Synthesis of adiponitrile from dimethyl adipate and ammonia in the vapor-phase over niobium oxide

Abstract

An environmentally benign route leading to adiponitrile (ADN), a nylon-6,6 intermediate, was achieved by direct vapor-phase nitrilation of dimethyl adipate (DMA) with ammonia (NH3) in a fixed-bed reactor. The challenges...

Adjustment of W–O–Zr Boundaries Boosts Efficient Nitrilation of Dimethyl Adipate with Ammonia on WOx/ZrO2 Catalysts

“…The adsorption state of esters on the catalyst surface and the confirmation of active sites were rarely reported. Meanwhile, it is worthy to note that the unsatisfied performance of WO 3 in the conversion of ester functionality 14 was consistent with Auroux's study (8% for lauric acid methyl ester). 16 In the same work, 16 a quantitative yield of lauronitrile could be reached on the amphoteric ZrO 2 .…”

“…The hydrocyanation of butadiene accounts for the most efficient route, leading to ADN, of which the market share records about 65%. , The rest two pilot routes include electrolytic dimerization of acrylonitrile , and ammoniation of adipic acid with ammonia (NH 3 ) . During the past decades, significant efforts have been dedicated to developing novel routes with attempts to address the issues suffered by the existing production technology, including either the toxicity of raw materials or high energy consumption. − In this domain, China TianChen Engineering Corporation Ltd. and we independently reported the direct transformation of dimethyl adipate (DMA) to ADN by patents. , Further details of such a protocol were obtained from the recent two reports by our group, , wherein WO 3 displays excellent nitrile selectivity but low single-pass conversion. It thus partially terminates at the intermediate product of methyl 5-cyanopentanoate (MCP), corresponding to the feature of a tandem reaction .…”

“…7−11 In this domain, China TianChen Engineering Corporation Ltd. and we independently reported the direct transformation of dimethyl adipate (DMA) to ADN by patents. 12,13 Further details of such a protocol were obtained from the recent two reports by our group, 14,15 wherein WO 3 displays excellent nitrile selectivity but low single-pass conversion. It thus partially terminates at the intermediate product of methyl 5-cyanopentanoate (MCP), corresponding to the feature of a tandem reaction.…”

“…It thus partially terminates at the intermediate product of methyl 5-cyanopentanoate (MCP), corresponding to the feature of a tandem reaction. 14 Meanwhile, only a few improvements were made in the reactivity by fabricating the catalyst from carbon-encapsulated oxygen-deficient WO x<3 . 15 In fact, the gas-phase nitrilation of carboxylic monoesters with NH 3 catalyzed by non-noble metal oxides received much attention, considering both the availability of raw materials and the environmental benignity of the process.…”

Chemoselective nitrilation of dimethyl adipate with ammonia over carbon encapsulated WOx catalysts under continuous flow conditions

“…As a preliminary result on suitable metal oxides in our lab, 20 the acidic WO 3 exhibits a moderate conversion of DMA (C DMA : 61.0%) with relatively satisfactory nitrile selectivity (S ADN+MCP : 77.9%) toward a combination of ADN and methyl 5-cyanopentanoate (MCP), when the reaction was performed in a fixed-bed reactor with a filling of 6 mL of catalyst at a liquid hourly space velocity of DMA (LHSV DMA ) of ∼0.5 h −1 . We envisioned that the oxygen-deficient oxides (WO x<3 ) may improve the electrical conductivity and donor density and thus enhance the surface species (such as NH 3 and DMA) adsorption, signifying great potential in NH 3 activation and subsequent nitrilation.…”