{"title":"Advances in Derivative Voltammetry - A Search for Diagnostic Criteria of Several Electrochemical Reaction Mechanisms","authors":"Myung-Hoon Kim","doi":"10.5772/INTECHOPEN.96409","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.96409","url":null,"abstract":"New methods for analysis of current-potential curves in terms of their derivatives are presented for studying various types of electrode processes – such as simple electron transfer reactions (reversible, quasi-reversible, and irreversible electron transfer) as well as chemically coupled electron transfer reactions along with a diagnostic scheme for differentiating these various types of electrochemical reaction mechanisms. Expressions for first- and higher order derivatives are derived from theoretical analytical solutions for currents for the different types of electrode mechanisms. The derivative curves are analyzed in terms of various parameters which characterize peak shape or peak symmetry with an emphasis on the second derivatives with well-defined anodic and cathodic peaks. Second derivatives can yield, in a simpler manner, the symmetry ratios; i.e., a ratio of anodic to cathodic peak-currents (ipa/ipc), and a ratio of anodic to cathodic peak-widths (Wpa/wpc) and a ratio of anodic to cathodic peak potential differences (ΔEpa/ΔEpc) or a peak separation (Epa-Epc) are evaluated, and these ratio can be related to kinetic parameters associated with a particular types of electrode mechanisms. Peaks are found to be symmetrical for a simple reversible electron transfer process (Er). However, peaks become asymmetrical when the electron transfer become slower (namely, irreversible, Eirr) or e− transfer reaction is coupled with homogeneous chemical reactions such as a prior reaction (CEr) or a follower-up reaction (ECr). From measured values of such symmetry ratios above, one can gain insight to the nature of the electrochemical systems enabling us to determine various kinetic parameters associated with a system. A diagnostic criteria for assigning an electrode mechanism is devised based on the values of asymmetry parameters measured, which are unity for a simple reversible electron transfer process.","PeriodicalId":308772,"journal":{"name":"Analytical Chemistry - Advancement, Perspectives and Applications","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128036009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Improving the Technology of Synthesis Absolutized Bioethanol","authors":"S. Kurta, Khatsevich Olga","doi":"10.5772/INTECHOPEN.92332","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.92332","url":null,"abstract":"The article describes the technology of synthesis of absolute ethyl alcohol, as well as the types, properties and efficiency of water-withdrawing reagents and types, properties and efficiency of reagents (CaO, tetraethoxytitanium), which chemically bind water and dehydrate ethanol. The composition and properties of the absolutized ethanol were studied using the infrared spectroscopy, mass spectroscopy and gas-chromatography. The octane number of gasoline with the addition of absolutized ethanol together with the combustion activator (diethyl ether) was measured as well. It has been shown that the content of even very small amounts (up to 2%) of the combustion activator in absolutized ethanol results in the increase of the octane number and improves running abilities of gasoline.","PeriodicalId":308772,"journal":{"name":"Analytical Chemistry - Advancement, Perspectives and Applications","volume":"10 18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133742872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}