Synthesis of New Sulfobetaine Gemini Surfactants with Hydroxyls and Their Effects on Surface‐Active Properties

Abstract

Sulfobetaine gemini surfactants, bis{[(N‐methyl‐N‐(3‐alkoxy‐2‐hydroxyl) propyl‐N‐(2‐hydroxyl‐3‐sulfonic acid sodium) propyl] methylene} ammonium chlorides (n = 10, 12, 14), were synthesized by etherification, ring‐opening reaction, and quaternization with epichlorohydrin, linear‐saturated alcohol, N,N′‐dimethylethylenediamine, and 3‐chloro‐2‐hydroxypropane sulfonic acid sodium as main raw materials. The structures of the sulfobetaine gemini surfactants with hydroxyls were characterized using Fourier transform infrared spectroscopy (FTIR), 1H‐Nuclear Magnetic Resonance (NMR), mass spectroscopy (MS), and elemental analysis. With increasing length of the carbon chain, the values of the critical micelle concentration (CMC) initially decreased. These compounds exhibit superior surface‐active properties compared to single‐chain sulfobetaine surfactants such as dodecyl dimethyl hydroxyl sulfopropyl betaine surfactants. The efficiency of adsorption at the water/air interface (pC20) of these surfactants is very high. The shorter hydrophobic chain length of sulfobetaine gemini surfactants, the faster the surface tension reduction, and the smaller the aggregation number of sulfobetaine gemini surfactants. The micelle diameter and the maximum wetting angle of pure water drop/air increased, but the maximum wetting angle of water phase/n‐decane decreased with the increase of the hydrophobic chain length. With the increase of the hydrophobic chain length, salinity resistance went up and the corresponding interfacial tension reduced. Their foam volume and foam half‐life were investigated. Our studies have indicated that synthesized gemini surfactants can effectively reduce the oil/water interfacial tension to ultralow interfacial tension of hexane (IFT) (10−3 mN m−1 orders of magnitude) under the conditions of high temperature and high salinity.

Progress in research of sulfobetaine surfactants used in tertiary oil recovery

“…The excellent comprehensive properties of sulfobetaine surfactants have attracted increasing research attention. At present, sulfobetaine surfactants are used in the chemical industry and tertiary oil recovery (Zhou et al, 2018). In the chemical industry, the most commonly used sulfobetaine surfactants are dodecyl hydroxysulfonyl betaine and octadecyl hydroxy‐sulfonyl betaine.…”

“…The sulfonic acid group and internal salt structure of sulfobetaine surfactant determine its stable properties, good temperature and salt tolerance, so it is expected to be used in oil displacement at high‐temperature and high‐salinity reservoirs (Zhou et al, 2017; Zhou, Bu, et al, 2018; Zhou, Chen, et al, 2018; Zhou, Liang, & Jia, 2018; Zhou, Zhang, et al, 2018). At the same time, sulfobetaine surfactants have excellent compatibility which can greatly reduce the chromatographic separation effect (the increase in interfacial tension value is due to the mismatch of polymer and surfactant concentration because of the difference of formation rock adsorption) when it is mixed with nonionic surfactants and/or polymers (Guo et al, 2018; Jiang et al, 2014; Kamal et al, 2016).…”

“…A series of dual hydroxyl sulfobetaine surfactants with different carbon chain lengths (C 8 SB, C 10 SB, C 12 SB, C 14 SB and C 16 SB) were synthesized by using linear saturated alcohol, epichlorohydrin and dimethylamine (Zhou, Bu, et al, 2018; Zhou, Chen, et al, 2018; Zhou, Liang, & Jia, 2018; Zhou, Zhang, et al, 2018). The synthesis routes are shown in Figure 8.…”

“…Gemini surfactants have much better surface activities and more remarkable efficiency than conventional surfactants, which are expected to obviously reduce surface tension, have much smaller cmc values, better aggregation behavior, lower Krafft points, and enhance water solubility (Zhou, Bu, et al, 2018; Zhou, Chen, et al, 2018; Zhou, Liang, & Jia, 2018; Zhou, Zhang, et al, 2018). For Gemini sulfobetaine surfactants, the IFT of oil/water can be ultralow in the presence or absence of a weak alkali (Chen et al, 2018; Jiang et al, 2014; Zhou et al, 2015).…”

Studies on Physicochemical Properties and Aggregation Behavior of Two Pairs of Betaine Surfactants

“…It is well known that the chemical structures of betaine surfactants are a crucial part in determining their physicochemical properties and even their application fields. To obtain comprehensive understanding of betaine surfactants, many studies have been carried out to synthesize novel kinds of betaine surfactants. − Most studies have concentrated on investigating the effect of hydrophobic moieties modifications, − the hydrocarbon chain length, − and the types of hydrophilic headgroups , on physicochemical properties. For example, Kelleppan et al synthesized five long-chain amidopropyl betaines with C18 tailgroups and found that different degrees of unsaturation and branching significantly affect aggregation structures.…”