94-60-0Relevant articles and documents
Solvent-driven isomerization of: cis, cis -muconic acid for the production of specialty and performance-advantaged cyclic biobased monomers
Carraher, Jack M.,Carter, Prerana,Cochran, Eric W.,Forrester, Michael J.,Pfennig, Toni,Rao, Radhika G.,Shanks, Brent H.,Tessonnier, Jean-Philippe
, p. 6444 - 6454 (2020/11/09)
The quest for green plastics calls for new routes to aromatic monomers using biomass as a feedstock. Suitable feedstock molecules and conversion pathways have already been identified for several commodity aromatics through retrosynthetic analysis. However, this approach suffers from some limitations as it targets a single molecule at a time. A more impactful approach would be to target bioprivileged molecules that are intermediates to an array of commodity and specialty chemicals along with novel compounds. Muconic acid (MA) has recently been identified as a bioprivileged intermediate as it gives access to valuable aliphatic and cyclic diacid monomers including terephthalic acid (TPA), 1,4-cyclohexanedicarboxylic acid (CHDA), and novel monounsaturated 1,4-cyclohexenedicarboxylic acids (CH1DA, CH2DA). However, accessing these cyclic monomers from MA requires to first isomerize biologically-produced cis,cis-MA to Diels-Alder active trans,trans-MA. A major impediment in this isomerization is the irreversible ring closing of MA to produce lactones. Herein, we demonstrate a green solvent-mediated isomerization using dimethyl sulfoxide and water. The mechanistic understanding achieved here elucidates the role of low concentrations of water in reducing the acidity of the system, thereby preventing the formation of lactones and improving the selectivity to trans,trans-MA from less than 5% to over 85%. Finally, a Diels-Alder reaction with trans,trans-MA is demonstrated with ethylene. The monounsaturated cyclic diacid obtained through this reaction (CH1DA) can be converted in a single step into TPA and CHDA, or can be directly copolymerized with adipic acid and hexamethylenediamine to tailor the thermal and mechanical properties of conventional Nylon 6,6.
Birch-Type Photoreduction of Arenes and Heteroarenes by Sensitized Electron Transfer
Chatterjee, Anamitra,K?nig, Burkhard
supporting information, p. 14289 - 14294 (2019/08/30)
The direct reduction of arenes and heteroarenes by visible-light irradiation remains challenging, as the energy of a single photon is not sufficient for breaking aromatic stabilization. Shown herein is that the energy accumulation of two visible-light photons allows the dearomatization of arenes and heteroarenes. Mechanistic investigations confirm that the combination of energy-transfer and electron-transfer processes generates an arene radical anion, which is subsequently trapped by hydrogen-atom transfer and finally protonated to form the dearomatized product. The photoreduction converts planar aromatic feedstock compounds into molecular skeletons that are of use in organic synthesis.
Synthesis of gasoline and jet fuel range cycloalkanes and aromatics from poly(ethylene terephthalate) waste
Tang, Hao,Li, Ning,Li, Guangyi,Wang, Aiqin,Cong, Yu,Xu, Guoliang,Wang, Xiaodong,Zhang, Tao
supporting information, p. 2709 - 2719 (2019/06/03)
For the first time, gasoline and jet fuel range C7-C8 cycloalkanes and aromatics were selectively synthesized by the alcoholysis of poly(ethylene terephthalate) (PET) waste, followed by solvent-free hydrogenation and hydrodeoxygenation (HDO). It was found that methanol is highly reactive for the alcoholysis of PET waste. In the absence of any catalyst, a high yield of dimethyl terephthalate (97.3%) was achieved under mild conditions (473 K, 3.5 h). Dimethyl terephthalate exists as a solid and can be automatically separated from methanol with a decrease in temperature. Subsequently, dimethyl terephthalate was liquefied to dimethyl cyclohexane-1,4-dicarboxylate by hydrogenation over noble metal catalysts. Among the investigated catalysts, Pt/C exhibited the highest activity. Finally, the dimethyl cyclohexane-1,4-dicarboxylate as obtained was further hydrodeoxygenated to C7-C8 cycloalkanes and aromatics that can be used as gasoline or additives to improve the densities (or volumetric heat value) and sealabilities of current bio-jet fuels. Bimetallic Ru-Cu/SiO2 was found to be a promising HDO catalyst. According to the characterization results, the excellent HDO performance of Ru-Cu/SiO2 can be explained by the formation of smaller Ru-Cu alloy particles during the catalyst preparation. In real applications, dimethyl cyclohexane-1,4-dicarboxylate can also be simultaneously hydrodeoxygenated with biomass derived oxygenates to produce jet fuel with a suitable content of cycloalkanes and aromatics.
