Analysis of nitrile synthesis gas streams

Gas streams flowing in a nitrile synthesis plant, and particularly the hot reactor effluent gases, are analyzed by a new method wherein sample gas streams are filtered and temperature conditioned in the range from about 350 DEG to about 450 DEG F. before being passed to a gas analyzer instrument, preferably a mass spectrometer. With the latter instrument the conditioned stream of gas is passed continuously through the ion source assembly throughout the mass scan period, a mode of operation which assists in reducing lag in analysis to very little more than gas transit times. The mass spectrometer generates peaked direct current electrical signals which can be peak detected and amplified in a linear fashion to drive a direct-reading recorder instrument or such signals can be interfaced with a digital computer for programmed computation and readout of gas stream composition. The rapidity, reliability and accuracy of the analysis provides accurately calibrated control of the nitrile synthesis wherein a 1-monoolefin such as propylene or isobutylene are blended with ammonia and oxygen or air and passed through a bed of solid ammoxidation catalyst. Operation of such process in response to such analysis permits hitherto impractically low molar feed ratios of ammonia:olefin of 1.03 to 1.07:1 and high excess effluent oxygen levels of 4 to 7 mol % in the reactor effluent gases without significant losses in nitrile yield or significantly increased levels of oxygenated by-products.