No abstract

This short paper aims to clarify the main factor controlling overall transesterification rate of vegetable oil (triglycerides) with methanol catalyzed by homogeneous acid catalyst. In this reaction system, methanol droplets are dispersed in oil continuous phase. Most of the catalyst is existing in methanol droplets. The authors formulated a simultaneous diffusion-reaction model by focusing on the following processes: (1) dissolving of oil into methanol droplets at the oil-methanol interface, (2) inward diffusion of oil in methanol droplets, and (3) simultaneous transesterification of oil with the inward diffusion. In order to prove this model, firstly, the intrinsic transesterification kinetics were determined in methanol/oil/2-butanone/sulfuric acid system at 298, 308, and 323 K. 2-Butanone and sulfuric acid were used as a co-solvent and a catalyst, respectively. Secondly, transesterification of oil with methanol catalyzed by sulfuric acid was carried out in ordinary two-phase system at 298, 308, and 323 K. The authors successfully simulated the two-phase reaction results from the homogeneous kinetics by applying the model developed in this paper. It was found that the overall transesterification rate is controlled by the intrinsic kinetics.

Encapsulation of both 3,4-ethylenedioxythiophene (EDOT) and terthiophene (TTh) into a cyclodextrin-based metalorganic framework (CD-MOF) was successfully achieved upon use of an adsorption technique. The average amount of EDOT introduced into the CD-MOF was calculated to be 4.3 molecules per hydrophilic nanopore. On the other hand, from the relationship between the molecular size of TTh and the nanopore volume, TTh was evaluated and found to be mostly isolated in each hydrophobic nanopore of the CD-MOF. Co-oligomerization of EDOT and TTh in a CD-MOF was initiated by exposure to I 2 vapor and subsequent heating at 80°C for 6 h. A trace amount of the co-oligomers consisting of two TTh molecules and four or ve EDOT molecules was detected by using matrix-assisted laser desorption ionization time-ofight mass spectrometry (MALDI-TOF MS). The chemical structure of the co-oligomer was considered to be TTh bound at both ends of the EDOT tetramer or pentamer.