Molecular beam mass spectrometry has been used for an in situ study of the Pt-catalyzed formation of hydrocyanic acid from methane and ammonia. The goal was to identify transient gas phase intermediates which would indicate homogeneous contributions to the reaction mechanism. A catalytic wall reactor operated at 1300 1C, 1013 mbar, and 74% HCN yield was connected via a molecular beam interface with a quadrupole mass spectrometer, which allowed the measurement of ionization-and appearance potentials by electron impact. Shape and width of the electron energy spread function were determined by analyzing the ionization efficiency curve of helium; the experimental uncertainty of the measured threshold values was found to be 0.6 eV. By use of the threshold ionization technique it could be shown that methylamine (CH 3 NH 2 ) and methylenimine (CH 2Q NH) are present in the gas phase under reaction conditions. The measured threshold potentials at m/z ¼ 30 u (9.9 AE 0.6 eV) and m/z ¼ 29 u (10.6 AE 0.6 eV) were unambiguously assigned to the appearance potential of CNH 4 1 /CH 3 NH 2 and the ionization potential of CNH 3 1 /CH 2 NH, respectively. Both molecules dehydrogenate rapidly at reaction temperature to HCN so that they can be considered as true gas phase intermediates.

For converting methane and ammonia to hydrocyanic acid, catalysts were prepared and tested in a 48-parallel channel fixed-bed reactor unit operating at temperatures up to 1373 K. The catalysts were synthesized with a robot applying a genetic algorithm as the design tool. New and improved catalyst compositions were discovered by using a total of seven generations each consisting of 92 potential catalysts. Thereby, the catalyst support turned out as an important input variable. Furthermore, platinum, which is well known as a catalytic material was confirmed. Moreover, improvements in HCN yield were achieved by addition of promoters like Ir, Au, Ni, Mo, Zn and Re. Multi-way analysis of variance and regression trees were applied to establish correlations between HCN yield and catalyst composition (support and metal additives). The obtained results are considered as the base for future even more efficient screening experiments. #

The sections in this article are Introduction The A ndrussow Process History Fundamentals Production of Liquid Hydrocyanic Acid Pressure Variant Oxygen Variant Ammonia Recycling Reactor and Catalyst The BMA Process Overview Development of the Catalyst Development of the BMA Tubes Reactor Design Mechanism and Kinetics of HCN formation in the BMA and A ndrussow Processes Kinetics and Mechanism of the BMA Process Thermodynamic Context HCN and N 2 Formation Coke Formation On the Role of Gas‐Phase Reactions Catalytically Active Centers Kinetics and Mechanism of the A ndrussow Process Thermodynamic Relationships HCN Formation HCN Hydrolysis Catalytically Active Centers Final Remarks

The carbenoids 2 undergo at -110°C a bromine/lithium exchange reaction with 1,l-dibromo alkanes. This leads to partial equilibration of the carbenoids 2 during their generation from the 1,l-dibromo compound 1. In the absence of the precursor 1, the carbenoids 2 have been found to be configurationally stable at -110°C.Diastereoselectivity in the formation of the products 3 from the dibromo compound 1 via the diastereomeric carbenoids 2*) depends on the relative magnitude of the various rate constants for (a) the kinetic diastereoselectivity in the exchange of the diastereotopic bromine atoms in 1 ( = kl), (b) the epimerisation of the carbenoids 2 (= k2) and (c) the trapping of the carbenoids 2 by electrophiles (= k3). We report here on investigations to gain a better understanding of the mechanistic aspects of this reaction. Me3Si0Br c --

Bromine-lithium exchange in l,l-dibromo-3-(trimethylsilyl-silylating agents. Diastereoselectivity in the generation and oxy)alkanes 4 and 6 affords the carbenoids 8 and 14, which trapping of the carbenoids ranged between 70 -90% for 8 and have been added to ketones, aldehydes, arylboronates, and >90% for 14.