Shi Run,Wang Zeping,Zhao Yunxuan,Waterhouse Geoffrey I. N.,Li Zhenhua,Zhang Bikun,Sun Zhimei,Xia Chuan,Wang Haotian,Zhang Tierui
The selective hydrogenation of acetylene to ethylene in ethylene-rich gas streams is an important process in the manufacture of polyethylene. Conventional thermal hydrogenation routes require temperatures above 100 °C and excess hydrogen to achieve a satisfactory C 2 H 2 conversion efficiency. Here, we report a room-temperature electrochemical acetylene reduction system based on a layered double hydroxide (LDH)-derived copper catalyst that offers an ethylene Faradaic efficiency of up to ~80% and inhibits alkane and hydrogen formation. The system affords an acetylene conversion of over 99.9% at a flow rate of 50 ml min −1 in a simulated gas feed, yielding high-purity ethylene with an ethylene/acetylene volume ratio exceeding 10 5 and negligible residual hydrogen (0.08 vol.%). These acetylene conversion metrics are superior to most other state-of-the-art strategies. The findings therefore conclusively demonstrate an electrochemical strategy as a viable alternative to current technologies for acetylene-to-ethylene conversions with potential advantages in energy and atom economies.
Olefin/paraffin separations are among the most energy-intensive processes in the petrochemical industry, with ethylene being the most widely consumed chemical feedstock. Adsorptive separation utilizing molecular sieving adsorbents can optimize energy efficiency, whereas the size-exclusive mechanism alone cannot achieve multiple olefin/paraffin sieving in a single adsorbent. Herein, an unprecedented sieving adsorbent, BFFOUR-Cu-dpds (BFFOUR = BF 4 - , dpds = 4,4’-bipyridinedisulfide), is reported for simultaneous sieving of C 2 -C 4 olefins from their corresponding paraffins. The interlayer spaces can be selectively opened through stronger guest-host interactions induced by unsaturated C = C bonds in olefins, as opposed to saturated paraffins. In equimolar six-component breakthrough experiments (C 2 H 4 /C 2 H 6 /C 3 H 6 /C 3 H 8 /n-C 4 H 8 /n-C 4 H 10 ), BFFOUR-Cu-dpds can simultaneously divide olefins from paraffins in the first column, while high-purity ethylene ( > 99.99%) can be directly obtained through the subsequent column using granular porous carbons. Moreover, gas-loaded single-crystal analysis, in-situ infrared spectroscopy measurements, and computational simulations demonstrate the accommodation patterns, interaction bonds, and energy pathways for olefin/paraffin separations.
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