Acetylene catalytic hydrochlorination over powder catalyst prepared by pre-milling of K2PtCl4 salt

Митченко, С. А.; Krasnyakova, T. V.; Mitchenko, R. S.; Korduban, A. M.

doi:10.1016/j.molcata.2007.05.036

Cited by 89 publications

(40 citation statements)

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“…Mechanical activation of K 2 PdCl 4 in an atmosphere of the indicated unsaturated hydrocarbons, similar to mechanical activation of K 2 PtCl 4 [9], leads to the formation of complexes with coordination vacancies, acting as active sites for the heterogeneous catalyst. By analogy with hydrochlorination on mechanically-activated K 2 PtCl 4 (platinum system) [9], the stepwise mechanism for the hydrochlorination of acetylene by gaseous HCl on previously treated K 2 PdCl 4 (palladium system) may be presented as follows.…”

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confidence: 95%

“…By analogy with hydrochlorination on mechanically-activated K 2 PtCl 4 (platinum system) [9], the stepwise mechanism for the hydrochlorination of acetylene by gaseous HCl on previously treated K 2 PdCl 4 (palladium system) may be presented as follows. Two adjacent surface palladium complexes take part in the reaction, one of which has a coordination vacancy PdCl 3 − .…”

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confidence: 99%

“…The chloroplatination of acetylene proceeding with the participation of a hydrogen chloride molecule is rate-limiting for the catalytic reaction in the previously studied platinum system. This is seen in the significant kinetic isotope effect upon replacing HCl with DCl (KIE = 4) [9]. Using the analogy between the platinum and palladium systems, we should also expect a significant isotope effect for the palladium system.…”

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Catalytic hydrochlorination of acetylene on mechanochemically-activated K2PdCl4

2008

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We report the catalysis of the hydrochlorination of acetylene on the surface of dry K 2 PdCl 4 subjected to prior mechanical activation in an atmosphere of acetylene or propylene. The stereochemistry of the reaction corresponds to trans addition of the halogen and hydrogen atoms to the C-C triple bond. The hydrogen halide is the source of the halogen atom in the reaction product. The mechanical activation of K 2 PdCl 4 , in contrast to the case of K 2 PtCl 4 , is also capable of activating the C-C double bond: propylene is hydrochlorinated under similar conditions to isopropyl chloride.Petroleum and natural gas are the major raw material sources for basic organic synthesis. Starting in the middle of the twentieth century, the use of these sources led to a change in the technology of the large-scale manufacture of many chemical products with reorientation to the use of olefinic raw materials and synthesis gas. Nevertheless, some processes for the large-scale manufacture of products such as vinyl ethers, pyrrolidone, N-methylpyrrolidone, and butanediol and the smaller-scale production of drugs, fragrances, and plant protection chemicals using acetylene have certain advantages and continue to be employed. Furthermore, acetylenic hydrocarbons are inevitably formed in the preparation of olefins from petroleum and natural gas. The use of these acetylenic hydrocarbons is dictated by the current scale of production and the cost of raw materials. On the other hand, in contrast to the case of petroleum, the reserves of coal and natural gas permit us to regard these materials as virtually inexhaustible sources of acetylene. In particular, the increasing interest in the chemistry of acetylene is clearly a function of these considerations (see the reviews of Beletskaya [1, 2]).One of the industrial methods for the manufacture of vinyl chloride involves the hydrochlorination of acetylene catalyzed by HgCl 2 on activated charcoal [3]. The high toxicity of this mercury catalyst and its relative instability [4] have led to a search for other catalytic systems. The hydrochlorination of acetylene under homogeneous conditions is catalyzed by various metal salts containing Cu I , Au III , Pd II , and Pt II [3]. The Pt II and Pd II complexes in solution have high activity but are very unstable. Under heterogeneous conditions, Au III [5, 6] and Rh III complexes [7] on activated charcoal catalyze the hydrochlorination of acetylene but these reactions require elevated temperature (170-180°C). Recently, we have discovered the catalysis of acetylene hydrochlorination on the surface of mechanically-activated K 2 PtCl 6 [8] and K 2 PtCl 4 [9]. We might 316 0040-5760/08/4405-0316

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Catalytic hydrochlorination of acetylene on mechanochemically-activated K2PdCl4

2008

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“…We note that propylene and acetylene, whose molecules are capable of occupying vacant coordination sites, were used as gases in systems with K 2 PtCl 4 in our previous work [7]. In the case of acetylene, the formation of p-acetylene complexes was confirmed by diffuse scattering IR spectroscopy as a band at 2095 cm -1 , corresponding to stretching vibrations of the C-C triple bond.…”

Section: Resultsmentioning

confidence: 92%

Effect of mechanicochemical treatment on the activity of K2PdCl4 in the heterogeneous catalytic hydrochlorination of acetylene

2010

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A heterogeneous catalyst for the hydrochlorination of acetylene using gaseous HCl was obtained by prior mechanical activation of K 2 PdCl 4 powder in an atmosphere of acetylene or propylene. Active sites are formed during the mechanical treatment in the surface layers of the catalyst, which are Pd(II) complexes with a coordination vacancy.One area in the development of green chemistry, which has recently become the predominant trend in the advancement of science [1, 2], is the chemistry of mechanically activated reactions involving solids. Examples of such processes include stoichiometric [2, 3] and catalytic reactions [4,5]. In the latter case, a heterogeneous catalyst undergoes mechanical treatment. Catalytically activated states are generated on the surface of solid-state catalysts as a result of mechanical activation. Some of these states are retained on the relaxed surface, which permits us to carry out catalytic transformations on a catalyst subjected to prior mechanical activation without the continual input of mechanical energy, thereby significantly simplifying the process [6].In previous work [7], we discovered the catalysis of the hydrochlorination of acetylene using gaseous HCl on the surface of K 2 PtCl 4 subjected to prior mechanical activation in an atmosphere of acetylene, ethylene, or propylene. The role of the active states is carried out by complexes with a coordination vacancy generated by prior mechanical activation of the catalyst:Such species are capable of coordinating acetylene virtually at the rate of diffusion to give p-complexes, which are key intermediates in the catalytic transformations of acetylene. In the mechanical activation of the platinum salt in an atmosphere of the gases mentioned above, equilibrium (1) is shifted to the right due to stabilization of the coordination-unsaturated species by means of p-coordination of the unsaturated hydrocarbons to them. 32

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“…Pt 3+ and Pd 2+ complexes in solution show high activity but they are very unstable [7]. For solid catalysts, gold-based catalyst has been considered as a promising catalyst to replace the mercury-based catalysts among various metal salts i.e., Au 3+ [5,8,9], Cu 2+ [10], Pd 2+ [11], Pt 2+ [12,13] and Bi 3+ [14]. However, their performance is not satisfactory for commercial production due to stability problems.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Au/C Catalysts by Ultrasonic-Assisted Technique for Vinyl Chloride Monomer Production

Wittanadecha

Laosiripojana

Ketcong³

et al. 2014

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Abstract. In the present work, the ultrasonic-assisted technique is applied to synthesize Au/C catalysts for vinyl chloride monomer (VCM) production via acetylene hydrochlorination. The catalytic performance of the obtained catalysts is compared with that of the catalyst prepared by a conventional incipient wetness impregnation technique. It was found that all the prepared catalysts show high VCM selectivity (>99.5%). The use of the ultrasonic-assisted technique can significantly improve the catalytic activity and stability of the synthesized Au/C catalysts. An ultrasonic driven time of 6 hours is found to be a promising catalyst for commercial application regarding the catalyst stability. In addition, the effect of operating parameters is investigated. Suitable operating temperature and HCl/C2H2 feed ratio are 180 o C and 1.1, respectively.

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Acetylene catalytic hydrochlorination over powder catalyst prepared by pre-milling of K2PtCl4 salt

Cited by 89 publications

References 11 publications

Catalytic hydrochlorination of acetylene on mechanochemically-activated K2PdCl4

Catalytic hydrochlorination of acetylene on mechanochemically-activated K2PdCl4

Effect of mechanicochemical treatment on the activity of K2PdCl4 in the heterogeneous catalytic hydrochlorination of acetylene

Synthesis of Au/C Catalysts by Ultrasonic-Assisted Technique for Vinyl Chloride Monomer Production

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