可裂解的表面活性剂(英)(待续)

可裂解的表面活性剂值得关注有几方面的原因。首先,弱键联接的表面活性剂分子结构迎合了改善两亲性物质生物降解能力的发展趋势。裂解可以被酶催化,其生物降解作用可能与污水处理的一般发机理相符合。另外,这些表面活性剂也可以妥,例如,用酸、碱、此一（ＵＶ）、热或臭氧诱发降解反应,对酸、碱不稳定的表面活性剂已引起特别关注,因为在初始步骤所需的稳定性与其在后续步骤中应易裂解并不冲突。综述了制可裂解性表面活性剂的主     

Ester-based surfactants: Are they stable enough?

Surfactants with an ester bond connecting the polar headgroup and the hydrophobic tail are common. They are easy to synthesize, they can often be made from natural raw materials and their biodegradation profile is generally good, partly due to lipase or esterase catalyzed breakdown of the ester bond in sewage plants. A labile ester bond in the molecule may cause problems, however. Surfactants are often formulated at relatively high pH and it is important that they remain intact for a given period of time. In this article we discuss alkaline hydrolysis of different types of ester-based surfactants—cationic, anionic and nonionic—and also of surfactant mixtures. We show that the ester bond in a surfactant has a different hydrolysis pattern than ester bonds in non-surface active uncharged molecules. Cationic ester-based surfactants are hydrolyzed rapidly while anionic and also nonionic ester-containing surfactants are relatively resistant to hydrolysis.     

Sugar fatty acid ester surfactants: Structure and ultimate aerobic biodegradability

Ultimate aerobic biodegradabilities of an array of sugar ester surfactants were determined by International Standards Organisation method 7827, “Water Quality—Evaluation in an Aqueous Medium of the Aerobic Biodegradability of Organic Compounds, Method by Dissolved Organic Carbon” (1984). The surfactants were nonionic sugar esters with different-sized sugar head groups (formed from glucose, sucrose, or raffinose) and different lengths and numbers of alkyl chains [formed from lauric (C₁₂) or palmitic (C₁₆) acid]. Analogous anionic sugar ester surfactants, formed by attaching an α-sulfonyl group adjacent to the ester bond, and sugar esters with α-alkyl substituents were also studied. It was found that variations in sugar head group size or in alkyl chain length and number do not significantly affect biodegradability. In contrast, the biodegradation rate of sugar esters with α-sulfonyl or α-alkyl groups, although sufficient for them to be classified as readily biodegradable, was dramatically reduced compared to that of the unsubstituted sugar esters. An understanding of the relationship between structure and biodegradability provided by the results of this study will aid the targeted design of readily biodegradable sugar ester surfactants for use in consumer products.     

Cleavable Surfactants: A Comparison between Ester,Amide, and Carbonate as the Weak Bond

Cleavable surfactants, i.e., surfactants in which a weak bond has deliberately been inserted into the molecule, are of interest when remaining surface-active material at a surface can cause problems. Ester and amide bonds are established as week linkages in surfactants but these generate an acid when they hydrolyze. For some applications, acidic degradation products are unwanted. Surfactants with a carbonate bond between the polar headgroup and the hydrophobic tail are of interest for such purposes. In this article, we compare the physical–chemical properties of nonionic carbonate surfactants with those of the corresponding ester and amide surfactants. The half-lives of the different cleavable surfactants are also compared and it was found that a carbonate bond is slightly more stable to alkaline hydrolysis than an ester bond when present in otherwise identical structures. A nonionic Gemini surfactant with a carbonate bond in the spacer, which on hydrolysis decomposes into two identical single-tailed nonionic amphiphiles, is also presented. The hydrolysis kinetics for this surfactant was studied in some detail and it was found that it degrades much faster at low temperature than at higher temperature. This anti-Arrhenius type of hydrolysis kinetics is proposed to be due to the reverse solubility versus temperature behavior of ethoxylated surfactants.     

Synthesis and chemical hydrolysis of surface-active esters

A series of four homologous pure nonionic surfactants, all monoesters of tetra(ethylene glycol), were synthesized. The ester surfactants varied in the degree of substitution on the α-carbon of the acyl chain, from no substitution to 2-methyl, to 2-ethyl, and on to 2,2-dimethyl. All surfactants were based on C₈-acids except the 2-methyl-substituted, which was based on a C₇-acid. The ester surfactants were characterized by critical micelle concentration (CMC) and cloud point. Base-catalyzed hydrolysis was investigated by using ¹H NMR and tensiometry. The surfactants showed a pronounced difference in hydrolytic reactivity; the nonsubstituted surfactant was 90 times more reactive than the disubstituted, and the reactivity of the methyl-substituted surfactant was 14 times more reactive than the ethyl-substituted. Hydrolysis studies above the CMC revealed that the ester bond of the aggregated surfactant is protected from attack by hydroxide ions; thus, only surfactants in monomeric form are being cleaved.     

Sugar fatty acid ester surfactants: Biodegradation pathways

In previous work, we found that the presence of a sulfonyl or alkyl group adjacent to the ester bond of sugar ester surfactants is associated with a dramatic reduction in the rate of biodegradation relative to that of unsubstituted esters. In this study, we investigated the pathways followed during the biodegradation of sucrose laurate, sucrose α-sulfonyl laurate, and sucrose α-ethyl laurate to determine the reasons for their different biodegradation rates. Through the use of high-performance liquid chromatography and proton nuclear magnetic resonance spectroscopy, the nature of the intermediates formed during the biodegradation of these three key sugar esters was determined. It was found that sucrose laurate biodegradation occurs via initial ester hydrolysis. In contrast, sucrose α-sulfonyl laurate degrades by initial alkyl chain oxidation. This indicates that the ester hydrolysis pathway is blocked by the sulfonyl group adjacent to the ester bond so that biodegradation is forced to proceed via the slower alkyl chain oxidation pathway. Sucrose α-ethyl laurate was degraded at least in part by alkyl chain oxidation, indicating that ester hydrolysis was also inhibited by the presence of an ethyl group. It is therefore concluded that previously observed relationships between structure and biodegradability arise because of the influence that different structural elements have on the pathways followed during biodegradation.     

蔗糖酯表面活性剂化学合成工艺研究进展

蔗糖酯表面活性剂作为一种广受关注的生物基表面活性剂,大量应用于食品、医药和化妆品等领域。当前,蔗糖酯的合成主要采用直接酯化、酰氯酯化和酯交换法进行,其中酯交换法是最常用的方法,然而蔗糖与甲酯相容性差导致其存在蔗糖焦化结块、甲酯水解和皂化等副反应,严重影响反应效率和产品性能。基于此,该文对溶剂法、微乳化法和无溶剂法等蔗糖酯合成工艺进行了介绍,随后,着重介绍了相转移催化剂、固体碱催化剂、离子液体等新型催化技术和物理界面强化技术在蔗糖酯合成中的应用。同时,对高效固体碱催化剂设计和多过程耦合强化技术在蔗糖酯合成中的应用及其反应机制的研究进行了展望,以期为蔗糖酯的合成技术的发展提供技术指导。     

Nonionic cleavable ortho ester surfactants

A new class of cleavable surfactants based on the ortho ester link is described. Ortho ester surfactants were synthesized from a short-chain ortho ester, a fatty alcohol, and a poly(ethylene glycol) monomethyl ether. The triple functionality of the ortho ester link results in a mixture of surface-active and nonsurface-active species. Structures were confirmed by ¹H and ¹³C nuclear magnetic resonance. Hydrolysis characteristics at pH values ranging from 2 to 8 were determined. It was shown that, after a steep rise, hydrolysis curves flattened out before complete hydrolysis was reached. Ortho ester surfactants hydrolyze more rapidly than corresponding acetal surfactants. Hydrolysis rates are higher for purified samples and at higher temeprature, while plateau levels are higher for the purified surfactant mixtures and at lower pH. The origin of these results is discussed. Data also indicate that the hydrolysis mechanism changes with pH. A test of the loss of emulsification capacity for an ortho ester surfactant with time at pH values from 2 to 11.5 and at 22 or 50°C was carried out, showing rapid breaking of the emulsion at mild acid conditions and a requirement of pH≥10 for long-term stability. Surface tension and critical micelle concentration were determined for some of the surfactant mixtures. It was demonstrated that ortho ester surfactants possess excellent biodegradation properties. The new surfactants are promising candidates for use in industrial processes where temporary surfactant action is required.     

脂肪酸甲酯制备表面活性剂的研究与生产现状

生物柴油的迅猛发展使得脂肪酸甲酯作为重要化工原材料引起了广泛关注,并为其进一步开发应用提供了良好的机会和广阔的发展空间。本文论述了以脂肪酸甲酯为原料生产的各类可生物降解的表面活性剂,并对环氧乙烷加成物、脂肪酸甲酯α-磺酸钠、脂肪酸蔗糖酯等产品的性能、研究现状及目前企业生产概况等进行了重点介绍。     

表面活性剂在家用洗涤剂中的应用进展

论述了表面活性剂在家用洗涤剂中的应用现状和发展趋势,分析了直链烷基苯磺酸钠、α-烯基磺酸钠、脂肪醇聚氧乙烯醚硫酸钠、脂肪酸甲酯磺酸钠、脂肪醇聚氧乙烯醚、脂肪酸甲酯乙氧基化物、烷基糖苷等几种重要的表面活性剂的应用和市场情况,阐明了脂肪酸甲酯磺酸钠有望成为新一代有影响力的阴离子表面活性剂。指出家用洗涤剂的发展趋势将是功能化、浓缩化和液体化,表面活性剂将向油脂基和特种表面活性剂发展,其安全性也将倍受关注。建议加强油脂化学工业建设,为油脂基表面活性剂的发展打下坚实基础。     

阳离子及脂肪胺类表面活性剂的展望(英文)

过去的几年间 ,减产、兼并及重组在表面活性剂行业屡见不鲜 ,但其中也不乏增长机会。目前市场上阳离子型表面活性剂的产量近 80 0 0 0 0t。近几年 ,以北美及欧洲地区的市场用量最大且较为活跃。尽管总体增长趋缓 ,产品间的微调却始终未断。而产品的新旧转换又进一步推进了市场的前进。随着东南亚经济的复苏 ,南美及亚洲市场呈现增长势头 ,预计全球的增长将主要来自亚洲。介绍了阳离子表面活性剂的技术及其主要应用范围与市场情况。此项技术还在继续发展中 ,比如一些市场已从烷基胺 (四基胺 )转变为酯类四基胺 ,亦描述了几个大市场的情况及潜在增长的可能性     

羊毛脂琥珀酸酯磺酸盐加脂剂的制备及性能

将等物质的量的羊毛脂和马来酸酐在 6 0℃加热 2 0min ,加入催化剂对甲苯磺酸 ,在 10 0℃反应 3h ,可得到羊毛脂琥珀酸酯。调节pH值至 6～ 7,加入NaHSO3 饱和水溶液 ,反应 1h ,85℃时反应 2h ,最后升温并在减压下除去水分。向产物中加适量的过氧化氢 ,将未反应的亚硫酸氢钠氧化成硫酸钠 ,得羊毛脂琥珀酸酯磺酸盐。将其与氯化石蜡、硬脂酸聚氧乙烯酯及非离子表面活性剂复配 ,制得AS结合型加脂剂。透射电镜照片显示加脂剂乳液粒子尺寸为 0 5 μm以下 ,且分布均匀 ,产品具有良好的水分散性、耐酸性、耐盐性及良好的加脂性能     

Oxidized rapeseed oil methyl ester as a bitumen flux: Structural changes in the ester during catalytic oxidation

Structural changes occurring in the rapeseed oil methyl ester upon catalytic oxidation at 200 °C were examined. Oxidative decomposition of fatty acid chains to lower molecular weight compounds and the formation of oligomers were the major oxidation pathways at 200 °C. FT-IR and ¹H NMR examinations, as well as the fall in iodine number, revealed the disappearance of double bonds. Quantitative analysis of the rapeseed oil methyl ester and the liquid products of its oxidation showed that oxidation of fatty acid methyl esters possessing three and two double bonds was practically complete whereas for structures possessing one double bond the loss of unsaturation amounted to 25% only. The decrease in iodine number from about 110 to about 65 and the 1.5-fold increase in molecular weight of the liquid products in the course of 25-h oxidation suggest that only a part of the unsaturated bonds in the fatty acid methyl ester was engaged in the formation of liquid oligomers and volatile oxidation products. The addition of dicumyl peroxide promoted the formation of organic peroxides during the initial stage of oxidation, which resulted in a higher molecular weight of the liquid products. The volatile oxidation products were found to contain lower molecular weight aldehydes, ketones, free fatty acids and their methyl esters, alkylfurans, lactones, n- and isoalkanes. The reaction schemes for their formation were presented. The results of the study are of importance to the optimization of the conditions for oxidation of the ester in order to obtain a quality ecological bitumen flux.     

Microwave-Assisted Synthesis and Characterization of Stearic Acid Sucrose Ester: A Bio-Based Surfactant

Sugar esters of fatty acids are bio-based surfactants that were synthesized by transesterification of table sugar (sucrose) with stearic acid methyl ester (SAME) in high yield and purity using an optimized microwave-assisted method. The maximum surfactant product yield of 88.2% was obtained by combining reactants with potassium methoxide and irradiating the mixture with microwaves to achieve an ideal reaction temperature of 132 °C over 21 min. The synthetic procedure described herein minimized undesirable sugar pyrolysis as evidenced by retention of white color characteristic of a pure bio-based surfactant product. The experiment implemented Box–Behnken design for response surface methodology to refine reaction parameters for optimal product yield. The following parameters were augmented: the irradiation time, the mole ratio of catalyst to sucrose, and temperature.     

α-Sulfo Fatty Methyl Ester Sulfonate: A Review on Chemistry,Processing Technologies,Performance, and Applications in Laundry Detergents

α-Sulfo fatty methyl ester sulfonate (α-MES) is one of the anionic surfactants that is currently used commercially in the cleaning industry. Although the fundamental studies on α-MES were initiated as far back as the 1950s, it was only recognized as a class of surfactant in the 1980s. In the initial stage of development, α-MES has been associated with many technical impediments, which created a fear factor for the detergent industry to consider this oleo-based anionic surfactant for commercial production. However, all the technical adversities have been resolved after five decades of continuous active research and development activities. This paper will review the history, chemistry, process development, processing technologies, performance, commercial production, and applications of oleo-based based α-MES with special emphasis on palm oil-based α-MES. The paper also will highlight the challenges and adversities faced by the technology developers and product formulators toward the commercialization of α-MES as an active ingredient in the production of powder and liquid laundry detergents.     

Chemical reactions of fatty acids with special reference to the carboxyl group

Unsaturated fatty acids contain unsaturated centres and the carboxyl group both of which can be modified to give a range of interesting and useful compounds. The former have been discussed in detail in two recent references [8, 9] and therefore this paper will be concerned with the reactions of the carboxyl group and its derivatives. Attention is directed to the lactones, alcohols and their ethoxylates and sulfates, to the preparation of cleavable surfactants (acetals, ketals, ortho esters and ester quats), Guerbet alcohols and acids, alkyl polyglycosides and to amines and other nitrogencontaining compounds.     

Preparation and Characterization of C10–C14 Alkyl Cellulose Ester Sulfate Surfactant

The aim of this work is to synthesize surfactants based on cellulose with different molecular weights. Raw cotton cellulose was tailored into cellulose segments with different molecular weights by a hydrothermal process, then the average degree of polymerization (DP) was determined by viscosimetry and the molecular weight distribution was estimated by gel permeation chromatography. The C₁₀–C₁₄ alkyl cellulose ester sulfate surfactants were prepared by hydrophilic sulfonation and hydrophobic esterification. The surface tension of the surfactants solution was obtained by the Wilhelmy plate method. Results showed that the cellulose segments presented a broader distribution compared with the raw material. The critical micelle concentration (CMC) value decreased from 1.08 to 0.86 wt% as the hydrophobic chain length was increased from 10 to 14. The CMC values of cellulose surfactants with C₁₄-acyl chloride hydrophobization decreased from 1.32 to 0.86 wt% as the DP was decreased from 2,700 to 296.     

不同链长可聚合硼酸酯表面活性剂的合成及性能

以硼酸、N-羟甲基丙烯酰胺、烷基二乙醇胺等为主要原料,合成了链长为八烷基(octyl borate ester,简称为OBE)、十二烷基(lauryl borate ester,简称为LBE)和十六烷基(hexadecyl borate ester,简称为HBE)的可聚合硼酸酯表面活性剂,研究了反应溶剂、阻聚剂、反应温度等因素对收率的影响,由IR和1HNMR对产物进行了结构表征。得到的优选条件为溶剂苯50 mL、阻聚剂吩噻嗪质量分数0.8%、反应温度60℃,LBE收率可达93.3%,OBE和HBE收率分别可达95.7%和89.6%;并考察了3种硼酸酯的表面张力和乳化性能,25℃时,OBE的CMC为5.2 mmol/L,γCMC为31.8 mN/m;LBE的CMC为0.069 mmol/L,γCMC为29.5 mN/m;HBE的CMC为0.087mmol/L,γCMC为28.6 mN/m。     

高压下CO2在几种物理吸收剂中的溶解度测定

为开发新型高效物理吸收溶剂,采用恒定溶剂法,测定了不同温度、压力条件下,CO2气体在酮、碳酸酯、乙酸酯、二酸酯、醚及醚酯化合物等不同纯溶剂中的溶解度,温度变化282.76-302.81 K,压力最高可达4 MPa.结果表明:在此测定条件下,CO2在物理溶剂中的溶解度符合亨利定律,溶解度随压力升高而增大,随温度升高而减小...     

酯基Gemini季铵盐阳离子表面活性剂的研究进展

含酯基季铵盐表面活性剂具有良好的表面活性及生物降解性能而广受国内外学者关注。本文回顾了近几年来国内外对可降解的含酯基双子季铵盐（对称型、非对称型及含杂环型）的研究概况,并简要介绍产物作为消毒杀菌剂、金属腐蚀抑制剂、乳化剂、泡沫剂、基因载体等在工业上的应用。最后,指出通过分子设计开发性价比优异的新型表面活性剂、优化合成工艺、提高与传统表面活性剂的配伍性能等是当前的研究热点。