Microwave-assisted NaHSO₄-catalyzed synthesis of ricinoleic glycol ether esters

<p>The synthesis of several ricinoleic acid glycol ether esters by high-pressure microwave radiation is described. Ricinoleic acid which is from castor oil reacted fastly with glycol ethers in the presence of NaHSO₄ · H₂O and dichloromethane (DCM) in special microwave reactor. The influences of reaction factors such as catalyst and solvent type, reaction temperature, and time were investigated and the optimal reaction conditions were obtained. The activity of catalyst had a higher performance up to the 10th cycle and the excellent values of turnover numbers and turnover frequency were obtained. Compared with the traditional esterification in reflux heating systems., the microwave-assisted process has many advantages such as shorter reaction time, less side effects, higher yield, which is a great potential for the development of green chemistry.</p

Synthesis of Gallic Acid-Derived Plasticizers for Polyvinyl Chloride Featuring Excellent Plasticization, Thermo-Stability, and Migration Resistance

The development of a facile and environmental strategy for manufacturing a natural aromatic-derived plasticizer for poly(vinyl chloride) (PVC) featuring excellent plasticization, UV-shielding, and thermostability, together with migration resistance, is still a challenge. Herein, a series of gallic acid-derived polypropylene glycol monomethyl ether esters with natural aromatic rings (TGPME-n, n = 1, 2, or 3 referring to the number of methylethoxy units in the structure of TGPME-n) were developed as plasticizers for PVC via the simple esterification of gallic acid with polypropylene glycol monomethyl ether and sequent etherification with epichlorohydrin in a one-pot process without any HCl generation. Extensive experiments showed that the performances of PVC blended with TGPME-n were highly dependent on the number of methylethoxy units from TGPME-n, where the performances of PVC plasticized by TGPME-n with more methylethoxy units were better than those of TGPME-n bearing one. Benefiting from the strong interaction of aromatic and polar groups (epoxy, ethoxy, and ester groups) in TGPME-n with a PVC skeleton, plasticization, low temperature resistance, thermal stability, transparency, and UV-shielding as well as migration resistance of PVC plasticized by TGPME-3 with maximum methylethoxy units were superior to those of PVC blended with dioctyl phthalate (DOP), implying that TGPME-3 could be used as an attractive alternative to totally replace the toxic DOP. This study provides a simple and feasible strategy to fabricate a highly efficient natural aromatic-derived plasticizer for the PVC industry