Clean Synthesis of Epoxidized Tung Oil Derivatives via Phase Transfer Catalyst and Thiol–ene Reaction: A Detailed Study

Abstract

Introducing renewable tung oil into the environment-friendly plasticizer production via clean and efficient strategies to substitute toxic dioctyl phthalate (DOP) holds potential application value to reduce pollution and improve human health. Here we reported two strategies for production of epoxy plasticizers via phase transfer catalyst and thiol−ene reaction using tung oil as starting material. Phase transfer catalyst (C 17 H 30 ClN) 3 O 40 PW 12 •xH 2 O was synthesized and used in acid-free catalytic process. The optimum epoxidation reaction and thiol−ene reaction parameters were investigated. Epoxy value of the obtained epoxy tung oil methyl ester (ETM) and tung-oil-based epoxy plasticizer (TEP) reached 4.9% and 5.2%. Poly(vinyl chloride) (PVC) films plasticized with ETM and TEP showed better thermal stability and solvent resistance than DOP. Plasticizing efficiency of ETM and TEP reached 104.1% and 101.5%, respectively. In conclusion, epoxy plasticizers were produced in sustainable and environmentally friendly strategies using tung oil as raw material and can completely replace toxic DOP used in flexible PVC films.

Plasticizers Derived from Biomass Resources: A Short Review

“…Our group synthesized a series of epoxidized castor oil polyol esters, epoxidized soybean oil polyol esters, and epoxidized tung oil methyl ester via alcoholysis and epoxidation, and investigated their plasticizing effect on PVC films [13,21,22,23]. Figure 2 shows the synthesis route of epoxidized castor oil polyol ester.…”

An efficient plasticizer based on waste cooking oil: Structure and application

“…PVC is brittle, and the T g value was approximately 82 C according to some reports. 15,16 It could be seen from the figure that the T g value of PVC drops from 20.9 C to 12.5 C with the increase of AC-FAME-TAE. In addition, by the comparison of D-60, E-60, and A − 60, the T g value of E-60 was the lowest among these PVC samples.…”

“…34 As can be seen from the spectra of FAME and EFAME, the stretching vibration peak of unsaturated C H at 3008 cm −1 was disappeared and the peak of the epoxy bond (C O C) at 840 cm −1 was appeared, indicating that the double bond in the FAME was converted into epoxy bond. 16,[35][36][37] After the ring opening reaction, the epoxy bond peak at 840 cm −1 disappeared, while the hydroxyl peak at 3521 cm −1 and the vibration peak of benzene ring skeleton at 1574 and 1609 cm −1 appeared, showing that a ring opening reaction of the epoxy compound occurred. The change of functional groups in the fourth step of acetylation could be observed clearly from the FT-IR spectra.…”

“…The main structure of vegetable oil is triglyceride, and there may be unsaturated double bonds in the fat chain, which provides the possibility of structural modification of vegetable oil. Actually, many kinds of vegetable oil such as soybean oil, [13][14][15] tung oil, [16][17][18] castor oil, 19,20 cardanol, 21 and palm oil 22,23 could be used as raw materials for bio-based plasticizers. Among these vegetable oil-based plasticizers, some of them have excellent plasticizing properties, and some have functional properties such as flame retardant, non-migration, etc.…”

Study on Toughening Phenolic Foams in Phosphorus-Containing Tung Oil-Based Derivatives

“…The main component of tung oil is tung acid glyceride (octadecyl conjugated-9,11,13-trienoic acid glyceride), which accounts for 77-82% of the content of tung oil [20]. The conjugated triene bonds and ester group exhibit strong reactivity and can undergo various reactions including amidation, transesterification, Friedel-Crafts, Diels-Alder, epoxidation, and click reactions [21]. Through these reactions, tung oil has been developed into a range of products, including polyurethane foams [2], epoxy resins [22], unsaturated co-esters [23], and plasticizers [24].…”