Quaternary ammonium ionic liquid salts (QAILs) are well known as synergists for kinetic hydrate inhibitor (KHI) polymers such as poly(N-vinyl caprolactam) (PVCap). Earlier work showed that branching of the pentyl tails of tetra(n-pentyl)ammonium bromide to make isohexyl groups and tert-heptyl groups gave a significant improvement in the synergistic KHI performance. We have now evaluated in more detail the KHI performance of tris(tert-heptyl)-N-pentyl-1-ammonium bromide (tris(tert-heptyl)PeAB) or tris(tert-heptyl)-N-propyl-1-ammonium bromide (tris(i-heptyl)PrAB) blended with poly(N-vinyl caprolactam) (PVCap) in steel rocking cells at 130 bar. Due to tris(tert-heptyl)PeAB being sparingly soluble in water we used a water–gas–decane system in order to get this compound dissolved in the fluids. These QAILs were also compared to the known QAILs, tetra(n-butyl)ammonium bromide (TBAB), tetra(n-pentyl)ammonium bromide (TPAB), tetra(n-hexyl)ammonium bromide (TnHexAB), tetra(isohexyl)ammonium bromide (TiHexAB), tetra(n-heptyl)ammonium bromide (TnHepAB), and hexa-n-butylguanidinium chloride (n-Bu6GuanCl),. Under constant cooling test conditions it was found that both tert-heptyl-based QAILs as well as TiHexAB and n-Bu₆GuanCl gave particular good synergistic performance results. To further differentiate the ranking of these QAIL synergists, we also conducted long-term isothermal KHI performance tests on the best synergists. When PVCap was mixed with tris(tert-heptyl)PeAB it gave better performance than when mixed with TPAB, TiHexAB, or n-Bu₆GuanCl in tests at two different isothermal test conditions. These results highlight the excellent synergy of tert-heptylated quaternary ammonium salts and that sparingly water-soluble but oil-soluble quaternary ammonium salts, with the correct functional groups, can still be good synergists for KHI polymers such as PVCap.

中文翻译：

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高压和油基体系中叔庚基季铵盐与聚（N-乙烯基己内酰胺）动力学水合物抑制剂的协同作用

季铵离子液体盐（QAIL）是众所周知的动力学水合物抑制剂（KHI）聚合物（例如聚N-乙烯基己内酰胺）（PVCap）的增效剂。较早的工作表明，四（正戊基）溴化铵的戊基尾部分支形成异己基和叔庚基可使KHI的协同性能显着提高。现在我们已经更详细地评估了三（叔庚基）-N-戊基-1-溴化铵（三（叔庚基）PeAB）或三（叔庚基）-N-丙基-1-铵的KHI性能溴化物（三（异庚基）PrAB）与聚（N-乙烯己内酰胺（PVCap）在130 bar的钢制摇室中。由于三（叔庚基）PeAB微溶于水，因此我们使用水-气-癸烷体系以使该化合物溶解在流体中。还将这些QAIL与已知的QAIL，四（正丁基）溴化铵（TBAB），四（正戊基）溴化铵（TPAB），四（正己基）溴化铵（TnHexAB），四（异己基）进行了比较溴化铵（TiHexAB），四（正庚基）溴化铵（TnHepAB）和六正丁基氯化胍（n- Bu6GuanCl）。在恒定的冷却测试条件下，发现基于叔庚基的QAIL以及TiHexAB和ñ -Bu ₆ GuanCl了特别良好的协同性能结果。为了进一步区分这些QAIL增效剂的排名，我们还对最佳增效剂进行了长期等温KHI性能测试。在两个不同的等温测试条件下，将PVCap与三（叔庚基）PeAB混合时，其性能优于与TPAB，TiHexAB或n- Bu ₆ GuanCl混合时。这些结果突出了叔庚基化季铵盐的优异协同作用，并且具有正确官能团的微溶于水但油溶性季铵盐仍然可以是KHI聚合物（如PVCap）的良好增效剂。