Structural Assignment of Commercial Polyisobutylene Succinic Anhydride‐based Surfactants

Abstract

Concentration of the surface active agents in industrial products is a common source of error. In order to compare the efficiency of a number of polyisobutylene succinic anhydride (PIBSA) based surfactants, their concentration needs to be determined with a fair degree of accuracy. Industrial samples of the monoethanolamine adduct of PIBSA (PIBSA-MEA) concentrate were used for chromatographic separation of the functionalized surfactant from the sample matrix. Complete spectroscopic assignments were based on detailed analysis of all the precursors and of the purified mixture of structural isomers. The structures of the double bond isomers were consistent with the expected addition products of the classic Alderene reaction-derived PIBSA. The carbon-carbon connectivity of the succinamide head group to the bulky polymer tail of PIBSA-MEA was more complicated than previously thought, pointing towards regioselectivity in the nucleophilic substitution of PIBSA. By analogy, further structural assignments of two other surfactants, branded as PIBSA-IMIDE and PIBSA-UREA were made from the spectroscopic data recorded on crude industrial samples. Detailed nuclear magnetic resonance (NMR) assignments for all three surfactants reported here were utilized to develop a semi-quantitative 13 C-NMR based method for the estimation of the amount of the functionalized surfactant relative to the total PIB content in the industrial concentrates. The results highlight common sources of structure-and concentration-dependent errors in high internal phase emulsion formulations.

Characterization of Polyisobutylene Succinic Anhydride (PIBSA) and Its PIBSI Products from the Reaction of PIBSA with Hexamethylene Diamine

“…PIBSA molecules are an essential component in the preparation of PIBSI dispersants used as engine oil additives. Since the properties of PIBSI dispersants are a result of their chemical architecture, which is itself a direct consequence of the chemical composition of the PIBSA starting material, the characterization of PIBSA samples has been the focus of intense research [ 8 , 23 , 24 , 37 , 38 , 39 , 40 , 41 , 42 ]. Despite the numerous challenges complicating the characterization of PIBSA samples [ 19 ], this study provides a protocol that can be implemented to determine the weight fraction w PIB of unmaleated PIB chains in a PIBSA sample by analyzing the GPC traces obtained with a DRI detector of PIBSA–H( X ) reaction mixtures obtained from the reaction between different amounts of PIBSA and HMDA.…”

Polyisobutylenes with Controlled Molecular Weight and Chain-End Structure: Synthesis and Actual Applications

“…It is quite likely that isomeric PIB-SA is able to react with the second molecule of MA. However, the products of the Alder-ene reaction of isomeric PIB-SA with MA were not detected during thorough analysis of the commercial sample of PIB-SA, whereas both isomers of ‘conventional’ PIB-BSA were detected [ 134 ].…”