A tandem strategy for low-cost co-production of dimethyl 2,5-furandicarboxylate and dimethyl malonate

Aiming at efficient production of high-value green chemicals, this study developed a novel tandem process for co-production of dimethyl 2,5-furandicarboxylate (FDME) and dimethyl malonate (DMM) using inexpensive bulk chemicals such as 2-methylfuran, acetic anhydride and dimethyl carbonate (DMC) as feedstock. This process achieves a 100% conversion of 2-methylfuran (MF) and a 98.6% selectivity for 5-methyl-2-acetylfuran (2,5-AMF) via specific C5-acetylation over a lactic acid-modified Hβ zeolite catalyst in the fixed-bed reactor, maintaining stable activity through nine consecutive cycles. Under anaerobic conditions, weakly basic Zr(OH)₄ mediates the oxygen insertion coupling of 5-methyl-2-acetylfuran (2,5-AMF) with DMC, resulting in the co-production of methyl 5-methyl-2-furoate (5,2-MMFCA, 100% yield) and DMM (63.7% yield). Subsequent oxidation using a Co-Br-Mn-acetic acid system yields 5-(methoxycarbonyl)furan-2-carboxylic acid (MFDCA, 92% yield), which spontaneously separates as 99% pure crystals out from the acetic acid medium, dramatically simplifying the conventional oxidation-purification workflow. In the final esterification step, the oxidation product is reacted with methanol in the presence of a heterogeneous acid catalyst (Amberlyst 15), yielding the target product, dimethyl 2,5-furandicarboxylate (FDME, 100% yield). Notably, this integrated route couples FDME synthesis with DMM co-production, significantly enhancing overall economic viability. Techno-economic analysis reveals that, factoring in the revenue from DMM co-production (market price: $3500 per ton), the net production cost of FDME is reduced to $623.8 per ton. This cost approaches parity with that of petroleum-derived terephthalic acid (TPA), demonstrating exceptional industrial potential.