Synthesis of amphiphilic (meth)acrylates with oligo(ethylene glycol) and (or) oligo(propylene glycol) blocks by the esterification of (meth)acrylic acid

Abstract

Thermoresponsive PEG‐based (PEG stands polyethylene glycol) polymers are unique for use in medicine because of their low toxicity, good biocompatibility and biodegradability, but usually more hydrophobic and more toxic comonomers are used to adjust lower critical solution temperature (LCST). A convenient way to overcome this problem and to finely tune LCST is to use alkoxy oligo(ethylene glycol)‐ or alkoxy oligo(propylene glycol) (meth)acrylates as starting comonomers. Here we report on the conditions for the simple and affordable synthesis of methoxy oligo(propylene glycol) (meth)acrylate‐ and methoxy oligo(propylene glycol)‐block‐oligo(ethylene glycol) (meth)acrylate‐based macromonomers with high yields (80%–98.7%) by the acid‐catalyzed esterification of (meth)acrylic acid with alkoxy oligo(alkylene glycols) containing oligo(ethylene glycol) (OEG) and/or oligo(propylene glycol) (OPG) blocks. p‐Toluene sulphonic acid (pTSA), alkyl(C12–C14)benzene sulfonic acid (ABSA) and H2SO4 were used as catalysts. It has been shown that pTSA and ABSA are practically the same in catalytic activity and are superior to sulfuric acid. The reaction orders with respect to catalyst was found to be close to 1 in all cases. It has been shown that the reaction is actually insensitive to the lengths of OEG and OPG blocks, as well as to the structure of the terminal alkyl group, while the esterification of acrylic acid (AA) proceeds much faster compared to methacrylic acid (MAA) one under the same conditions. The influence of temperature on the equilibrium conversions of alcohols was determined, which were found to be 89%–93% for the esterification of AA and 61%–86% for MAA in the temperature range of 60–120°C. A further increase in conversion was achieved by introducing an azeotropic agent (toluene), its optimal concentration was found to be 10%–15%.

High-molecular weight bottlebrushes via continuous flow photoiniferter polymerization of macromonomers

“…The macromonomers, methoxy oligo(ethylene glycol) 8.5 methacrylate (MOEGMA, M n = 500) from Sigma-Aldrich (Moscow, Russia) and alkoxy(C 12 -C 14 ) oligo(ethylene glycol) 6.2 methacrylate (AOEGMA) (Fig. 1) synthesized according to work 49 pentanoic acid (CDTPA) was synthesized according to the procedure. 50 All solvents (toluene, dimethyl sulfoxide, tetrahydrofuran (ACS reagent, ≥99.5%), methylene chloride, acetonitrile (for spectroscopy, ≥99.5%), and hexane (Laboratory Reagent, ≥95%) from Aldrich (Moscow, Russia) were used without purification.…”

“…The macromonomers, methoxy oligo(ethylene glycol) 8.5 methacrylate (MOEGMA, M n = 500) from Sigma-Aldrich (Moscow, Russia) and alkoxy(C 12 –C 14 ) oligo(ethylene glycol) 6.2 methacrylate (AOEGMA) (Fig. 1) synthesized according to work 49 were purified from the inhibitor by passing through basic alumina. Chain transfer agent 4-((((2-carboxyethyl)thio)carbonothioyl)thio)-4-cyanopentanoic acid (CTCPA) was obtained from Boron Molecular, 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanoic acid (CDTPA) was synthesized according to the procedure.…”

Amide-Containing Bottlebrushes via Continuous-Flow Photoiniferter Reversible Addition–Fragmentation Chain Transfer Polymerization: Micellization Behavior

“…The starting monomers were acrylamide, methacrylamide, N-methylacrylamide, and methoxy oligo(ethylene glycol) methacrylate (MOEGM, Mn = 500) from Sigma-Aldrich (Moscow, Russia) and alkoxy(C12–C14) oligo(ethylene glycol) methacrylate (AOEGM) ( Figure 1 ) synthesized following the procedure outlined in [ 63 ]. MOEGM and AOEGM were subsequently purified from an inhibitor by passing through basic alumina.…”