On the Nature of the Active Copper State and on Promoter Action in Rochow Contact Masses

Ehrich, Heike; Born, D.; and, J. R. Hahn; Lieske, H.

doi:10.1002/9783527619900.ch80

Cited by 1 publication

(2 citation statements)

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“…By measurement of the total copper and determination of the dissolved copper, the percentage of copper as Cu 3 Si can be determined as the difference. We analyzed the contact mass by XRD, and the only phases we observed were free Cu, Cu 5 Si, and Cu 3 Si. , Our eta-phase measurement is a bulk measurement, unlike the measurements made at the atomic scale reported by Falconer , and others …”

Section: Methodsmentioning

confidence: 95%

“…The mixture is known as contact mass after the heating process, and the following reaction is assumed to have occurred when the silicon/CuCl mixture was heated: As indicated in eq 2, the state of copper in the contact mass is assumed to be Cu 3 Si. Although several groups support the notion that the eta phase is the key catalytic species in MCS reactions, ,− other raise doubt about this theory. − …”

Section: Methodsmentioning

confidence: 99%

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The Use of a Fixed-Bed Reactor to Evaluate the Interactions of Catalysts and Promoters in the Methyl Chlorosilane Reaction and to Determine the Effect of Cu in the Form of the Eta Phase on This Reaction

Lewis

Ward

2001

Ind. Eng. Chem. Res.

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A fixed-bed reactor was employed to study the methylchlorosilane (MCS) reaction, also called the direct process. We used a copper−silicon contact mass as the main MCS catalyst. The copper−silicon contact mass was prepared by the reaction of CuCl with silicon. The effect of added zinc and phosphorus to the MCS reaction was explored, and we found that, at Cu/Zn ratios > 30, phosphorus addition resulted in an increase in selectivity for dimethyldichlorosilane (Di) at the expense of methyltrichlorosilane (Tri) and residue. Addition of tin to the MCS reaction resulted in an increased overall rate but with a decrease in Di and an increase in disilane formation. Addition of phosphorus and high tin levels resulted in a high rate but with a high selectivity for Di; phosphorus negated the selectivity penalty caused by the addition of tin alone. Phosphorus appeared to cause an increase in formation of the eta phase (Cu3Si), as determined by analysis of MCS beds formed under different conditions. Previously reported arguments show that copper diffusion is operative for Cu−Si renewal in MCS but that Cu diffusion is not the rate-limiting step in the reaction.

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