Synthesis of a new bifunctional molecule based on castor oil and CO₂ useful for polyurethanes

Abstract

A new bifunctional biobased molecule, the carbonated methyl ester of ricinoleic acid maleate (CME‐RAM), useful for polyurethanes, was obtained from castor oil and CO2. This molecule bears carbonate and maleate functionalities that can participate, respectively, in aza‐Michael and aminolysis reactions. Maleate moieties are strong Michael acceptors and they were introduced into the fatty molecule using mild conditions. The synthetic steps include maleinization of castor oil followed by the simultaneous esterification and transesterification at 60°C. The subsequent stages were the epoxidation with acidic resins and the carbonation with CO2. The best results for epoxidation were obtained using Amberlite IR‐120 as catalyst at 48°C (84% conversion of double bonds). The carbonation of the oxirane ring with CO2 at 130°C, 6 MPa CO2 and 6 h reaction afforded 98% conversion of epoxides. It was demonstrated that aza‐Michael reaction of maleate groups was faster than aminolysis of carbonate groups, using hexylamine as a model molecule. CME‐RAM was oligomerized with ethylenediamine and used in the formulation of a conventional rigid polyurethane. Petrochemical polyol and isocyanate can be partially replaced by this bio‐based oligomer, producing a rigid material with a high percentage of green component and good mechanical properties.

A fully bio‐based monomer derived from undecylenic acid, glycerol, and CO2 useful for the synthesis of polyhydroxyurethanes

“…However, the swelling is higher in Amberlite IR‐120 due to lower content of divinylbenzene (DVB) (8%) in comparison with Amberlyst 15 (20% DVB). In comparison with other studies with vegetable oils, a longer reaction time was required for the epoxidation of UA triglyceride under similar reaction conditions 15,28–32 . These differences in the reactivity of the internal and terminal double bonds have been observed by other authors and they have been justified based on the inductive effects of the alkyl groups.…”

“…In comparison with other studies with vegetable oils, a longer reaction time was required for the epoxidation of UA triglyceride under similar reaction conditions. 15,[28][29][30][31][32] These differences in the reactivity of the internal and terminal double bonds have been observed by other authors and they have been justified based on the inductive effects of the alkyl groups. That is, the terminal double bonds have a less electrophilic character in relation to the internal double bonds, which decreases the epoxidation rate.…”

“…UA can be obtained from castor oil through a commercial process 13 . Glycerol and CO 2 are recognized as inexpensive and renewable building blocks 14,15 . The process has not been reported before for the synthesis of a carbonated triglyceride of UA.…”

Biobased, Reprocessable Non-isocyanate Polythiourethane Networks with Thionourethane and Disulfide Cross-Links: Comparison with Polyhydroxyurethane Network Analogues

“…In view of the drive toward sustainable and green materials, there is substantial and increasing interest in exploring renewable NIPU and NIPTU materials as replacements for petroleum-based PU and PU-like materials. Numerous studies have reported on biobased PHUs synthesized or capable of being synthesized from unsaturated raw materials like epoxidized soybean oil, 37,60,61 epoxidized castor oil, 62,63 or other renewable materials like limonene, 64 lignin, 65 and furfural. 66 However, reports on biobased NIPTUs are extremely rare; we have found only one study reporting on a biobased NIPTU, which was derived from eugenol or clove oil, 49 a compound that is widely used in the food industry.…”