Methods and systems are provided for converting methane in a feed stream to acetylene. The method includes processing the acetylene to form a hydrocarbon stream having vinyl chloride. The hydrocarbon stream is introduced into a supersonic reactor and pyrolyzed to convert at least a portion of the methane to acetylene. The reactor effluent stream is be treated to convert acetylene to other hydrocarbon processes. The method according to certain aspects includes controlling the level of carbon monoxide in the hydrocarbon stream to limit downstream side reactions in the downstream processing units.