Nitrogen‐Doped Pitch‐Based Spherical Active Carbon as a Nonmetal Catalyst for Acetylene Hydrochlorination

Abstract

A highly active nitrogen‐doped pitch‐based spherical activated carbon catalyst (PSAC‐N) is synthesized through a nitrogen‐doping treatment and used as a nonmetal catalyst for acetylene hydrochlorination. The conversion of acetylene on PSAC‐N exceeds 68 % and the selectivity of vinyl chloride is over 99 % at a temperature of 250 °C, an acetylene gas hourly space velocity of 120 h−1, and a feed volume ratio V(HCl)/V(C2H2) of 1.15. DFT calculations performed with Gaussian 09 program package reveal that the active site of PSAC‐N has a N‐6v (quaternary nitrogen bonded between two 6‐membered rings) structure. A seven benzene ring unit model is used in the DFT study. In addition, the reason for inactivation for PSAC‐N catalysts is discussed. Of all the adsorption energies obtained, the adsorption capacity of hydrogen chloride on PSAC‐N is the highest, which indicates strong ability for acetylene hydrochlorination. The reaction mechanism is determined, and the reaction energy of N‐6v(7) calculated as 236.2 kJ mol−1.

Development of a Heterogeneous Non-Mercury Catalyst for Acetylene Hydrochlorination

“…Therefore, the development of fully metal-free catalysts is of great importance for the production of the monomer vinyl chloride. Recently, heteroatom doping of carbon materials became the "Big Thingof Concern" in materials science, further proving to be versatile functional materials with a wide range of heterogeneous catalysis, including oxygen reduction reactions [61], biomass conversion [62], as well as acetylene hydrochlorination [63][64][65][66][67][68]. In particular, the carbon nitride materials enriched with nitrogen content have garnered a great deal of attention over the last few years.…”

“…Many researchers have proved that the heteroatom doping changes not only the carbon surface chemistry such as basicity but also the electronic structure by donating a lone pair of electrons on the undoped carbon lattice. To date, a number of carbon nitride nanocomposites have been proposed in which nitrogen is impregnated into porous activated carbon [63,67], pitch-based spherical activated carbon [64], multiwalled carbon nanotubes [65], silicon carbide [66] or grapheme [68] by chemical vapor deposition, heat-treatment with nitrogen sources, or direct carbonization of N-containing precursors. Carbon nitrideanocomposites applied to acetylene hydrochlorination as metal-free catalysts 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 and their respective nitrogen contents are summarized in Table 3.…”

Alternative solvent to aqua regia to activate Au/AC catalysts for the hydrochlorination of acetylene

“…Among the numerous metal chlorides [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] and inorganic catalytic materials such as nitrogen-doped carbon [26][27][28], AC-supported g-C 3 N 4 [29], C-doped boron nitride fullerene [30], and 13X zeolite [31], AC-supported AuCl 3 catalysts are considered the most promising materials for acetylene hydrochlorination [32][33][34]. Compared with HgCl 2 for acetylene hydrochlorination, AC-supported AuCl 3 catalysts significantly improve the catalytic activity.…”

Hydrochlorination of acetylene using expanded multilayered vermiculite (EML-VMT)-supported catalysts

“…The 16 acetylene hydrochlorination reaction was the earliest process for 17 the industrial production of vinyl chloride [1,2]. Up to date, China 18 has been the world's largest PVC production country, which 19 produces 20,000,000 t of PVC annually, accounting for 41% of total 20 world production capacity.…”

“…Recently, EML-VMT has been 49 used as catalyst supports, such as in the modified-VMT-supported 50 Ni catalysts for CO 2 methanation to syngas (SG) [14], VMT-51 supported TiO 2 as efficient photocatalysts for water decontamina-52 tion [15] and methylene blue photocatalytic degradations [16]. Catalytic performance was measured in a fixed bed reactor 108 according to our previous paper [17,18]. At first, the reactor was 109 purged with nitrogen to remove water and air in the reacting 110 system.…”