Tyrosine was converted to p-hydroxystyrene in a two-step reaction without purification of individual intermediates. The apparatus and associated method cleans and pressure tests a tube by engaging a tube between the feed header interface and the drain header interface and maintaining said engagement while sequentially flowing a cleaning fluid through the inner diameter of the hollow tube, pressurizing a static fluid within the hollow tube, and releasing fluid from the tube. A pair of closure doors is articulately mounted on the platform for swinging movement between co-planar, closed positions, closing the opening and transverse, open positions.