scholarly journals Comparative Analysis of the Properties of Acid-Base Indicator of Rose (Rosa setigera), Allamanda (Allamanda cathartica), and Hibiscus (Hibiscus rosa-sinensis) Flowers

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Stanley I. R. Okoduwa ◽  
Lovina O. Mbora ◽  
Matthew E. Adu ◽  
Ameh A. Adeyi
Keyword(s):  
Comparative Analysis ◽  
Solvent Extraction ◽  
Ph Value ◽  
Visible Region ◽  
Electromagnetic Spectrum ◽  
Acid Base ◽  
Soxhlet Extractor ◽  
Synthetic Indicators ◽  
Hibiscus Rosa Sinensis ◽  
Acid And Base

The need to develop effective alternative for synthetic indicators is the demand of present-day chemistry. The acid-base indicator properties of Rose (Rosa setigera), Allamanda (Allamanda cathartica), and Hibiscus (Hibiscus rosa-sinensis) flowers were examined. Colour pigments were extracted from the flowers via cold and solvent extraction using soxhlet extractor. The pH value of the extracts with wavelengths of absorption was determined using ultraviolet spectrophotometer. From the results obtained, all the extracts exhibited sharp contrast between their colours in acid and base. Their pH was found to be 5.5 for cold extract of Rose and 5.6 for solvent extraction, 5.24 for cold extract of a Hibiscus and 6.52 for solvent extraction, 5.35 for cold extract of Allamanda, and 5.45 for solvent extraction. The maximum wavelengths of absorption obtained for all the extract fall within the visible region of electromagnetic spectrum. These values are almost similar to that obtained from synthetic indicators. It is on these bases that we concluded that natural indicators could be an excellent replacement for synthetic indicators since they are cheap, readily available, simple to extract, not toxic, user and environmentally friendly.

scholarly journals The Potential of Clitoria ternatea L. Extracts as an Alternative Indicator in Acid-Base Titration

2021 ◽  
Vol 5 (4) ◽  
pp. 340-352
Author(s):  
Camalin Bela Sukmaning Fitri* ◽  
Retno Aliyatul Fikroh
Keyword(s):  
Experimental Design ◽  
Base Material ◽  
Chemistry Curriculum ◽  
Acid Base ◽  
Flower Extract ◽  
Synthetic Indicators ◽  
Base Materials ◽  
Acid Base Titration ◽  
Acid And Base ◽  
Butterfly Pea

Experiments are an important part of the chemistry curriculum. An indicator in the form of a synthesis indicator is commonly used in acid-base materials experiments. The usage of synthetic indicators can result in waste that is both environmentally harmful and costly. The butterfly pea flower is one of the plants that contains anthocyanins, which have the potential to be used as an alternative indication of natural acids and bases. The study aims to determine the acid and base material curriculum and competency indicators, as well as the potential of butterfly pea flower extract as a substitute for synthesis indicators and the practicality of butterfly pea flower extract as a chemical experimental design in SMA/MA. This study employs a descriptive qualitative research method that includes literature review, observation, experimentation, and interviewing. The results showed that the relationship between acid-base materials and experiments was the determination of natural materials as acid-base indicators, the pH of the solution, the identification of acid-base properties, and acid-base titration. The butterfly pea flower indicator was produced from maceration extraction using 96% ethanol as the solvent. The butterfly pea flower indicator gives pink color at pH 1-2, reddish purple at pH 3, light purple at pH 4-5, turquoise at pH 6, bluish green at pH 7, light blue at pH 8-9, green at pH 10, yellowish green at pH 11, greenish yellow at pH 12-13, and yellow at pH 14. The titration step showed that butterfly pea flower indicators could replace synthetic indicators, namely phenolphthalein and methyl orange. Based on the analysis, the butterfly pea flower indicator can be used as an alternative indicator in acid base titration and an alternative experimental design in schools.

scholarly journals Isolation of Natural Acid Base Indicator from the Flower Extract of Sarca Asoca, Abelmoschus Esulentus, Hibisucs Cannabinus And Hibiscus Rosa Sinensis

2021 ◽  
pp. 132-134
Author(s):  
Deepali Mourya ◽  
Sushrut Maner ◽  
Mandar Lele
Keyword(s):  
Caustic Soda ◽  
Methanolic Extract ◽  
Hibiscus Cannabinus ◽  
Abelmoschus Esculentus ◽  
Acid Base ◽  
Saraca Asoca ◽  
Flower Extract ◽  
Synthetic Indicators ◽  
Hibiscus Rosa Sinensis ◽  
Acid Base Titration

The objective of this work is to use more plant indicators than chemical based indicators. Saraca asoca is a species of family Fabaceae and Abelmoschus esculentus and Hibiscus cannabinus is a species of family Malvaceae [1]. Indicator are very special chemicals, they change colour of the solution with change in pH by adding acid or alkali. In the present work acid base titration has been performed by using natural indicators. The natural indicator is prepared from the most commonly occurring flower Hibiscus cannabinus, Abelmoschus esculentus Saraca asoca and Hibiscus Rosa sinensis. Aqueous and methanolic extract of flower were used as natural indicator. One acid one base were selected for acid base titration. Vinegar is used as acid and caustic soda is used as base. The results obtained by the natural indicator are almost similar to the result given by the synthetic indicators. Thus, natural indicator from flowers can be used for acid base titration [2]. Using aqueous extract of flower as indicator is more economical and with the same accuracy of result as that given by synthetic indicators.

scholarly journals Separation of Sn, Sb, Bi, and Cu from Tin Anode Slime by Solvent Extraction and Chemical Precipitation

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 515
Author(s):  
Wei-Sheng Chen ◽  
Shota Mesaki ◽  
Cheng-Han Lee
Keyword(s):  
Solvent Extraction ◽  
Liquid Phase ◽  
Ph Value ◽  
Chemical Precipitation ◽  
Extraction Process ◽  
Refining Process ◽  
Anode Slime ◽  
Electrolytic Refining ◽  
Precipitation Procedure ◽  
Tin Anode

Tin anode slime is a by-product of the tin electrolytic refining process. This study investigated a route to separate Sn, Sb, Bi, and Cu from tin anode slime after leaching with hydrochloric acid. In the solvent extraction process with tributyl phosphate, Sb and Sn were extracted into the organic phase. Bi and Cu were unextracted and remained in the liquid phase. In the stripping experiment, Sb and Sn were stripped and separated with HCl and HNO3. Bi and Cu in the aqueous phase were also separated with chemical precipitation procedure by controlling pH value. The purities of Sn, Sb, Cu solution and the Bi-containing solid were 96.25%, 83.65%, 97.51%, and 92.1%. The recovery rates of Sn, Sb, Cu, and Bi were 76.2%, 67.1%, and 96.2% and 92.4%.

scholarly journals Lewis acid / Base-free Strategy for the Synthesis of 2-Arylthio and Selenyl Benzothiazole / Thiazole and Imidazole

2021 ◽  
Vol 27 (1) ◽  
pp. 17-23
Author(s):  
Guniganti Balakishan ◽  
Gullapalli Kumaraswamy ◽  
Vykunthapu Narayanarao ◽  
Pagilla Shankaraiah
Keyword(s):  
Lewis Acid ◽  
Bond Formation ◽  
Acid Base ◽  
Mechanistic Pathway ◽  
Wide Range ◽  
Acid And Base ◽  
Lewis Acid And Base ◽  
Sulfur Bond

Abstract A Cu(II)-catalyzed Csp2-Se and Csp2-Sulfur bond formation was achieved with moderate to good yields without the aid of Lewis acid and base. The reaction is compatible with a wide range of heterocycles such as benzothiazole, thiazole, and imidazole. Also, this typical protocol is found to be active in thio-selenation via S-H activation. Additionally, we proposed a plausible mechanistic pathway involving Cu(III) putative intermediate.

scholarly journals Electronic, Structural, and Optical Structure of Mono-Doped and Co-Doped (210) TiO2 Brookite Surfaces for Application in Dye-Sensitized Solar Cells—A First Principles Study

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3918
Author(s):  
Ratshilumela S. Dima ◽  
Lutendo Phuthu ◽  
Nnditshedzeni E. Maluta ◽  
Joseph K. Kirui ◽  
Rapela R. Maphanga
Keyword(s):  
Solar Cells ◽  
Band Gap ◽  
Dye Sensitized Solar Cells ◽  
Visible Region ◽  
Electromagnetic Spectrum ◽  
Doped Tio2 ◽  
Dye Sensitized ◽  
Sensitized Solar Cells ◽  
Co Doped ◽  
Optical Structure

Titanium dioxide (TiO2) polymorphs have recently gained a lot of attention in dye-sensitized solar cells (DSSCs). The brookite polymorph, among other TiO2 polymorphs, is now becoming the focus of research in DSSC applications, despite the difficulties in obtaining it as a pure phase experimentally. The current theoretical study used different nonmetals (C, S and N) and (C-S, C-N and S-N) as dopants and co-dopants, respectively, to investigate the effects of mono-doping and co-doping on the electronic, structural, and optical structure properties of (210) TiO2 brookite surfaces, which is the most exposed surface of brookite. The results show that due to the narrowing of the band gap and the presence of impurity levels in the band gap, all mono-doped and co-doped TiO2 brookite (210) surfaces exhibit some redshift. In particular, the C-doped, and C-N co-doped TiO2 brookite (210) surfaces exhibit better absorption in the visible region of the electromagnetic spectrum in comparison to the pure, S-doped, N-doped, C-S co-doped and N-S co-doped TiO2 brookite (210) surfaces.

One-pot synthesis of furfural derivatives from pentoses using solid acid and base catalysts

2014 ◽  
Vol 4 (4) ◽  
pp. 971-978 ◽  
Author(s):  
Mahiro Shirotori ◽  
Shun Nishimura ◽  
Kohki Ebitani
Keyword(s):  
Solid Acid ◽  
Acid Base ◽  
One Pot ◽  
Amberlyst 15 ◽  
Base Catalysts ◽  
One Pot Synthesis ◽  
Combined Use ◽  
Acid And Base

One-pot synthesis of (2-furanylmethylene)malononitrile, a Knoevenagel product of furfural with malononitrile, from xylose efficiently proceeded by combined use of acid Amberlyst-15 and acid-base Cr/hydrotalcites in 44% yield.

Emergent chiroptical properties in supramolecular and plasmonic assemblies

2021 ◽  
Author(s):  
N. S. Shahana Nizar ◽  
Meleppatt Sujith ◽  
K. Swathi ◽  
Cristina Sissa ◽  
Anna Painelli ◽  
...  
Keyword(s):  
Visible Region ◽  
Electromagnetic Spectrum ◽  
Comprehensive Description ◽  
Chiroptical Properties ◽  
Uv Visible

This tutorial provides a comprehensive description of the origin of chiroptical properties of supramolecular and plasmonic assemblies in the UV–visible region of the electromagnetic spectrum.

Light-induced change of the molecular charge in a spironaphthoxazine compound

1993 ◽  
Vol 71 (11) ◽  
pp. 1828-1833 ◽  
Author(s):  
Paul Rys ◽  
Ruth Weber ◽  
Qinglan Wu
Keyword(s):  
Flash Photolysis ◽  
Ph Value ◽  
Uv Light ◽  
Merocyanine Form ◽  
Acid Base ◽  
Experimental Conditions ◽  
Base Equilibrium ◽  
Acid Base Equilibrium ◽  
Molecular Charge ◽  
Spiro Form

To evaluate the experimental conditions for the light-induced change of the molecular charge, the dependence of the photochromic reaction behaviour of the indolino spiro naphthoxazine compound 1,3,3-trimethyl-spiro[2H-indol 2,3′-[3H]naphth[2,1-b]-[1,4]oxazine] on the pH value of the solution is investigated. In the absence of UV light an acid–base equilibrium between the spiro form and a protonated closed form is established. By irradiation under appropriate acidic conditions the spiro form can be transformed into an open cationic form through the merocyanine form. Between the two open forms an acid–base equilibrium is established. Except for the closed protonated form the structures are confirmed by mean of NMR. The kinetics of the thermal ring-closing reaction of both forms are investigated by flash photolysis. It is shown that the ring-closing reaction proceeds exclusively via the merocyanine form. The pK values determined for both equilibria give the pH range, in which the light-induced change of the molecular charge occurs.

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