{"id":14058,"date":"2021-03-08T14:02:02","date_gmt":"2021-03-08T14:02:02","guid":{"rendered":"http:\/\/each.ut.ee\/EACH\/?p=14058"},"modified":"2024-08-03T16:43:13","modified_gmt":"2024-08-03T16:43:13","slug":"acidity-scale-in-acetonitrile-231-pka-values-spanning-30-orders-of-magnitude","status":"publish","type":"post","link":"https:\/\/each.ut.ee\/EACH\/acidity-scale-in-acetonitrile-231-pka-values-spanning-30-orders-of-magnitude\/","title":{"rendered":"Acidity scale in acetonitrile: 231 pKa values spanning 30 orders of magnitude"},"content":{"rendered":"\n<div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\">\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-28f84493 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:100%\">\n<div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\">\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-28f84493 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:100%\">\n<div class=\"wp-block-image\"><figure class=\"alignleft size-large is-resized\"><a href=\"https:\/\/analytical.chem.ut.ee\/wp-content\/uploads\/2021\/09\/Strengths-of-Acids-in-Acetonitrile-09-2021.pdf\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/each.ut.ee\/EACH\/wp-content\/uploads\/2021\/03\/Acid-pKa-08032021.png\" alt=\"\" class=\"wp-image-14063\" width=\"307\" height=\"273\"\/><\/a><\/figure><\/div>\n\n\n\n<p>The equilibrium acidity scale (p<em>K<\/em><sub>a<\/sub> scale) in acetonitrile (MeCN) has been supplemented by numerous new compounds and new \u0394p<em>K<\/em><sub>a<\/sub> measurements and has been published in <a href=\"https:\/\/doi.org\/10.1002\/ejoc.202001649\"><em>Eur. J. Org. Chem<\/em>. <strong>2021<\/strong>, 1407\u20131419 (Open access)<\/a>. The p<em>K<\/em><sub>a<\/sub> scale&nbsp;now contains altogether 231 acids \u2013 over twice more than published previously \u2013 linked by 566 \u0394p<em>K<\/em><sub>a<\/sub> measurements and spans between the p<em>K<\/em><sub>a<\/sub> values of hydrogen iodide (2.8) and indole (32.57), covering close to 30 orders of magnitude. The acids have wide structural variety, ranging from common families &#8211; phenols (e.g. picric acid, alizarin, polyhalogenophenols), carboxylic acids (e.g. acetic, benzoic, retinoic and sorbic acid), sulfonic acids, hydrogen halides) to highly special molecules (chiral BINOL catalysts, bis(benzoxazole-2-yl)methanes, polyfluorinated&nbsp;compounds) and superacids (fluorinated sulfonimides, cyanoform, tetracyanopropenes).<\/p>\n\n\n\n<p>Measurement results acquired over the last 15 years were added to the scale and new least squares treatment was carried out. The treatment yielded revised p<em>K<\/em><sub>a<\/sub> values for the compounds published previously, with the root mean square difference between revised and previous values 0.04, demonstrating very good stability of the scale.<\/p>\n\n\n\n<p>Correlation equations were developed for estimating p<em>K<\/em><sub>a<\/sub> values for the studied types of compounds in water, DMSO, DMF and 1,2-dichloroethane on the basis of p<em>K<\/em><sub>a<\/sub> values in acetonitrile. These equations enable predicting p<em>K<\/em><sub>a<\/sub> values with an average error around or less than 1 p<em>K<\/em><sub>a<\/sub> unit, which is a sufficient accuracy for many applications.<\/p>\n\n\n\n<p>The scale is expected to be a useful tool for the widest possible research areas in organic chemistry, electrochemical power sources, catalysis, etc.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>The equilibrium acidity scale (pKa scale) in acetonitrile (MeCN) has been supplemented by numerous new compounds and new \u0394pKa measurements and has been published in Eur. J. Org. Chem. 2021, 1407\u20131419 (Open access). The pKa scale&nbsp;now contains altogether 231 acids \u2013 over twice more than published previously \u2013 linked by 566 \u0394pKa measurements and spans [&hellip;]<\/p>\n","protected":false},"author":23,"featured_media":14063,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-14058","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/each.ut.ee\/EACH\/wp-json\/wp\/v2\/posts\/14058","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/each.ut.ee\/EACH\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/each.ut.ee\/EACH\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/each.ut.ee\/EACH\/wp-json\/wp\/v2\/users\/23"}],"replies":[{"embeddable":true,"href":"https:\/\/each.ut.ee\/EACH\/wp-json\/wp\/v2\/comments?post=14058"}],"version-history":[{"count":5,"href":"https:\/\/each.ut.ee\/EACH\/wp-json\/wp\/v2\/posts\/14058\/revisions"}],"predecessor-version":[{"id":14566,"href":"https:\/\/each.ut.ee\/EACH\/wp-json\/wp\/v2\/posts\/14058\/revisions\/14566"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/each.ut.ee\/EACH\/wp-json\/wp\/v2\/media\/14063"}],"wp:attachment":[{"href":"https:\/\/each.ut.ee\/EACH\/wp-json\/wp\/v2\/media?parent=14058"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/each.ut.ee\/EACH\/wp-json\/wp\/v2\/categories?post=14058"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/each.ut.ee\/EACH\/wp-json\/wp\/v2\/tags?post=14058"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}