Corrosion inhibition efficiency of some hydrophobically modified chitosan surfactants in relation to their surface active properties

This work deals with surface activity and corrosion inhibition efficiency of the natural polymer chitosan and its hydrophobically modified derivatives (eight polymeric compounds). Chitosan was found to be inactive at interfaces but the hydrophobic modification using different aliphatic and aromatic substituents renders the products surface active polymers. From the obtained data it was found that the surface active properties increased by increasing the hydrophobic character of these polymers.Chitosan and its based surfactants were investigated as corrosion inhibitors for carbon steel in 1 M HCl solution using the potentiodynamic polarization method. The resulted corrosion inhibition efficiency situated between 67.56% and 93.23% at 250 ppm and 25 °C. The inhibition efficiency was discussed on the light of surface active properties and the chemical structure of the used derivatives. The quantum chemical calculations were performed for some chitosan derivatives. The charge density distribution, highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), and dipole moment were considered.     

四聚磺酸盐表面活性剂的合成及其表面化学性能

以季戊四醇、环氧氯丙烷、十二醇、1,3丙烷磺内酯等为原料,经过醚化、开环、磺化反应,合成了四聚磺酸盐表面活性剂四[2-氧丙撑磺酸钠-3（十二烷氧基）丙烷氧基]新戊烷TTS（Ⅲ）。采用元素分析和红外光谱对产物结构进行了表征。通过表面张力的测定研究了其在不同温度下的表面化学性能。结果表明,产品具有较低的临界胶束浓度（Ccmc）和优良的表面活性。在40℃时,Ccmc和临界表面张力（γcmc）分别为6．85×10^-5mol／L和25．59mN／m。随着温度的升高,Гmax值下降,Amin升高,Cmcm／c20也随之升高。     

多元醇类表面活性物质的浊点行为在钻井液中的应用

介绍了近期多元醇类表面活性物质的基本物理化学性能研究,如临界胶束温度CMT、临界胶束浓度CMC、浊点行为及影响因素.对于多元醇型非离子表面活性物质,随浓度升高,临界胶束温度逐步降低;多元醇的临界胶束浓度随温度增加急剧下降;多元醇的浊点不仅取决于非离子表面活性剂的分子结构,而且受添加物(如无机电解质、极性有机物、表面活性剂、多元醇等)的影响很大,同时与非离子表面活性剂的浓度也有关系.研究了温度对多元醇钻井液体系润滑性能的影响,探讨了多元醇类表面活性物质作为钻井液润滑剂的作用机理.     

Formation of water-in-diesel oil nano-emulsions using high energy method and studying some of their surface active properties

In this work, formations of water-in-diesel oil nano-emulsions using water/mixed nonionic surfactant/diesel oil system have been studied. The high energy emulsification method was used to form three emulsions using different water contents: 5%, 10% and 14% (v/v) namely; E1, E2 and E3, respectively. These nano-emulsions were stabilized with emulsifiers having different Hydrophilic–Lipophilic Balance (HLB) namely; span 80 (HLB = 4.3), emarol 85 (HLB = 11) and their mixture (SE) with HLB = 10. The effect of water on the droplet size formation has been investigated. The interfacial tension and thermodynamic properties of the individual and emulsifiers blends have been studied. The interfacial tension (γ) measurements at 30 °C were used to determine the critical micelle concentration (CMC) and surface active properties of these emulsifiers. The water droplet sizes were measured by dynamic light scattering (DLS). From the obtained data, it was found that, mean sizes between 19.3 and 39 nm were obtained depending on the water content and concentration of blend emulsifiers (SE). Also, the results show that, the interfacial tension (γ) gives minimum value (10.85 mN/m) for SE comparing with individual emulsifier (17.13 and 12.77 mN/m) for span 80 and emarol 85, respectively. The visual inspection by TEM showed that the obtained results support the data obtained by dynamic light scattering.     

Synthesis of polymeric additives based on itaconic acid and their evaluation as pour point depressants for lube oil in relation to rheological flow properties

Modification of the wax crystal habit practical interest during transportation processing of lube oil at low temperature. Various pour point depressant (PPD) additives can facilitate this modification by different mechanisms. Comb shaped polymer additives are known to depress the pour point of lube oil by providing different nucleation sites for the precipitation of wax. This paper describes performance based design, synthesis, characterization and evaluation of comb shaped polymeric additives. Alkyl itaconates were prepared by the esterification of itaconic acid with different saturated alcohols C₁₆/C₁₈/NAFOL 20+A (C_av = 20)/NAFOL 1822 B (C_av = 22). The four synthesized monomers were characterized and copolymerized with styrene in different molar ratios. All the products were characterized by infra-red (FTIR), Nuclear Magnetic Resonance (NMR) Spectroscopy and Gel permeation chromatography (GPC). Rheological properties of lube oil (with and without additives) were studied by Brookfield viscometer. In this study the additives based on itaconic acid were evaluated as good PPD and rheology modifiers.     

原油组分对化学驱表面活性剂界面张力的影响

为提高化学驱油技术的使用效率,有效掌握表面活性剂的界面张力变化因素,开展了原油组分对表面活性剂界面张力的影响研究。应用原油分离提纯技术、GC-MS、红外光谱和核磁共振分析方法,从原油中分离出石油酸,分析其组分间的相互关系,总结界面张力变化规律。实验结果表明,原油组分中石油酸是影响界面张力的主要成分,其中异构脂肪酸是降低界面张力的重要贡献者。     

Effect of the chemical structure on the viscosity-temperature characteristics and thermo-oxidative properties of esters of cyclic polyols

The relationship between the chemical structure and the viscosity-temperature characteristics and thermo-oxidative properties of esters of cyclic neopolyols and bicyclic diols was studied. A number of features that allow experiments to be run in a targeted and selective manner were revealed.     

Synthesis of some novel non ionic surfactants based on tolyltriazole and evaluation their performance as corrosion inhibitors for carbon steel

Five new synthesized non ionic surfactants (I–V) were synthesized and characterized using FTIR and NMR spectroscopic methods. Performance of the synthesized compounds as corrosion inhibitors for X- 65 type carbon steel in oil wells formation water was investigated by various techniques such as weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). It was found that the percentage inhibition efficiency (η%) increases by increasing the inhibitor concentration until the critical micelle concentration (CMC) is reached. Also, the results showed enhancement in inhibition efficiencies with increasing both molecular size of the surfactant and the degree of ethoxylation. Potentiodynamic polarization curves indicated that the inhibitors under investigation act as mixed type. The data obtained from electrochemical impedance spectroscopy (EIS) were analyzed to model the corrosion inhibition process through equivalent circuit. Finally, the nature of the protective film formed on carbon steel surface was analyzed by SEM and EDX techniques.     

Effect of the chemical structure on the lubricity of hexenylsuccinic acid esters

The correlation between the chemical structure and the lubricity of various esters of hexenylsuccinic acid was revealed, which makes it possible to carry out experiments in a rational and selective manner.     

Effect of the structure of polyisobutenes on the reaction of their addition to maleic anhydride

It was shown that for the polyisobutenes used in production of succinimide additives, the conditions of conducting the reaction that ensure the maximum yield of the final product are not a function of the a-isomer content in them. Alkenyl succinic anhydride is basically formed as a result of maleic anhydride reacting with isomers with the structure RCH₃C=CH₂ and RCH₃C=CHCH₃. Due to the reversibility of alkenylation of maleic anhydride, it is impossible to completely utilize the potential of polyisobutenes. __________ Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 3, pp. 49–50, May–June, 2008.     

Effect of the chemical structure of hexenyl succinic acid esters – the foundation of synthetic oils – on their dynamic viscosity

The correlation between the dynamic viscosity and chemical structure of hexenyl succinic acid esters is investigated in a wide temperature range from −30 to +10 °C for different rotation frequencies.     

Effect of active species in crude oil on the interfacial tension behavior of alkali/synthetic surfactants/crude oil systems

The effect of active species present in crude oil on the interfacial tension （IFT） behavior of alkali/synthetic surfactants/crude oil systems was studied. The system consisted of heavy alkyl benzene sulfonate, sodium chloride, sodium hydrate and Daqing crude oil. Experimental results indicated that active species would diffuse from oil/aqueous interface to aqueous phase and finally an equilibrium could be reached in the system with increasing contact time. Moreover, the minimum IFT and equilibrium IFT values increased with increasing contact time and a linear relationship existed between dynamic IFT and f^-1/2 when IFT value approaching the minimum and after the minimum IFT was reached. This indicated that the dynamic IFT-time behavior was diffusion controlled. The oil and aqueous phases were analyzed by infrared （IR） spectroscopy. IR spectra of oil and aqueous phases illustrated that the content of active species in the oil phase decreased, but the content of active species in the aqueous phase increased after alkali reacted with crude oil. This indicated that the active species present in oil played an important role in reducing IFT.     

Effect of nonionogenic surfactants and a magnetic field on the rheological properties of highly viscous crude oils

The rheological properties of crudes from the Mordovo-Karmaly and Mortukovsk fields were investigated at 10–70°C in the presence of surfactants (SF) and in a magnetic field. The maximum decrease in the characteristics was attained in UHF treatment for the Mortukovsk crude and on addition of IPG-12 activating additive for the Mordovo-Karmaly crude. __________ Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 3, pp. 31–33, May–June, 2008.