Products of the ultraviolet photodissociation of trifluoroacetic acid and acrylic acid
作者:Michael C. Osborne、g Li、Ian W. M. Smith
DOI:10.1039/a809064e
日期:——
The photodissociation of trifluoroacetic and acrylic acids by the ultraviolet light from a flashlamp has been investigated by measuring the relative yields of some of the major products by time-resolved infrared absorption using tunable, narrow band diode lasers. Yields of CO2 were measured both in the absence and presence of added O2. The former experiments measure the CO2 produced directly by decarboxylation of the acid, channel (2) below, the latter the sum of the yields from channels (1) and (2) since HOCO is rapidly converted to CO2. The yields of CO from the decarbonylation channel (3) have also been measured. For trifluoroacetic acid, the relative yields are found to be [HOCO]:[CO2]:[CO]=(0.28±0.07):(0.61±0.09):(0.11±0.06) and, for acrylic acid, [HOCO]:[CO2]:[CO]=(0.32±0.08):(0.37±0.08):(0.31±0.09). The results are discussed in relation to the other, limited, measurements on the photodissociation of these acids and whether these three processes are likely to occur independently of one another.
通过使用可调谐窄带二极管激光器的时间分辨红外吸收来测量一些主要产物的相对产率,研究了闪光灯紫外光对三氟乙酸和丙烯酸的光解。在不存在和存在添加 O2 的情况下测量 CO2 产量。前一个实验测量了酸脱羧直接产生的 CO2,即下面的通道 (2),后者是通道 (1) 和 (2) 的产量之和,因为 HOCO 快速转化为 CO2。还测量了脱羰通道 (3) 的 CO 产量。对于三氟乙酸,相对产率为 [HOCO]:[CO2]:[CO]=(0.28±0.07):(0.61±0.09):(0.11±0.06),对于丙烯酸,[HOCO]: [CO2]:[CO]=(0.32±0.08):(0.37±0.08):(0.31±0.09)。讨论的结果与这些酸的光解离的其他有限测量以及这三个过程是否可能彼此独立发生有关。