Dimethyl muconate, (E,E)- → Dimethyl 1,4-cyclohexanedicarboxylate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

In a Parr reactor, a mixture of trans,trans dimethyl muconate (6.13 g, 36.0 mmol) and diglyme (120 ml, 0.30 M) is heated to 165° C. for 24 hours under ethylene pressure (pRT=259 psi (1.79 MPa)). After cooling to room temperature, the weakly yellow, clear solution is diluted using diglyme to 200 ml in a volumetric flask, transferred into a round-bottom flask equipped with a magnetic stirring bar, and catalytic palladium on carbon (Pd/C) is added (356 mg of Johnson-Matthey 5 percent Pd/C #6, 0.2 mole percent) at room temperature. The flask is equipped with a reflux condenser, fitted gas dispersion tube, and internal Temperature probe. Under N2 flow (190 ml/min) and stirring (190 rpm) the mixture is heated to reflux (Tmax, observed=169° C.) while samples were taken at appropriate intervals (t=0.0, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0 h) to monitor the progress of the reactions occurring. Rapid (t≦1 h) disappearance of the dimethyl cyclohex-2-ene-1,4-dicarboxylate, □2, 2-ene is observed concurrent with some material undergoing tautomerization to its thermodynamically more stable isomer (dimethyl cyclohex-1-ene-1,4-dicarboxylate, □1, 1-ene), while also the desired oxidation/dehydrogenation/aromatization product dimethyl terephthalate (DMT) and some reduced material (dimethyl cyclohexane-1,4-dicarboxylate CHa) are formed. After 8 hours reaction time, 77 percent DMT, 17 percent cyclohexane, and 5 percent tautomer are present. The graph of FIG. 2 shows the concentration of materials at various time intervals.

Herkunft & Nachweise