Removal of phosgene impurity from boron trichloride by laser radiation

A method for dissociation of COCl.sub.2 by laser irradiation of COCl.sub.2 in presence of a gaseous compound selected from BCl.sub.3 and C.sub.2 H.sub.4, said selected gaseous compound when BCl.sub.3 having a fundamental whose energy is close to that of one of the COCl.sub.2 fundamentals and said selected gaseous compound when C.sub.2 H.sub.4 having combination bands and overtones that match reasonably close to the energy of COCl.sub.2 so that a transfer of energy takes place between said selected gaseous compounds and said COCl.sub.2 when irradiated by laser radiation to effect dissociation of said COCl.sub.2 when irradiated by laser radiation to effect dissociation of said COCl.sub.2, said method comprising:

• i. metering said selected gaseous compound and said COCl.sub.2 in admixture into a laser cell to achieve a predetermined pressure of said selected gaseous compound and said COCl.sub.2 which comprise the gaseous components in said laser cell, said predetermined pressure to ensure consonance between the concentration of said gaseous components and the power level of a cw CO.sub.2 multiline laser employed to irradiate said gaseous compound and said COCl.sub.2 to effect dissociation of said COCl.sub.2 ;
• ii. irradiating said selected gaseous compound and said COCl.sub.2 in admixture by a cw CO.sub.2 multiline laser at a predetermined power level of said cw CO.sub.2 multiline laser for a predetermined time period to effect dissociation of said COCl.sub.2 ;
• and,
• iii. obtaining a spectra of the static products of said admixture to detect said dissociation products of said COCl.sub.2 and to determine when all the COCl.sub.2 has been dissociated into dissociation products which are substantially CO and Cl.sub.2 and said spectra to additionally detect any appreciable depletion of said selected gaseous compound.