Mixing Machine of High Precision for Study of Rapid Reactions

Abstract

The mixing machine described was designed for use in the study of certain rapid reactions by the steady-state-of-flow method. This machine combines several features not previously described for a single machine. (1) It may be used for reactions whose range of half-reaction times varies from 6 milliseconds to 1.6 seconds. This wide range is obtained by varying syringe piston speed to change the velocity of flow and by inserting spacer units to increase the length of reaction path. (2) It give results of high precision when used with the ``chemical stop'' method. The combination of precision-machined syringes and sensitive sampling and timing mechanism gives data from which precise calculations of velocities of flow and reaction time can be made. (3) The combination of three separate mixing chambers with or without spacer units enables one to premix sensitive reagents, immediately before initiating the primary reaction. The performance of the machine was evaluated by measuring the rates of a first-order reaction using the steady-state-flow technique.