Formamide Dehydration Research Articles

Catalytic synergy between MoO 3 and BiPO 4 in N-ethyl formamide dehydration : II. Characterization of mixtures of MoO 3 and BiPO 4

This paper concerns the physicochemical characterization of mixtures of BiPO 4 and MoO 3 powders whose catalytic activity in the dehydration of N-ethyl formamide has been reported previously. The aim of the work was to investigate whether the existence of any mixed BiPMo oxide species, due to a contamination of the surface of one phase by elements coming from the other phase, could explain the synergy. Analytical Electron Microscopy (AEM) detects a contamination of BiPO 4 by MoO 3 only when the mixture is prepared from suspensions of BiPO 4 and MoO 3 in water. Electron Spectroscopy for Chemical Analysis-X-Ray Photoelectron Spectroscopy (ESCA-XPS) results cannot give any valuable information with respect to contamination, due to the relatively important thickness of the surface layer analyzed. Ion Scattering Spectroscopy shows a contamination in the same case as AEM. The MoO 3-contaminated layer is easily removed by ion sputtering. We conclude that, except for the fresh mixture prepared with water, no surface contamination of one phase by elements of the other phase can be detected in fresh catalysts or in catalysts having worked in the reacting mixture of N-ethyl formamide and oxygen at moderate temperatures.

Catalytic synergy between MoO 3 and BiPO 4 in N-ethyl formamide dehydration : III. An ESR study of reduction properties of the mixtures of MoO 3 and BiPO 4

A study of the interactions between MoO 3 and BiPO 4 in mixed oxide catalysts active in N-ethyl formamide dehydration was made by determining the Mo(V) Electron Spin Resonance (ESR) signal intensities after reduction, under different conditions, of mechanical mixtures of separately prepared BiPO 4 and MoO 3. The signal intensity clearly depended on the intimacy of contact, the reducibility of MoO 3 in mechanical mixtures being higher than in pure MoO 3. The mixing method in which both powders were dispersed together in n-pentane was the most effective. Alternate reducing and oxidizing treatments showed that the reaction was reversible at high temperature. After comparison of the ESR results with catalytic activities, it is concluded that, during catalysis, reoxidation by oxygen of the MoO 3 surface is necessary to counterbalance the reducing effect of formamide, thus restoring the catalytically active sites.

Formamide as a precursor to cyanide in mixed-valence copper(I,II) cyanide complexes

Copper(I) acetate reacts with acetic anhydride–formamide (1 : 1) in acetonitrile solution to give [Cu2(O2CMe)(CN)] or [Cu2(CN)2(NCMe)]. Anhydrous copper(II) acetate reacts with the same reagent to give [Cu(NCMe)4][Cu2(CN)4] and [Cu(O2CMe)2(HCONH2)]. The influence of various polar solvents on the products of the reaction is evaluated. The complex [Cu(NCMe)4)][Cu2(CN)4] reacts with unidentate nitrogen-donor ligands, L, to form [CuL4][Cu2(CN)4](L = pyridine or 4-methylpyridine) or [CuL3][Cu2(CN)4](L = 2-methylpyridine or 2,6-dimethylpyridine). With bidentate nitrogen-donor ligands, L–L, substitution in [Cu(NCMe)4][Cu2(CN)4] gives [Cu(L–L)2(NCMe)][Cu2(CN)4](L–L = 1,2-diaminoethane or 2,2′-bipyridine). The insoluble complex products are obtained in good yield and characterized by microanalysis and spectroscopy (i.r. and visible reflectance). The role of copper ions in promoting the dehydration of formamide by acetic anhydride is assessed.

Catalytic Synergy in the Catalysis of N‐Ethyl Formamide Dehydration by Metal Oxides in Separate Phases

AbstractMixtures of separately prepared oxides (of Mo, V, W, Bi, Sb, Sn) and BiPO4 exhibit a marked synergy in catalysis of the dehydration of N‐ethyl formamide in the presence of molecular oxygen, supporting the idea that a remote control of the active centres on one of the phases is exerted by the other phase via a special oxygen species.

Syntheses with stable isotopes: Sodium cyanide‐13C

AbstractSodium cyanide‐ 13C has been prepared in 65–70% overall yield from carbon‐13C monoxide in a three‐step synthesis proceeding through isopropyl formate‐ 13C and formamide‐ 13C as intermediates. Several. methods for the dehydration of formamide have been investigated.

MICROCHEMICAL DETECTION OF ELECTROPHILIC CHEMICALS

Abstract N-Alkylformamides are shown to be useful in the detection of electrophiles by the formation of isocyanides. Down to 0.2 μ of tosyl chloride is detectable by combining the formamide dehydration with a colorimetric estimation of isocyanide.