Effect of alkyl carbon chain length and ethylene oxide content on the performance of linear alcohol ether sulfates

A series of linear alcohol ether sulfates varying in alkyl carbon chain length and ethylene oxide content was evaluated with respect to surface activity, viscosity, foaming, and detergency. Performance data agree well with surface property data. A low level of EO is best in terms of effectiveness and efficiency in lowering surface tension, which is why a low-mole ether sulfate salt-thickens better, produces foam which is more tolerant of soil, and gives good detergency performance. A lauryl-range alkyl carbon chain length is best for foaming and salt-thickening, but a higher carbon chain length appears to be better for detergency performance.     

Phase behavior and detergency study of lauryl alcohol ethoxylates with high ethylene oxide content

Nonionic surfactants such as fatty alcohol ethoxylates have been extensively used in many detergent applications, because of their high calcium ion tolerance, low critical micelle concentrations, and mildness. Although ethoxylates containing high ethylene oxide (EO) content (EO>10 moles) score higher than their low-FO counterparts on many of these desired properties, they have not been studied adequately in the context of detergency, primarily because their cloud points (CP) are higher than normal wash temperatures, typically >100°C, and thus cannot be measured. However, once the CP are manipulated appropriately using salting-out electrolytes, these surfactants can offer certain distinct advantages in terms of their molecular and phase structure. We have studied the phase structure and clouding behavior of tetradecyl ethylene-oxide mono dodecyl alcohol (C₁₂EO₁₄), a broad-range ethoxylate, as a function of the concentrations of various electrolytes. We found that, beyond a certain critical concentration, the CP decreases monotonically with increasing salt concentration. For sodium salts of various anions, the CP depression is inversely proportional to the lyotropic number of the anion. Similarly, for chloride salts of various cations, CP depression is inversely proporitional to the lyotropic number of the cation However, the effect of changing anion is stronger than that of changing cation. A micrograph of a water penetration scan at room temperature indicates the presence of isotropic L₁; hexagonal, isotropic L₂; and solid phases with increasing surfactant concentration. As is the case with low-FO nonionics, a maximum in detergency of model oily soils was found to correlate well with the minimum in oil/water interfacial tension when plotted vs. temperature. Ross Miles foam height increases with increasing concentration of salt.     

The prediction of ethylene oxide distributions in mixed alcohol ethoxylates

Supercritical fluid Chromatographic analyses of ethoxylates of 2- ethylhexanol in the pure state and in mixtures were used to determine relative propagation- to- initiation ethoxylation rate constants. Earlier work with normal octanol was verified in that ethylene oxide distributions were found to be unaffected by the presence of other alcohols in the ethoxylation of mixed alcohols. An apparent decrease in the relative ethoxylation rates with increasing number of ethylene oxide monomers in ethoxylates is attributed to truncation of the measured distributions and is eliminated by adding small amounts of higher ethoxylates to the distribution. The Weibull- Tornquist effect of decreasing relative rate constants as the overall average ethylene oxide- to- alcohol ratio increases was again observed. Rate constants of the ethoxylation of 2- ethylhexanol and its ethylene oxide adducts relative to the ethoxylation of normal octanol were determined from the analysis of ethoxylates of their mixtures. A computer model using averaged relative rate constants was developed that effectively predicts the ethylene oxide distributions in ethoxylates of alcohol mixtures. To whom correspondence should be addressed at Exxon Chemical Company, Intermediates Technology Division, P.O. Box 241, Baton Rouge, LA 70821     

The effect of “peaking” the ethylene oxide distribution on the performance of alcohol ethoxylates and ether sulfates

In comparison to conventional ethoxylates, a “peaked” ethoxylate has less unethoxylated alcohol, is more soluble, and has a higher concentration of the more desired homologs. A “peaked” ethoxylate therefore has a lower odor, is easier to formulate into liquids, and can perform better in terms of detergency and wetting performance. Since “peaked” ethoxylates have less unethoxylated alcohol, less alcohol sulfate is formed during sulfation. Decreasing the content of alcohol sulfate increases the capacity to salt-thicken and can potentially improve skin mildness.     

Viscosity,pour point,and chain length relations for the alcohol ethoxylates

Because pour points of surfactant alcohol ethoxylates are important and tedious to determine experimentally, it is desirable to have methods for calculating pour points from other properties, e.g., viscosities (1). To facilitate calculating pour points, several types of equation were developed that relate (a) chain lengths of the alcohol ethoxylates to pour points, (b) chain lengths to viscosities, and (c) viscosities to pour points.     

Effect of hydrophobe structure on performance of alcohol ethoxylates

Alcohol ethoxylates are versatile surfactants because both the hydrophobic and the hydrophilic moieties can be varied readily to change performance. Many studies have focused on the effect of changes in the average length of the hydrophobe and the nature of the hydrophile. Less frequently studied, however, has been the effect on performance of hydrophobe structure, yet this can be varied easily by changing the alcohol feedstock used to make the alcohol ethoxylate. This study compares the performance of alcohol ethoxylates derived from oleochemical alcohol and oxo-alcohols derived from kerosene, butylene, or coal by the Fischer-Tropsch process. Two aspects of hydrophobe structure were found to be important for performance of alcohol ethoxylates: the overall linearity of the parent alcohol and the degree of substitution at the C2 carbon. As the linearity of the parent alcohol increases, the critical micelle concentration (CMC) decreases and the surface tension at the CMC increases. Increasing substitution at the C2 carbon increases the amount of unethoxylated alcohol in the ethoxylate but decreases the inverse cloud point temperature, wetting time, and foam stability in the absence of soil.     

碳链对脂肪醇硫酸钠性能影响的研究

测定不同碳链脂肪醇硫酸钠的物化性能,如表面张力、cmc值、乳化、接触角、耐硬水性和泡沫等。结果表明,C12～14醇硫酸钠降低表面张力的效果最佳。随着烷基碳链变长,脂肪醇硫酸钠的接触角变大且耐硬水性能也变差。C8～10醇硫酸钠的发泡力最差,且C16～18醇硫酸钠因其耐硬水性能差,其发泡力随着水硬度的增加而下降。以C16～18醇硫酸钠的乳化性能最好。     

Determination of ethylene oxide content inn-Alcohol ethoxylates by proton nuclear magnetic resonance spectroscopy

Proton Fourier transform nuclear magnetic resonance spectral data were collected onn-alcohol ethoxylates and used to calculate the percent ethylene oxide (EO) content of then-alcohol ethoxylate without an internal or external standard. The accuracy and precision of the method were determined from ten repetitive analyses of hexaethylene glycol monon-dodecyl ether. The standard deviation was 0.23 wt% EO with a relative standard deviation of 0.40%. The method had a relative error of +0.55% and an absolute error of +0.32% EO. This paper was presented at the 20th ISF World Congress/83rd AOCS Annual Meeting and Exposition in Toronto, Canada, May 10–14, 1992.     

Effect of chain length on the rate of quaternization of alkyl amines

Trialkyl amines from triethyl to tristearylamine were quaternized with benzyl chloride and compared for the effect of chain length on the rate of quaternization. Triethylamine reacted about twice as fast as tripropylamine with virtually no chain-length effect from propyl to stearyl. Results are compared to previous rate studies on steric hindrance and chain-length dependence.     

Effect of alkyl chain length on the thermophysical properties of pyridinium carboxylates

In the present study,new series of pyridinium carboxylate protic ionic liquids (PILs) were synthesized by pairing pyridinium cation with carboxylate anion from C1-C3 forming pyridinium formate ([CsH6N+][HCOO-]),pyridinium acetate ([CsH6N+][CH3COO-]) and pyridinium propionate ([C5H6N+][CH3CH2COO-]) respectively.The physical properties namely,density,viscosity,surface tension (298.15-343.15) K,and refractive index (293.15-323.15) K were measured.Thermal properties namely,glass transition temperature,molar heat capacity,and thermal decomposition temperatures were also determined.The thermal expansivity was calculated using the experimental density data.The effect of increasing the alkyl chain length on the thermophysical properties of the pyridinium carboxylate PILs has been evaluated.As expected the physical properties i.e.density,viscosity,surface tension and refractive index of the investigated pyridinium carboxylates decreased with increasing temperature.In general pyridinium carboxylate PILs possessed low viscosity,high thermal stability and excellent hydrogen bonding capability,and these properties lead them to outperform conventional solvents employed for lignin dissolution.     

The use of aliphatic alcohol chain length to control the nitrogen type and content in nitrogen doped carbon nanotubes

Nitrogen doped carbon nanotubes (N-CNTs) were synthesized using acetonitrile/alcohol mixtures as the nitrogen, carbon and oxygen sources using the chemical vapor deposition (CVD) method. XPS analysis of the CNTs produced from an acetonitrile/ethanol mixture using different CVD temperatures (700–1000 °C), revealed that nitrogen incorporation in N-CNTs decreased with an increase in CVD temperature and that the type of nitrogen species incorporated also varied. Molecular nitrogen and a low content of pyridinic nitrogen was obtained in N-CNTs grown at 700 and 800 °C, while quaternary nitrogen was noted in all N-CNTs grown. Use of 20% acetonitrile/ROH (R = CH₃, C₂H₅, C₄H₉, C₅H₁₁, C₇H₁₅ and C₈H₁₇) mixtures allowed the C/O ratio to be changed whilst the N content in the precursor mixture was kept constant. The N content in the N-CNTs grown at 850 °C increased with the alcohol chain length and also controlled the nitrogen species incorporated, an effect related to the oxygen content of the reactant mixtures.     

Determination of ethylene oxide oligomer distributions in alcohol ethoxylates by HPLC using a rotating disc-flame ionization detector

A high performance liquid chromatographic (HPLC) method has been developed for the quantitative determination of ethylene oxide (EO) oligomer distributions (% wt) in acetylated alcohol ethoxylates, R(OCH₂CH₂)_nOH, from n=0, 1 to n=30 using a rotating disc-flame ionization detector. Both single carbon number and mixed carbon number alcohol-based (NEODOL® ethoxylates) samples have been analyzed by gradient elution with 2 different solvent systems on a Waters μ-Porasil column. With both solvent systems, 95% hexane is the initial solvent but with one system, 100% acetone is the final solvent and with the other, 10% methanol/90% acetone is used. The latter solvent elutes the higher ethoxylates from n=21 to n=30 quantitatively from the μ-Porasil column which the 100% acetone solvent fails to do. The 100% acetone solvent separates n=2 and n=3 from n=0,1 which the methanol-containing solvent does not do. Response factors for n=3 and n=8 have been experimentally determined and the response factors for the other EO units have been calculated from these 2 results. The corrected EO oligomer distributions for both NEODOL® 25-9 and NEODOL® 23-6.5 determined by HPLC are in good agreement with those determined earlier by circular thin layer chromatography (up to n=16 can be determined by this method). The average EO numbers determined by the HPLC method and by a wet chemical (phthalic anhydride) method are in excellent agreement for the above 2 samples and a sample of NEODOL® 23-7.5. The results are discussed in terms of Snyder’s theory for gradient elution in HPLC using the gradient steepness parameter.     

Effect of homolog distribution on the toxicity of alcohol ethoxylates

Previous work established a high correlation between the potential environmental toxicity of oxyethylenated nonionic surfactants and the average degree of ethoxylation. For this reason, it was considered of interest to determine whether a narrow- or broad-range homolog distribution of polydisperse commercial alcohol ethoxylates would influence toxicity. Ethoxylated fatty alcohols, both linear and branched, were synthesized with sodium hydroxide or an unconventional calcium-based catalyst. Toxicity tests were run onDaphnia magna and luminescent marine bacteria. Toxicity of ethoxylated alcohols as a function of type of ethoxylate homolog distribution (narrow or broad) and average degree of polyaddition is analogous for both test species. However, narrow-range ethoxylates show lower toxicity values than conventional ethoxylates. Differences in toxicity values between broad- and narrow-range ethoxylates depend on the degree of ethoxylation.     

Mechanical reinforcement of polyethylene using n‐alkyl group‐functionalized multiwalled carbon nanotubes: Effect of alkyl group carbon chain length and density

Polyethylene (PE) is one of the most produced synthetic resins in the world. Functionalized multiwalled carbon nanotube (MWCNT) is a potential nanoscale filler to realize the next generation strong and multifunctional PE composites. We demonstrate that MWCNTs grafted with short n‐alkyl groups are effective nanofillers for mechanical reinforcement of PE composites. At 1 wt% filler loading, the yield stress and Young's modulus improve significantly up to 54 and 63% compared with neat PE, respectively. Among ductile properties, tensile strength increases up to 30%; ultimate strain is preserved; and toughness increases up to 33%. More important, we show that short n‐alkyl groups can be grafted on MWCNTs much easier than long chain polymers. Further, we find that alkyl groups of C14–C18 chains have the optimum length for reinforcement. The optimum density of grafted alkyl groups is around 0.390–0.423 μmol/mg when the C14 alkyl groups are used. Overall, the results manifest that MWCNTs grafted with n‐alkyl groups with suitable length and density are efficient nanoscale fillers for high‐performance PE composites. POLYM. ENG. SCI., 54:336–344, 2014. © 2013 Society of Plastics Engineers     

Effect of alkyl chain length grafted to graphene nanoplatelets on the characteristics of polypropylene nanocomposites

To improve the compatibility of graphene nanoplatelets (GNPs) to polypropylene (PP), alkyl chains were grafted to the GNPs’ surfaces by chemical reactions between alkyl amines and the corresponding functional groups of the GNPs. Hexylamine, dodecylamine, and octadecylamine were used respectively to prepare three different alkyl‐grafted GNPs (alkyl‐GNPs) with different alkyl chain lengths. Functional group analysis of the alkyl‐GNPs by Fourier transform infrared confirmed the alkyl‐grafting reaction. PP/alkyl‐GNP nanocomposites with 0.5 phr of hexyl‐, dodecyl‐, or octadecyl‐GNPs were prepared respectively by melt‐blending and compression molding and their mechanical and thermal properties and fracture surfaces morphology were investigated. With increasing alkyl chain length the flexural strength and melting temperature increased marginally but the flexural modulus, impact strength and storage modulus of the nanocomposites increased to a large extent. POLYM. ENG. SCI., 59:752–756, 2019. © 2018 Society of Plastics Engineers     

芳基烷基磺酸盐链长对烷烃的油-水动态界面张力的影响

采用旋转滴法测定系列自制芳基烷基磺酸盐（C_nNPAS, n=8,10,12,14,16）水溶液对烷烃的油-水动态界面张力,考察了表面活性剂烷基链长、表面活性剂浓度、弱碱浓度、烷烃碳数等因素对油-水动态界面张力的影响。结果表明,增大C_nNPAS的烷基链长和碱含量均会使界面张力达到稳定值的时间增长;增加C_nNPAS浓度和烷烃碳数均会使界面张力动态变化加快,达到平衡所需时间减少。C_nNPAS表面活性剂可在低浓度范围较明显地降低界面张力,而随着浓度的增加界面张力回升明显。     

载体助剂对环氧乙烷银催化剂性能的影响

采用Zr和Cr助剂改性银催化剂载体氧化铝,探索影响环氧乙烷合成银催化剂初期选择性的关键因素。结果表明,载体中添加的Zr和Cr助剂,负载的银粒子及协同助剂均未在氧化铝表面形成较强的酸性中心,Zr和Cr组分间存在协同效应,促进高价态的Re元素的形成,Zr组分能激发出特征峰信号更强的Cr 2p峰。添加Zr助剂的载体与不加Zr的载体相比,在强化负荷条件下,制成的银催化剂初期选择性高出约2%,初期反应温度高出约6℃。     

Effect of secondary alcohol ethoxylates on behavior of triolein-water-surfactant systems

Study of the equilibrium phase behavior of systems containing water, triolein and secondary alcohol ethoxylates showed that a D or microemulsion phase, which solubilized significant amounts of triolein, formed at temperatures as low as 25°C when the surfactant was a suitable mixture of TERGITOL 15-S-3 and 15-S-5 (Union Carbide, Charleston, WV) with average ethylene oxide numbers of 3 and 5, respectively. In previous work with pure C₁₂ linear ethoxylates and triolein, the D phase had formed only at temperatures above about 55°C. Based on the earlier studies, formation of the D phase would be expected to improve soil removal from synthetic fabrics by a solubilization-emulsification mechanism. When sufficient oleyl alcohol was mixed with triolein, the D phase was observed at 25°C with Tergitol 15-S-5 alone. Observation of dynamic behavior in this system for triolein-oleyl alcohol drops injected into surfactant-water mixtures revealed that intermediate phases frequently formed near the drop surfaces and that considerable spontaneous emulsification of triolein occurred for appropriate drop compositions. Experiments with drops initially attached to individual polyester fibers confirmed that little oil remained on the fibers when emulsification was extensive. This mechanism involving spontaneous emulsification provides a means for soil removal different from that found previously in other systems, where the soil was solubilized into an intermediate phase, and this phase was emulsified by externally imposed agitation.     

模板剂碳链长度对MCM-41晶体结构的影响

The mesoporous molecular sieve （MCM）-41 using ionic liquid as template has been prepared. The typical template of ionic liquid was [C16mim]X. In this article, the use of 1-alkyl-3-methylimidazolium （[Cnmim]Br, where n= 12,14,16,18,20） salts as templates in the synthesis of MCM-41 is reported. The results showed that the synthesized MCM-41 had uniform pore diameter, high surface area and stable framework. The largest surface area of MCM-41 was the one prepared with [C14mim]Br as template. When using [C18min]Br as template, the narrowest pore distribution sample was obtained and the effect of surface tension of template solution to MCM-41 was first discussed.     

异构十醇聚氧乙烯醚与阴离子表面活性剂复配体系的性能研究

对异构十醇聚氧乙烯醚(IC_(10)EO_n)、十二烷基苯磺酸钠(LAS)和脂肪醇聚氧乙烯(2)醚硫酸钠(C_(12~14)E_2S)的水溶性进行分析,研究了LAS和C_(12~14)E_2S对异构十醇聚氧乙烯(8)醚(IC_(10)EO_8)浊点的影响,同时考察了IC_(10)EO_8与LAS和C_(12~14)E_2S复配体系的润湿力、泡沫性能、去污力等。结果表明,在25℃下,当IC_(10)EO_n的EO加合数为3,8和9时可与水以任意比例互溶,不会形成凝胶;在IC_(10)EO_8与LAS和C_(12~14)E_2S的复配体系中,当LAS和C_(12~14)E_2S的质量分数大于0.6%时,浊点迅速上升;IC_(10)EO_8与LAS和C_(12~14)E_2S的质量比在3∶1~1∶3范围内,复配体系的润湿性能优于单一表面活性剂,当IC_(10)EO_8与LAS和C_(12~14)E_2S的质量比为1∶1时,润湿性能最佳;IC_(10)EO_8的泡沫性能较差,随着阴离子表面活性剂的含量增加,复配体系起泡力逐渐增强,泡沫稳定性呈不规则变化;加入一定量的阴离子表面活性剂可提高IC_(10)EO_8的去污力。