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Phsicochemical Treatment of Hazardous Wastes - Chapter 5

Khái niệm về cấu trúc-Hoạt động phân tích định lượng (QSAR) Mối quan hệ toán học để định lượng các mối tương quan giữa phản ứng và mô tả phân tử bằng cách sử dụng hóa chất trực giác và kinh nghiệm. Khi một mối tương quan giữa cấu trúc và hoạt động được tìm thấy, bất kỳ số lượng các hợp chất, bao gồm cả những người không được nêu ra tổng hợp, có thể dễ dàng đánh giá bằng cách sử dụng một máy tính để xác định treatability của một hợp chất hữu cơ nhất định. Treatability. | 5 Quantitative Structure-Activity Relationships 5.1 Introduction The concept of Quantitative Structure-Activity Relationship QSAR analysis is to mathematically quantify the correlations between reactivity and molecular descriptors using chemical intuition and experience. Once a correlation between structure and activity is found any number of compounds including those not yet synthesized can be readily assessed using a computer to determine the treatability of a given organic compound. Treatability of organic pollutants by a specific Advanced Oxidation Process AOP is usually carried out through laboratory studies however the combination of dozens of AOPs and thousands of toxic organic pollutants makes it impossible to evaluate the treatability of each pollutant by each AOP. In addition experimental studies are usually very costly and time consuming. Fortunately a class of organic pollutants reacts similarly to a given AOP because similar changes in structure produce similar changes in reactivity according to the QSAR theory therefore QSAR analysis can be used as an important tool to assess the treatability of a variety of organic pollutants by an AOP. 5.2 Fundamental Theory of QSAR Quantitative structure-activity relationship studies are of great importance in modern chemistry. From their origin in the study of organic chemistry dating back to the 19th century these studies have relied on some empirical and qualitative rules about the reactivity similarities of compounds with similar structures. The most significant development in QSARs occurred with the work of Louis Hammett 1894-1987 who correlated some electronic properties of organic acids and bases with their equilibrium constants and reactivity Johnson 1973 . Hammett postulated that the effect 2004 by CRC Press LLC of substituents on the ionization of benzoic acids could be used as a model system to estimate the electronic effect of substituents on similar reaction .