Effect of oilfield chemicals on the cloud point of nonionic surfactants

Alghamdi, Abdullah; Nasr‐El‐Din, Hisham A.

doi:10.1016/s0927-7757(96)03860-5

Cited by 62 publications

(26 citation statements)

References 35 publications

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“…It can be seen that addition of NaCl to the AMT solution increases the CP, whereas addition of dextrose, sucrose, and urea decreases the CP. Al-Ghamdi and Nasr-El-Din (1997) observed in their experiments that addition of NaCl to the Triton-X nonionic surfactant solutions reduces the CP, while addition of urea increases the CP. In this case, Cl À ions are water structure makers and decrease solute solubility, lowering the CP of nonionic surfactants due to the salting-out effect.…”

Section: Resultsmentioning

confidence: 99%

“…The cloud point (CP) phenomenon has been generally observed in nonionic surfactant micellar solutions at elevated temperatures (Schott, 1984;Xie et al, 1989;Gu and Galera-G o omez, 1995;Al-Ghamdi and Nasr-El-Din, 1997). The increase in turbidity of the surfactant solution at the CP is generally considered to be due to the formation of large aggregates (Paradies, 1980;Glatter et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

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Cloud Point and Dye Solubilization Studies of Amphiphilic Drug Solutions: The Effect of Electrolytes and Nonelectrolytes

Kim

Yoo

et al. 2006

Chemical Engineering Communications

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The effect of electrolytes and nonelectrolytes on the micellar behavior of amitriptyline (AMT), an amphiphilic drug, has been investigated using cloud point (CP) and dye solubilization techniques. The critical micelle concentration (cmc) of AMT determined by the Wilhelmy plate method was about 40 mM in the presence of 10 mM sodium phosphate, and it reduced to about 20 mM in the presence of 500 mM sodium phosphate. Interestingly, the CP phenomenon was observed even below the cmc in cationic AMT solutions. Increasing AMT concentration reduced the CP below the cmc, while it had the opposite effect above the cmc. An increase in the pH of the AMT solutions from 6.2 to 6.8 at a given AMT concentration decreased the CP and increased the AMT micellar size. Addition of an electrolyte such as sodium chloride to 100 mM AMT in water increased both the CP and the AMT micellar size. On the other hand, added nonelectrolytes such as dextrose, sucrose, and urea decreased both the CP and the micellar size. Experimental results have been interpreted in terms of electrostatic effect and interactions between additives and AMT head groups.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cloud Point and Dye Solubilization Studies of Amphiphilic Drug Solutions: The Effect of Electrolytes and Nonelectrolytes

Kim

Yoo

et al. 2006

Chemical Engineering Communications

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“…1 The cloud point (CP) phenomenon is generally observed in nonionic surfactant micellar solutions when the temperature of the surfactant solution is raised to a certain value. [5][6][7][8][9] The increase in turbidity at the CP is generally considered to be due to formation of large aggregates. 10 There is some debate on the relative importance of micellar interaction and micellar growth to the CP.…”

Section: Introductionmentioning

confidence: 99%

A Cloud Point Study on the Micellar Growth of an Amphiphilic Drug in the Presence of Alcohol and Ionic Surfactant

Kim

Shah

2003

J. Phys. Chem. B

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Cloud point (CP) measurements have been performed to investigate the influence of alcohols (C 2 -C 10 OH) on the micellar growth of amphiphilic drug amitriptyline (AMT) in the presence of salt and surfactant. In the case of shorter-chain alcohols (C 4 OH or C 5 OH), the CP increased with increasing alcohol concentration in the presence of a small amount of sodium phosphate because they partition very little in AMT micelles. On the other hand, it steeply decreased with increasing alcohol concentration in the case of longer-chain alcohols (C 8 OH or C 10 OH) due to their considerable partitioning in AMT micelles. The effect of hindering the micellar aggregation was enhanced as the alcohol chain length increased in the case of shorter-chain alcohols. The CP became less sensitive to addition of C 6 OH at higher sodium phosphate concentrations, resulting from incorporation of more C 6 OH molecules into the enlarged micelles. Addition of cationic surfactant cetylpyridinium chloride to the AMT micellar solutions increased the CP because cetylpyridinium cations affect electrostatic interactions with the cationic AMT headgroup, while addition of anionic surfactant, sodium dodecyl sulfate, decreased the CP because of penetration of dodecyl chains into the micelles, resulting in a micellar growth.

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“…Diamond is surfactant concentration assayed after phase separation; Triangle is surfactant concentration calculated by conservation of mass after phase separation; Circle is determined from cloud point method and fork is CMC, which indicates that the nonionic surfactant concentration in the dilute phase of the cloud point system is higher than the CMC phenomenon and a below room temperature is taken as the cloud point of Triton X-45 [23]. There is a same phenomenon for nonionic surfactant Brij 30 and Span 20 etc [23,32] in spite of the fact that a phase separation into two clear phases at a cloud point temperature do not occurred at a room temperature [33].…”

Section: Phase Separationmentioning

confidence: 99%

Whole cell microbial transformation in cloud point system

Wang

Chen³

2008

J Ind Microbiol Biotechnol

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Cloud point system, consisting of nonionic surfactant in an aqueous solution, has been developed as a novel medium for whole cell microbial transformation. The basic properties of cloud point system including phase separation and solubilization are introduced. The application of cloud point system for extractive microbial transformation is different from that of water-organic solvent two-phase partitioning system or aqueous two-phase system are discussed, which mainly focus on the biocompatibility of microorganism in a cloud point system and a downstream process of microbial transformation in cloud point system with oil-water-surfactant microemulsion liquid-liquid extraction for surfactant recovery and product separation. Finally, examples of whole cell microbial transformation in cloud point systems, especially in situ extraction of moderate polar substrate/product, are also presented.

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Effect of oilfield chemicals on the cloud point of nonionic surfactants

Cited by 62 publications

References 35 publications

Cloud Point and Dye Solubilization Studies of Amphiphilic Drug Solutions: The Effect of Electrolytes and Nonelectrolytes

Cloud Point and Dye Solubilization Studies of Amphiphilic Drug Solutions: The Effect of Electrolytes and Nonelectrolytes

A Cloud Point Study on the Micellar Growth of an Amphiphilic Drug in the Presence of Alcohol and Ionic Surfactant

Whole cell microbial transformation in cloud point system

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