Browsing by Author "Nambela, Lutamyo"

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    Levels and chemo dynamics of pesticide residues in eastern lake Tanganyika basin, Tanzania
    (Unversity of Dar es Salaam, 2014) Nambela, Lutamyo
    This thesis reports on levels and chemodynamics of pesticide residues in eastern Lake Tanganyika basin of Tanzania. The aim of this study was to investigate the types, levels and distribution of pesticide residues in environmental samples. Water, soil, sediments and fish samples were collected from Kigoma region during April and June and analysed for pesticide residues. Six different types of pesticide residues and metabolites were detected, namely, p,p’-DDT, o,p’-DDT, p,p’-DDE, p,p’-DDD, diazinon and chlorpyrifos. DDT, DDD and DDE were the predominantly detected compounds in all of the samples. Diazinon and chlorpyrifos were detected in soil samples collected from vegetable and coffee farms. The highest concentrations of total DDT in sediment, soil, fish and water samples were up to 120 µg/kg dw, 564.13 µg/kg dw, 339 µg/kg fw and 221 ng/L, respectively. Chlorpyrifos and diazinon had concentrations up to 184 and 36 µg/kg dw, respectively. The distribution of DDT residues levels among sample matrices were soil > fish > sediment > water. Highest concentrations of DDT residues were detected in soil samples collected from tobacco farms and lowest concentrations of DDT residues were detected in water samples collected from tomato farm. The ratios of (p,p’- DDE + p,p’-DDD)/p,p’-DDT indicate recent inputs in most samples. The study reveals that there is recent use of DDT, diazinon and chlorpyrifos in Kigoma region. Continued use of DDT indicates risks and may result into serious environmental problems. The area therefore needs serious environmental monitoring
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    Synthesis of anthraquinone based dyes from anacardic Acid component of cashew nut shell liquid (CNSL) for Textiles applications
    (University of Dar es salaam, 2020) Nambela, Lutamyo
    The aim of this study was to develop a method for the synthesis of anthraquinone based dyes from anacardic acid isolated from CNSL and then to test the performance of the synthesised dyes on textile fabrics. CNSL was extracted in 20% yield from CNSs using petroleum ether as the solvent. Anacardic acid was then isolated from CNSL through the addition of Ca(OH)2 to form calcium anacardate and then acidification with HCl to recover the anacardic acid in 64% yield. With anacardic acid in hand, a procedure was developed for its conversion to phthalic anhydride and then anthraquinone dyes. Conversion of anacardic acid to a 3-methoxyphthalic anhydride in overall yield of 9% involved methylation of the two hydroxyl groups, alkene reduction, benzylic bromination, elimination of HBr, ozonolysis, oxidation and acid anhydride formation. The prepared 3-methoxyphthalic anhydride was subsequently reacted with benzene and substituted benzenes in the presence of AlCl3 to give three anthraquinone dyes or dye intermediates namely 1-hydroxyanthraquinone, 7-bromo-1-hydroxyanthraquinone and 1,7-hydroxyanthrquinone in 40%, 39% and 15% yields, respectively. Subsequently, 1-aminoanthraquinone was prepared in 80% yield from 1-hydroxyanthraquinone. Dimerisation of 1-aminoanthraquinone gave indanthrone in 93%. The prepared dyes were characterised using melting point measurements, UV, IR, NMR and mass spectrometry. The three prepared anthraquinone dyes were tested on 100% polyester fabric while the indanthrone dye was tested on 100% cotton fabric. 1-hydroxyanthraquinone and 7-bromo-1-hydroxyanthraquinone dyes gave yellow shade on the fabric, while 1-aminoanthraquinone gave an orange shade. Indanthrone on the other hand gave blue shade on 100% cotton fabric. The affinity of the dyes to the fabrics were determined using colour yield values which were measured using a reflectance spectrophotometer. All the dyes showed high affinity to dyed fabrics and this demonstrates that CNSL has a potential as a source of a precursor of intermediates in the synthesis of dyes.
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    Synthesis of anthraquinone based dyes from anacardic Acid component of cashew nut shell liquid (CNSL) for Textiles applications
    (University of Dar es salaam, 2020) Nambela, Lutamyo
    The aim of this study was to develop a method for the synthesis of anthraquinone based dyes from anacardic acid isolated from CNSL and then to test the performance of the synthesised dyes on textile fabrics. CNSL was extracted in 20% yield from CNSs using petroleum ether as the solvent. Anacardic acid was then isolated from CNSL through the addition of Ca(OH)2 to form calcium anacardate and then acidification with HCl to recover the anacardic acid in 64% yield. With anacardic acid in hand, a procedure was developed for its conversion to phthalic anhydride and then anthraquinone dyes. Conversion of anacardic acid to a 3-methoxyphthalic anhydride in overall yield of 9% involved methylation of the two hydroxyl groups, alkene reduction, benzylic bromination, elimination of HBr, ozonolysis, oxidation and acid anhydride formation. The prepared 3-methoxyphthalic anhydride was subsequently reacted with benzene and substituted benzenes in the presence of AlCl3 to give three anthraquinone dyes or dye intermediates namely 1-hydroxyanthraquinone, 7-bromo-1-hydroxyanthraquinone and 1,7-hydroxyanthrquinone in 40%, 39% and 15% yields, respectively. Subsequently, 1-aminoanthraquinone was prepared in 80% yield from 1-hydroxyanthraquinone. Dimerisation of 1-aminoanthraquinone gave indanthrone in 93%. The prepared dyes were characterised using melting point measurements, UV, IR, NMR and mass spectrometry. The three prepared anthraquinone dyes were tested on 100% polyester fabric while the indanthrone dye was tested on 100% cotton fabric. 1-hydroxyanthraquinone and 7-bromo-1-hydroxyanthraquinone dyes gave yellow shade on the fabric, while 1-aminoanthraquinone gave an orange shade. Indanthrone on the other hand gave blue shade on 100% cotton fabric. The affinity of the dyes to the fabrics were determined using colour yield values which were measured using a reflectance spectrophotometer. All the dyes showed high affinity to dyed fabrics and this demonstrates that CNSL has a potential as a source of a precursor of intermediates in the synthesis of dyes.