Multiple chemical reactions are performed in a plurality of reaction vessels mounted in inlets in a manifold valve block. The manifold valve block is connected to a channel block which is utilized in conjunction with a solvent delivery system as part of the reaction cycle. The solvent fluid is drained from the reaction vessels when valves in the manifold valve block are opened while applying a vacuum thereto. Optionally, a thermal block may be utilized in conjunction with the manifold valve block and the channel block to facilitate the reaction. Upon completion of the reactant cycle, the manifold valve block is disconnected from the channel block and connected to a cleavage block assembly which contains vials for collecting reaction products. The cleavage product is drained from the reaction vessels through the manifold valve block into the vials upon opening the valves in the manifold valve block and applying a vacuum to the channel block.