The Direct Synthesis, or Rochow Synthesis, involves the reaction of methyl chloride, CH3Cl (MeCl), with Cu-Si contact masses (promoted with 1-2% of Zn, Sn, and P) to form methylchlorosilanes. Flow reactor studies (1 bar MeCl at 300 A degrees C) showed that contact masses promoted with Zn, Sn, and P (triply promoted) demonstrated the highest Si and MeCl conversion at early reaction times. In situ infrared spectroscopy suggested that in contrast to the doubly promoted catalysts (where CH3 groups were primarily bound to Si), surface CH3 showed appreciable binding to the copper component of the triply promoted contact mass. This change in surface composition ultimately led to a drop in reactivity and selectivity of the triply promoted catalyst.