HEATS OF FORMATION OF FORMYL SYSTEM

Abstract

Using ab initio molecular orbital (MO) theory to calculate the heats of formation of formyl system. Results show that, the heats of formation of formic acid (HC=O(OH)); methyl formaldehyde (HC=O(CH3)) and formyl amide (HC=O(NH2)) at CCSD(T)/6-311++G(3df,2p) // MP2/6-31G(d,p) level, were similar to the experimental results with different amount from 0.1 to 2.8 kJ/mol. The heats of formation of the rest of compounds have been calculated from four different working reactions at CCSD(T) method in conjunction with 6-311++G(3df,2p) basis set, with a probable error of ± 5 kJ/mol. This method can also be used to calculate heats of formation for compounds of the same system or others for which these quantities are not experimentally available.