strongly by increasing the percentage of the organic component. The conclusions drawn show that ( i ) it is possible to predict the rate of nitrosation of phenolics as a function of the meta -substituents on the phenol ring and ( ii ) the nitrosation of phenolics can be strongly inhibited by increasing the pH of the reaction medium as well as by lowering its dielectric constant.
苯酚的亚硝化反应中, 直径: 甲酚,2,6-二甲基苯酚, ö - 叔 丁基苯酚,2-羟基苯乙酮,并在水和水/乙腈2-烯丙基苯酚进行了研究。反应的动力学监测是通过在345 nm处对亚硝化产物进行分光光度分析来完成的。占主导地位的反应是C-亚硝化 , 其机理包括NO + / NO 2 H 2 +对亚硝化底物的攻击,然后进行缓慢的质子转移。供电子取代基增加了酚C-亚硝化反应的速率常数,并获得了良好的 哈米特 ρ= -6.1时观察到相关性。该结果还显示的强作用 pH值 和速率常数,其最大值之前观察到的反应介质的介电常数 的pH ≈3,对于较高的强烈降低 的pH 值。在水/乙腈含量高达25%的乙腈中进行的研究表明,可以通过增加有机组分的百分比来强烈抑制反应。得出的结论表明( i )可以预测酚类化合物的亚硝化速率与酚环上 间位 取代基的函数关系, 并且( ii )酚类化合物的亚硝化作用可通过增加苯甲酸酯的含量而受到强烈抑制。
A study of the reaction of different phenol substrates with nitric oxide and peroxynitrite
作者:Susana Yenes、Angel Messeguer
DOI:10.1016/s0040-4020(99)00877-7
日期:1999.12
investigated. In general, nitration is the major reaction with peroxynitrite, while reactions with aqueous solutions of nitric oxide led to mixtures of nitro and nitroso derivatives depending upon the phenol. Nitrosation occurs on phenol substrates bearing a free para- position with respect to the OH group with the exception of 1-naphthol, which afforded a 1:1 mixture of the 2- and the 4-nitroso derivatives
Mechanistic studies of fluorescent sensors for the detection of reactive oxygen species
作者:Belinda Heyne、Sara Ahmed、J. C. Scaiano
DOI:10.1039/b713575k
日期:——
Two new sensors for the detection of reactive oxygen species have been synthesized and characterized; they contain the 4-amino-7-nitrobenzofurazan (ABF) moiety covalently tethered to a phenol. Comparison of sensors ABFhd and dABFhd (the latter containing two ortho-methyl groups) shows that introduction of steric bulk leads to an improvement of fluorescent sensor performance, thus confirming our previous predictions based on computational chemistry. ABFhd and dABFhd are new tools for biological applications involving reactive oxygen species, in particular oxygen-centered radicals.
Photosensitive composition and pattern forming process using same
申请人:Hitachi, Ltd.
公开号:US04510226A1
公开(公告)日:1985-04-09
A photosensitive composition becoming sticky upon exposure to light which comprises (a) a salt of a diazonium compound represented by the formula ##STR1## wherein R.sub.1 and R.sub.2 are independently --H, --CH.sub.3, --OCH.sub.3 or ##STR2## but R.sub.1 and R.sub.2 cannot be ##STR3## at the same time; and R.sub.3 and R.sub.4 are independently a straight-chain lower alkyl group, and (b) a salt of an aromatic diazonium compound having no --OH group directly bonding to a benzene ring, has an improved sensitivity because it contains the salt of the compound represented by the above formula. By using said photosensitive composition, there is provided a process for forming a pattern of powder coated layer excellent in light sensitivity.