Recent investigations have shown that application of appropriate concentrations of naphthenate induces greater growth and yield of several crop plants. However, reports are lacking on the effect of naphthenate on plants grown under various temperature and light conditions and also on physiological and biochemical changes induced in bush bean (Phaseolus vulgaris L.Var. Top Crop) plants following naphthenate treatment. In the course of the present work the following aspects were investigated: 1) juvenile growth, as measured by fresh and dry weight of roots, stem and leaves, number and area of leaflets and plant height; 2) reproductive growth, as measured by flower number, number and fresh weight of pods, and number and weight of dry seeds; 3) chemical composition, such as moisture content of roots, stem, leaves, and pods, chlorophyll and carotenoid content of leaves, ascorbic acid content of green pods and loss of ascorbic acid by pods during storage for five days, and 4) such physiological and metabolic changes as rates of apparent photosynthesis and dark respiration, activities of the enzymes nitrate reductase, glutamic-pyruvic transaminase, phosphorylase and phosphoglyceryl kinase. Subsequent to KNap treatment, plants in some experiments were grown in growth rooms provided with 26°/26°, 26°/21° and 15°/15°C, day/night temperature. At 26°/26° and 15°/15° plants were grown under three different light intensities, 1500, 1000 and 500 ft-c. The results revealed that: (1) treatment with KNap resulted in increases in plant height, number and area of leaflets, fresh and dry weight of roots, stem and leaves, and total chlorophyll content in leaves; (2) measurements made with intact plants using an infrared CO₂ analyzer revealed increases in rates of apparent photosynthesis and dark respiration in treated plants; (3) the activity of the four enzymes mentioned was stimulated in plants treated with KNap; (4) increases in number and fresh weight of green pods, number and weight of seed were observed in treated plants; (5) treatment resulted in higher ascorbic acid content in green pods at harvest and the treatment had a protective action on ascorbic acid loss during storage. Different plant organs were found to respond differently to treatment depending on temperature and light intensity in which the plants were grown. The maximum relative stimulatory effect of KNap treatment was found mostly at 26°/21° and it was followed by 26°/26° and 15°/15°, in plants grown under a light intensity of 1500 ft-c. Plants grown at 26°/26° showed maximum relative stimulation in most instances in high light. The maximum relative stimulation for plants grown at 15°/15° was in medium light generally speaking. In proposing a physiological and biochemical basis for the stimulation of growth and yield following KNap treatment, the following points may be emphasized: (a) the stimulated rate of photosynthesis produced a larger amount of photosynthate which could be utilized in the biosynthesis of all cell constituents and serve as substrate for respiration and other chemical processes; (b) the stimulated rate of respiration and activity of phosphoglyceryl kinase resulted in an increased supply of available energy, as ATP and reduced nucleotides, for biosynthesis; (c) the augmented supply of amino acids resulting from the greater activity of nitrate reductase and transaminase would be favorable for enhanced synthesis of protein, evident in stimulated growth. / Science, Faculty of / Botany, Department of / Graduate

Thesis (MScEng (Process Engineering))--University of Stellenbosch, 2009. / Aromatic precursor compounds are derivatives that play an important role in biosystems and are useful in the production of fine chemicals. This work focuses on the catalytic synthesis of 2-methyl-1, 4-naphthoquinone and cresols (para- and ortho) using aqueous hydrogen peroxide as an oxidant in liquidphase oxidation of 2-methylnaphthalene and toluene over titanium-substituted zeolite TS-1 or Ti-MCM-41. Catalysts synthesised in this work were calcined at 550°C, extensively characterised using techniques such as X-ray Fluorescence for determining the catalyst chemical composition; BET for surface area, pore size and micropore volume; Powder X-ray diffraction for determining their crystallinity and phase purity and SEM was used to investigate the catalyst morphologies. The BET surface areas for Ti-MCM-41 showed a surface area of 1025 m2/g, and a 0.575 cm3/g micropore volume. However, zeolite TS-1 showed a BET surface area of 439 m2/g and a 0.174 cm3/g micropore volume. The initial experiments on 2-methylnaphthalene hydroxylation were performed using the normal batch method. After a series of batch runs, without any success as no products were generated as confirmed by GC, a second experimental tool was proposed. This technique made use of the reflux system at reaction conditions similar to that of the batch system. After performing several experimental runs and optimising the system to various reactor operating conditions and without any products formed, the thought of continuing using the reflux was put on hold. Due to this, a third procedure was brought into perspective. This process made use of PTFE lined Parr autoclave. The reactor operating conditions were changed in order to suit the specifications and requirements of the autoclave. This process yielded promising results and the formation of 2-MNQ was realised. There was a drawback when using an autoclave as only one data point was obtained, at the end of each run. Therefore, it was not possible to investigate reaction kinetics in terms of time. Addition of aqueous hydrogen peroxide (30 wt-%) solution in the feed was done in one lot at the beginning of each reaction in all oxidation reactions, to a reactor containing 2-methylnaphthalene and the catalyst in an appropriate solvent of choice (methanol, acetonitrile, 2-propanol, 1-propanol, 1-pentanol, and butanol), with sample withdrawal done over a period of 6 hours (excluding catalytic experiments done with a Parr autoclave as sampling was impossible). As expected, 2-methylnaphthalene oxidation reactions with medium pore zeolite TS-1 yielded no formation of 2-methyl-1, 4-naphthoquinone using various types of solvents, with a batch reactor, reflux system, or a Parr PTFE autoclave. This was attributed to the fact that 2-methylnaphthalene is a large compound and hinders diffusion into zeolite channels. With the use of an autoclave, Ti-MCM-41 catalysed reactions showed that the choice of a solvent and reaction temperature strongly affect 2- methylnaphthalene conversion and product selectivity. This was proven after comparing a series of different solvents (such as methanol, isopropanol, npropanol, isobutanol, n-pentanol and acetonitrile) at different temperatures. Only reactions using acetonitrile as a solvent showed 2-MNQ. Formation of 2- MNQ, indicating that acetonitrile is an appropriate choice of solvent for this system. The highest 2-methylnaphthalene conversion (92%) was achieved at 120 ˚C, with a relative product selectivity of 51.4 %. Temperature showed a major effect on 2-MN conversion as at lower reaction temperature 100˚C, the relative product selectivity (72%) seems to enhance; however, the drawback is the fact that lower 2-methylnaphthalene conversions (18%) are attained. Another important point to note is the fact that using an autoclave (with acetonitrile as a solvent), 2-methyl-1-naphthol was generated as a co-product. In conclusion, it has been shown that the hydroxylation of different aromatic compounds over zeolites conducted in this study generated interesting findings. In 2-MN hydroxylation over Ti-MCM-41 as a catalyst, only acetonitrile is an appropriate choice of solvent using an autoclave. In addition, zeolite TS-1 is not a suitable catalyst for 2-MN hydroxylation reactions. It is ideal to optimise an autoclave in order to investigate reaction kinetics and optimum selectivity. Toluene hydroxylation reactions yielded para and ortho-cresol as expected with either water or acetonitrile as a solvent. No meta-cresol was formed. The kinetic model fitted generated a good fit with water as a solvent or excess toluene, with acetonitrile as a solvent generating a reasonable fit.