Synthesis of new extended surfactants containing a xylitol polar group

138

132

The minimum interfacial tension occurrence along a formulation scan at the so-called optimum formulation is discussed to be related to the interfacial curvature. The attained minimum tension is inversely proportional to the domain size of the bicontinuous microemulsion and to the interfacial layer rigidity, but no accurate prediction is available. The data from a very simple ternary system made of pure products accurately follows the correlation for optimum formulation, and exhibit a linear relationship between the performance index as the logarithm of the minimum tension at optimum, and the formulation variables. This relation is probably too simple when the number of variables is increased as in practical cases. The review of published data for more realistic systems proposed for enhanced oil recovery over the past 30 years indicates a general guidelines following Winsor’s basic studies concerning the surfactant–oil–water interfacial interactions. It is well known that the major performance benefits are achieved by blending amphiphilic species at the interface as intermolecular or intramolecular mixtures, sometimes in extremely complex formulations. The complexity is such that a good knowledge of the possible trends and an experienced practical know-how to avoid trial and error are important for the practitioner in enhanced oil recovery.

Section: Trends To Improve Performancementioning

confidence: 99%

How to Attain an Ultralow Interfacial Tension and a Three‐Phase Behavior with a Surfactant Formulation for Enhanced Oil Recovery: A Review. Part 2. Performance Improvement Trends from Winsor's Premise to Currently Proposed Inter‐ and Intra‐Molecular Mixtures

Salager

Forgiarini

Márquez

et al. 2013

138

132

“…The term extended surfactants refers to the fact that the propylene oxide group introduces a gradual transition between the lipophilic alkyl group and the hydrophilic group, thus ''extending'' the reach of these groups into the oil and aqueous phases [10]. Extended surfactant chemistries are diverse and include alkyl-PPO-polyethylene oxide (PEO)-sulfate, carboxylates and carbohydrate head groups [11][12][13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

On the Characteristic Curvature of Alkyl‐Polypropylene Oxide Sulfate Extended Surfactants

Hammond

Acosta

2011

The hydrophobicity of alkyl-polypropylene oxide sulfate surfactants was evaluated via their characteristic curvature (Cc) using the hydrophilic-lipophilic difference (HLD) framework. A close examination of the relationship between the molecular structure of the surfactants considered (structure of the alkyl group and the number of propylene oxide groups in each surfactant) and their Cc led to a group contribution model that, for the first time, takes into consideration the geometry of the alkyl tail group. Based on this group contribution model, branching at the C2 (beta-carbon) position of the alkyl group produces the largest increase in characteristic curvature. This observation is consistent with the notion that the Cc is associated with the packing factor for anionic surfactants. Branching at the C2 position tends to produce cylindrical or inverse cone shape packing, typical of more hydrophobic (positive Cc) surfactants. This study also confirms previous observations that, different from conventional anionic surfactants, the phase behavior of alkyl polypropylene oxide sulfates is less sensitive to electrolyte concentration and that these formulations turn hydrophobic with increasing temperature, akin to the behavior of nonionic surfactants.

“…In recent years, extended surfactants, with an intermediate polarity group (propylene oxide (PO) and/or ethylene oxide (EO) groups) inserted between the hydrophilic head and hydrophobic tail, have been investigated in many applications [1][2][3][4][5][6][7][8][9]. Due to their unique molecular structure, extended surfactants not only exhibit an increase in the tail length, but also offer a smoother transition between the hydrophilic and hydrophobic phases resulting in a more suitable environment for solubilizing both hydrophilic and lipophilic solutes [10,11].…”

Section: Introductionmentioning

confidence: 99%

Ethoxy Carboxylate Extended Surfactant: Micellar, Adsorption and Adsolubilization Properties

Arpornpong

Charoensaeng

Sabatini

et al. 2010

The micellar, adsorption, and adsolubilization properties of a novel ethoxy carboxylate extended surfactant are measured and compared to an extended sulfate surfactant. The critical micelle concentration (CMC) of the ethoxy carboxylate extended surfactant is measured to be 0.02 mM while it is 0.07 mM for the extended sulfate surfactant. Adsorption and adsolubilization studies are carried out on alumina oxide surfaces. The extended sulfate surfactant has a higher maximum adsorption capacity onto the aluminum than the ethoxy carboxylate extended surfactant (0.47 vs. 0.14 mmol/g, respectively). For adsolubilization, the extended sulfate surfactant shows a slightly higher phenanthrene adsolubilization compared to the ethoxy carboxylate extended surfactant (log K adm of 6.15 vs. 5.71, respectively). In contrast, for solubilization, the ethoxy carboxylate extended surfactant exhibits higher phenanthrene solubilization capacities than the extended sulfate surfactant (log K mic of 5.61 vs. 5.42, respectively). Relative to surfactant loss from the solid surface, the ethoxy carboxylate extended surfactant shows a higher desorption capacity as compared to the extended sulfate surfactant. From these measurements, the ethoxy carboxylate extended surfactant has better properties for micellar applications (lower CMC, higher K mic ), while the extended sulfate surfactant has better properties for admicellar applications (higher q max and K adm values, and less desorption).