Diphenylcarbodiimide, Method II

Abstract

Diphenylcarbodiimide, Method II intermediate: N‐sulfinylaniline reactant: 50 g. (0.41 mole) of benzaldoxime solvent: 150 ml. of petroleum ether intermediate: benzohydroxamoyl chloride intermediate: triethylamine hydrochloride product: diphenyl carbodiimide

From a humorous post to a detailed quantum-chemical study: isocyanate synthesis revisited

“…Thus, it is hypothesized that the PhNSO compound formerly obtained in 14–18% yield in benzene is a product of the parallel reaction (B) and not the unreacted reagent. 48 It should be noted that upon changing the solvent from benzene to diethyl ether, the reagents are not purified from the final reaction mixture. 47 These observations are consistent with the results of in silico investigations: barrier heights of the first reaction steps (determining the ratio of the final product) in the pathways (A) and (B) are predicted to differ by 1.5 and 2.2 kcal mol −1 for reactions in benzene and in THF, respectively.…”

“…The PhNSO-catalyzed conversion PhCNO -PhNCO is also a possible but less favorable reaction pathway, and it explains the found traces of PhNCO in the reaction mixture. 47,48 In the end, we also surveyed the effect of phenyl ring substituents on the reaction kinetics. It turns out that such a substitution slows down the reaction with respect to the unsubstituted PhCNO.…”

“…More detailed kinetic modeling of the parallel reactions (A) and (B) involving reagents PhCNO and PhNSO predicts reaction (A) to be the main pathway, which is in line with the previously obtained experimental data. 47,48 Furthermore, non-negligible amounts (7% at 298 K, 12% at 383 K) of the corresponding product are predicted to form via the pathway (B). Thus, it is hypothesized that the PhNSO compound formerly obtained in 14-18% yield in benzene is a product of the parallel reaction (B) and not the unreacted reagent.…”

“…Thus, it is hypothesized that the PhNSO compound formerly obtained in 14-18% yield in benzene is a product of the parallel reaction (B) and not the unreacted reagent. 48 It should be noted that upon Fig. 7 Summary of reaction pathways identified in the inorganic catalyst survey for the phenylnitrile oxide into isocyanate conversion.…”

Synthesis and Characterisation of Diaryl Furoxans

“…Chloride (4) A solution of p-nitro benzaldoxime (0.332 g, 0.002 mol) in dimethyl formarmide (5 cm 3 ) was transferred to a 100 cm 3 round-bottom flask equipped with a guard tube, and n-chlorosuccinimide (0.332 g, 0.0024 mol) was added to it in small portions with vigorous stirring. The stirring was continued overnight.…”