Comparative Study on the Acid-Base Indicator Properties of Natural Dye, Turmeric Rhizome (Curcuma longa) and Synthetic Dyes  

作　　者：Genevive Chinyere Onuegbu Onyekachi Onyinyechi Nnorom Gerald Okwuchi Onyedika Genevive Chinyere Onuegbu;Onyekachi Onyinyechi Nnorom;Gerald Okwuchi Onyedika(Department of Polymer and Textile Engineering, Federal University of Technology, Owerri, Nigeria;Department of Chemistry, Federal University of Technology, Owerri, Nigeria)

机构地区：[1]Department of Polymer and Textile Engineering, Federal University of Technology, Owerri, Nigeria [2]Department of Chemistry, Federal University of Technology, Owerri, Nigeria

出　　处：《Journal of Textile Science and Technology》2023年第1期20-29,共10页纺织科学与技术（英文）

摘　　要：Acid-Base Indicator, Turmeric Rhizome (Curcuma longa) was extracted from the root of a turmeric plant. The turmeric was peeled, washed and dried in an oven at 60°C. It was ground into powder and soaked in hot and cold ethanol for the extraction. The extract was filtered and part of it was concentrated to yield a reasonable quantity of turmeric indicator. On standardization of acid with a base, 0.05 M base respectively of Sodium hydroxide (NaOH), sodium carbonate (Na₂CO₃) and Disodium borate (B₄Na₂O₇) were used. Hot and cold extracts of turmeric were used as indicators and were compared with methyl orange and phenolphthalein. On the preliminary test carried out, hot and cold turmeric indicator showed yellow colour in acid medium and orange colour in the base. Methyl orange showed red colour in acid but yellow in the base, phenolphthalein was colourless in acid but pink in the base. During titration there were colour changes at the end points in the entire test carried out. The average volumes at ends points were calculated, the molar concentrations and mass concentrations of the acids used were also determined. The results showed that there was no difference between the natural indicators used and the existing synthetic indicators which are toxic to our environment.Acid-Base Indicator, Turmeric Rhizome (Curcuma longa) was extracted from the root of a turmeric plant. The turmeric was peeled, washed and dried in an oven at 60°C. It was ground into powder and soaked in hot and cold ethanol for the extraction. The extract was filtered and part of it was concentrated to yield a reasonable quantity of turmeric indicator. On standardization of acid with a base, 0.05 M base respectively of Sodium hydroxide (NaOH), sodium carbonate (Na₂CO₃) and Disodium borate (B₄Na₂O₇) were used. Hot and cold extracts of turmeric were used as indicators and were compared with methyl orange and phenolphthalein. On the preliminary test carried out, hot and cold turmeric indicator showed yellow colour in acid medium and orange colour in the base. Methyl orange showed red colour in acid but yellow in the base, phenolphthalein was colourless in acid but pink in the base. During titration there were colour changes at the end points in the entire test carried out. The average volumes at ends points were calculated, the molar concentrations and mass concentrations of the acids used were also determined. The results showed that there was no difference between the natural indicators used and the existing synthetic indicators which are toxic to our environment.

关 键 词：Turmeric Rhizome EXTRACTION Acid-Base Indicator Methyl Orange PHENOLPHTHALEIN 

分 类 号：O62[理学—有机化学]