCO)和分子极性本质的极化参数(PP),此外还引入了量子化学描述符(MVC),从本质上揭示了影响表面活性剂亲水亲油平衡的众多结构因素,提高了表面活性剂HLB值预测能力的准确性。结合三次采油用表面活性剂的要求,从表面活性剂分子结构因素的调控出发,提出了驱油用表面活性剂分子设计的依据。 相似文献
7.
阴离子表面活性剂的HLB值与端基和碳原子数的关系 总被引:1,自引:0,他引:1
通过应用Microsoft Office Excel 2003对部分阴离子表面活性剂的HLB值所进行的处理结果发现:阴离子表面活性剂的HLB值随亲油基碳原子数的变化规律很好地满足线性函数Y=ax b这一关系。同时也发现端基不同的表面活性剂亲水基的亲水性越强,其HLB值曲线的截距越大,而其亲油基上每增加一个-CH2-所引起HLB值的改变却相同。 相似文献
8.
9.
10.
11.
12.
优晓辞’范奉艳’黄迎’等 《世界农药》2014,(1):43-48
亲水亲油平衡值(Hydrophile/Lipophile Balance,HLB)是表征表面活性剂性质的重要参数。采用比较分子力场分析(comparative molecular field analysis,CoMFA)方法和比较分子相似性指数分析(comparative similarity indices analysis,CoMSIA)方法,研究了30个烷基酚聚氧乙烯醚系列非离子表面活性剂的三维定量结构与pHLB值的关系。建立的CoMFA模型交叉验证系数为0.705,非交叉验证系数为0.805:CoMSIA模型交叉验证系数为0.685,非交叉验证系数为0.813,都有较好的预侧能力。此外,运用多元线性回归方法建立一种预报硫酸盐类表面活性剂HLB的QSPR模型,模型的复相关系数为0.711。所有选取的测试集和训练集的预报结果较为吻合,说明硫酸盐类表面活性剂HLB值QSPR模型具有良好的预报能力和普适性。 相似文献
13.
Leszek Marszall J. Wade Van Valkenburg 《Journal of the American Oil Chemists' Society》1982,59(2):84-87
The empirical hydrophile-liophile balance (HLB) value of nonionic surfactants is an important parameter used to predict performance
as, e.g., emulsifiers, solubilizers and wetting agents. However, the HLB value is based on an original molecular structure
and does not take into account all the factors affecting the performance of nonionics, such as presence of additives, type
of solvent, temperature, degree of hydration, structural modifications of the surfactant molecule and decomposition of surfactants.
On a performance basis, where these factors come into play, a given nonionic surfactant may exhibit a multiplicity of apparent
HLB values. Accordingly, we recently introduced the term “effective HLB value” which is a performance value which incorporates
into the HLB the parameters listed above. The HLB value thus becomes a variable depending on the physical and chemical conditions
at the time of the measurement. In this work, we investigated the effect of adding glycols and diglycols on the HLB using
3 different methods: cloud point, phenol index and critical micelle concentration (cmc). We found that this type of additive
increases the cloud point, phenol index, cmc and the “effective HLB” of a polyoxyethylated nonionic surfactant. The effectiveness
of the glycols in causing these increases was in the following order; dipropylene glycol > 1,4-butanediol > 1,2-propanediol
> diethylene glycol > ethylene glycol. The solvent effect of glycols and diglycols on the hydrophobic and hydrophilic portions
of the surfactant molecule are discussed. On the hydrocarbon part of the surfactant molecule, the solvents cause a weakening
of the hydrophobic bond and an increase in the cmc. On the polyoxyethylene part of the molecule, the solvent may cause either
an increase or a decrease in the cmc. The effect on the hydro-philic portion is related to hydrogen bonding exhibited by the
additives. The results obtained again suggest that the effective HLB value, which is a measure of the HLB under operative
conditions, may be of greater practical significance than calculated HLB. 相似文献
14.
拓扑指数法研究直链烷基芳基磺酸盐的构效关系 总被引:2,自引:0,他引:2
利用拓扑指数法研究了直链烷基芳基磺酸盐的分子结构与等效烷烃碳数和生物降解性的关系.根据分子结构的特点,用距离矩阵表征分子中原子的连接性,据此建立相应的定量结构性能关系式.计算了25个直链烷基芳基磺酸盐的等效烷烃碳数和19个直链烷基芳基磺酸盐的生物降解性,计算结果表明,计算值与文献值的相关系数分别为0.997 2和0.985 0,其相对误差范围分别为-14.38~0.46及-0.06~0.08. 相似文献
15.
Foam enhancement by short-chain hydrophobe alcohol ethoxylates in light-duty liquids 总被引:2,自引:0,他引:2
Brian D. Condon 《Journal of the American Oil Chemists' Society》1994,71(7):783-787
This study examined linear alcohol ethoxylates as foam-enhancing agents in light-duty liquids. The ethoxylates were formulated
as supplementary surfactants to an anionic main surfactant system. The relationship between ethoxylate structure and performance
was elucidated, comparisons were made between ethoxylates and other recognized foam-enhancing agents, and a representative
light-duty liquid formula was optimized. Performance evaluation focused on manual plate washing capacity but also included
agitation foam volume, surface activity, cloud and clear temperatures, viscosity and grease cutting. Shortchain alcohol ethoxylates
with a high degree of ethoxylation (such as C8 with 70% or 7 moles of ethylene oxide) gave optimum performance that was comparable to or better than acknowledged foam-enhancing
agents. The substitution of an alcohol ethoxylate for a fatty acid ethanolamide in the test formulation resulted in substantially
lower formulation viscosity. 相似文献