{"title":"Uncovering Factors That Affect the Efficiency of Azo Dye Synthesis in Organic Chemistry Laboratory","authors":"Kriangsak Faikhruea, Worakan Chutakool, Suwadee Jiajaroen, Kittipong Chainok, Tirayut Vilaivan, Thanit Praneenararat","doi":"10.1021/acs.jchemed.4c00133","DOIUrl":null,"url":null,"abstract":"The synthesis of azo dyes is an intriguing experiment that can attract students’ attention due to the vivid color of the obtained product. Nevertheless, some students did not obtain the desired product without obvious reasons. In this work, we conducted a series of experiments to probe the effects of various factors that may contribute to the success of the reaction using Sudan I as a model. In contrast to the expectation based on the limited thermal stability of diazonium salts, it was found that low temperature (i.e., <10 °C) is not a critical factor for the success of the reaction. In fact, no statistically significant decrease in yield was found even when the reaction was performed at 20–30 °C. Instead, the key to success lies in the rate of reagent addition, where the coupling step must be performed slowly. Also, the cause of different color hues of the product was investigated. Both the presence of impurities (which were clearly identified in this study) and crystal polymorphisms contribute to the different colors among products from different batches that appeared to be the same Sudan I. Overall, these findings provide important information in designing azo dye synthesis experiments, which have diverse variations and modifications.","PeriodicalId":43,"journal":{"name":"Journal of Chemical Education","volume":null,"pages":null},"PeriodicalIF":2.5000,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Chemical Education","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/acs.jchemed.4c00133","RegionNum":3,"RegionCategory":"教育学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
The synthesis of azo dyes is an intriguing experiment that can attract students’ attention due to the vivid color of the obtained product. Nevertheless, some students did not obtain the desired product without obvious reasons. In this work, we conducted a series of experiments to probe the effects of various factors that may contribute to the success of the reaction using Sudan I as a model. In contrast to the expectation based on the limited thermal stability of diazonium salts, it was found that low temperature (i.e., <10 °C) is not a critical factor for the success of the reaction. In fact, no statistically significant decrease in yield was found even when the reaction was performed at 20–30 °C. Instead, the key to success lies in the rate of reagent addition, where the coupling step must be performed slowly. Also, the cause of different color hues of the product was investigated. Both the presence of impurities (which were clearly identified in this study) and crystal polymorphisms contribute to the different colors among products from different batches that appeared to be the same Sudan I. Overall, these findings provide important information in designing azo dye synthesis experiments, which have diverse variations and modifications.
期刊介绍:
The Journal of Chemical Education is the official journal of the Division of Chemical Education of the American Chemical Society, co-published with the American Chemical Society Publications Division. Launched in 1924, the Journal of Chemical Education is the world’s premier chemical education journal. The Journal publishes peer-reviewed articles and related information as a resource to those in the field of chemical education and to those institutions that serve them. JCE typically addresses chemical content, activities, laboratory experiments, instructional methods, and pedagogies. The Journal serves as a means of communication among people across the world who are interested in the teaching and learning of chemistry. This includes instructors of chemistry from middle school through graduate school, professional staff who support these teaching activities, as well as some scientists in commerce, industry, and government.