Synthesis and Characterization of Acetylated and Stearylyzed Soy Wax

A solvent-free synthesis method was developed for incorporating acetyl and hydroxy groups and long-chain fatty alcohol in fully hydrogenated soybean oil (FHSO) to produce a wax to be used as beeswax or paraffin substitutes in packaging and coatings. FHSO was reacted with stearyl alcohol and triacetin at 140–150 °C for 2 h, and the reaction was catalyzed by 0.018 wt% sodium methoxide. The addition of alcohol increased the reaction yield and the melting point of the final wax by 9 and 25 %, respectively, compared to the wax produced from the reaction of FHSO and triacetin alone. The effects of the ratio of stearyl alcohol and triacetin to FHSO on the textural properties of the modified soy wax were examined. The reaction of FHSO:stearyl alcohol:triacetin at a molar ratio of 9:7:15 produced a wax that was 1.2 and 2.4 times harder than beeswax and FHSO, respectively, but 1.7 times softer than a commercial grade paraffin wax. This modified soy wax comprised 75 % acetylated glycerol esters including diacetylmonoacylglycerides (31 %), monoacetylmono- (12 %) and diacylglycerides (32 %), and 25 % non-acetylated molecules including wax ester (14 %), and acylglycerides (11 %). The acetylated soy wax had high cohesiveness and did not break under compression.