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Dimethyl Oxalate (dimethyl + oxalate)

Distribution by Scientific Domains
Chemistry75%

Selected Abstracts

Formation of 2,6-Dioxabicyclo[3.3.0]-octa-3,7-dienes or Multiply Substituted o-Benzoquinones from Reactions of 1,4-Dilithio-1,3-dienes with Dimethyl Oxalate.

CHEMINFORM, Issue 5 2005
Guoliang Mao
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Transesterification of dimethyl oxalate with phenol over TiO2/SiO2: Catalyst screening and reaction optimization

AICHE JOURNAL, Issue 12 2008
Xia Yang
Abstract Physicochemical properties of silica-supported titanium oxide catalysts as well as their performances for transesterification of dimethyl oxalate (DMO) with phenol to methyl phenyl oxalate (MPO) and diphenyl oxalate (DPO) have been investigated systematically. Various wt % of TiO2 were loaded on SiO2 by a two-step wet impregnation method. The surface properties of TiO2/SiO2 catalysts were explored by various characterization techniques (BET, SEM, ICP, XPS, XRD, FTIR of pyridine adsorption, and NH3 -TPD). Catalytic performances of TiO2/SiO2 catalysts were found to be strongly dependent on TiO2 dispersion and surface acidity. Monolayer dispersion capacity of TiO2 on silica was estimated to be about 4.0 TiO2 molecules per nm2 (SiO2) and no crystalline TiO2 was detected at TiO2 loading less than 12 wt %. FTIR and TPD analysis suggested that weak Lewis acid sites on the surface of TiO2/SiO2 were responsible for their unique selectivity to the target products, MPO and DPO. An optimization of reaction conditions for the transesterification of DMO with phenol was performed over 12 wt % TiO2/SiO2 calcined at 550°C. In addition, we studied the disproportionation reaction from MPO to DPO via a catalytic distillation process, which is highly efficient to promote formation of the desired DPO. © 2008 American Institute of Chemical Engineers AIChE J, 2008 [source]

Poly(ester-urethane)s synthesized using polyoxalate diols

POLYMER ENGINEERING & SCIENCE, Issue 2 2005
Hideho Tanaka
Amorphous poly(ester-urethane)s (PEUs) were synthesized by reacting polyoxalate diols (PODs), which are oligoester diols prepared from condensation polymerization of dimethyl oxalate (DMO) and alkane diols, with 4, 4,-diphenylmethane diisocyanate (MDI) and propylene diamine (PDA), a chain extender. Their structure,property relationships were studied, mainly focused on effects of molecular weight and alkylene chain length of the POD. The synthesized PEUs were buried in compost soil at 30°C and incubated to conveniently evaluate their biodegradability. Their hydrolytic characteristics were also examined, and what made poly(oxalate-urethane) (POU) biodegradable was discussed. Poly(oxalate carbonate-urethane) (POCU), which can be produced adding a polycarbonate diol (PCD) into the POD and then copolymerizing them with DMO, provided biodegradable polyurethanes with mechanical properties appropriate for practical uses. In addition, the microstructure of these copolyurethanes was characterized. POLYM. ENG. SCI., 45:163,173, 2005. © 2005 Society of Plastics Engineers. [source]