Chemical Yields Research Articles

Kinetically Controlled Stereoselective Synthesis of 2-Oxo-2-aryl-1,3,2-dioxaphosphorinane Derivatives via a Palladium-Catalyzed Reaction.

Chiral phosphonate esters have been widely applied in the fields of organic chemistry, medicine, and photoelectric materials. However, it requires the challenging enantioselective synthesis of cyclic phosphonate esters with the desired chiral configuration. The two epimers of 2-oxo-2H-1,3,2-dioxaphosphorinane derivatives should have different reactivities in Pd-catalyzed coupling reactions, which could lead to an effective methodology for the asymmetric synthesis of 2-oxo-2-aryl-1,3,2-dioxaphosphorinane derivatives. A thorough investigation of the coupling reactions both computationally and experimentally led to the stereoselective synthesis of chiral cyclic phosphonate esters. The axial isomer of products can be obtained with both high diastereoselectivity and good chemical yields from the mixture of 2-oxo-2H-1,3,2-dioxaphosphorinane derivatives under kinetically controlled conditions.

Production and radiochemical separation of 68Ge from irradiated Ga–Ni alloy target in 30 MeV cyclotron

Abstract Gallium-68 [t 1/2: 67.7 min, β+ (89 %)] has application in PET imaging mainly for prostate cancer and neuroendocrine tumours. Gallium-68 is generally obtained from a 68Ge/68Ga generator. It is therefore an important task to prepare 68Ge (t 1/2 = 271 days) radiochemical for the manufacture of 68Ge/68Ga generator to cater for the needs of various nuclear medicine centres. Germanium-68 has been produced successfully after irradiation of indigenously developed Ga–Ni targets in a 30 MeV cyclotron and chemical processing of the irradiated targets using an indigenous semi-automated module. The Ga–Ni targets were prepared by an electroplating method. The 68Ge has been radiochemically separated from irradiated Ga–Ni targets using Sephadex G-25 column chromatography. The chemical separation yield and radionuclidic purity of 68Ge were about 70 % (n = 3) and about 98.3 % (n = 3), respectively.

Influence of interactions between bubbles on physico-chemical effects of acoustic cavitation

Ultrasound technology has been extensively used as one of the efficient and economic methodology to achieve the desired outcomes in many applications by harnessing the physico-chemical effects of acoustic cavitation. However, the cavitation-associated effects, primarily determined by the oscillatory dynamics of cavitation bubbles, are considerably complex and still remain poorly understood. The main objective of this study was to perform a numerical analysis of the acoustic cavitation (i.e., the cavitation dynamics, the resultant temperature, pressure and chemical yields within collapsing bubbles), particularly focusing on the influence of the interactions between bubbles. A comprehensive model was developed to simulate the acoustic cavitation dynamics via combining the influences of mass transfer, heat conduction and chemical reactions as well as the interaction effects between bubbles. The results demonstrated that only the large bubble exerts a greater impact on the small one in a two-bubble system. Specifically, within parameter ranges covered this study, there are noticeable decreases in the expansion ratio of the small bubble, the resultant temperature, pressure and molar yields of free radicals, hence weakening the cavitation intensity and cavitation- associated physico-chemical effects. Moreover, the influences of the interactions between bubbles were further assessed quantitatively under various parameters, such as the ultrasound amplitude PA and frequency f, the distance between bubbles d0, the initial radius of the large bubble R20, as well as the liquid properties (e.g., surface tension σ and viscosity μ). It was found that the suppression effect can be amplified when subjected to ultrasound with an increased PA and/or a decreased f, probably due to a stronger cavitation intensity under this condition. Additionally, the suppression effect is also enhanced with a decrease in d0, σ and μ, but with R20 increasing. This study can contribute to deepening knowledge about acoustic cavitation and the resultant physical and/or chemical effects, potentially further facilitating the ultrasound-assisted various applications involving acoustic cavitation.

Study of grain-patterned and highly ordered L10-FePt HAMR media using reactive molecular dynamics method

Embedded Mask Patterning (EMP) has been proposed as a cost-effective fabrication method to be capable of patterning sub-5-nm grain sizes for highly ordered L10-FePt media for Heat-Assisted Magnetic Recording (HAMR). Understanding the etching mechanism of FePt is critical to maintaining the highly ordered L10 structure and low damage to magnetic grains. In this research, a reactive Molecular Dynamics (MD) model is developed to study methanol (MeOH) plasma etching on highly ordered continuous L10-FePt media film. The model describes the reactive interaction mechanism between the plasma products CO/H2 molecules and Fe/Pt atoms. It shows the dominant Fe-C interaction upon the dissociation of CO ligands leads to formation of large and volatile Fen-C clusters contributing to high chemical etch yield.

Vilsmeier Haack Reaction: An Exemplary Tool for Synthesis of different Heterocycles

Abstract: Heterocyclic compounds and their derivatives epitomize the building blocks of many biological entities, e.g., alkaloids, antibiotics, enzymes, hormones, vitamins, and others that are abundant in nature. The Vilsmeier-Haack reaction has fascinated organic chemists due to its significant use in the synthesis of numerous heterocycles. This analytical evaluation provides a scrutinized overview of the literature on the synthesis of heterocyclic compounds. : A comprehensive review of the literature related to Vilsmeier- Haack reagents and reactions is done from PubMed and other sources like google scholar and Google websites. : This precise analytic evaluation provides a revolutionary update on the Vilsmeier-Haack reaction and its applications in the synthesis of natural and synthetic compounds. : Presently researchers are developing and looking for unconventional reagents that are inexpensive, have high chemical yields, are environmentally benign, recyclable, and robust. The information incorporated in this review paper may inspire more research on the Vilsmeier-Haack reagent and its usage in heterocycle synthesis.

Soil erosion management using The Soil and Water Assessment Tool (SWAT) model in Semantok Watershed

The land use characteristics in the Semantok watershed have a significant impact on the reservoir's usable age. According to the land use patterns, including teak woods, rice fields, moorlands, dry fields, and residential areas, the Semantok watershed has the capacity to carry sediment when it rains. One of the models to analyze surface runoff and sediment is the Soil and Water Assessment Tool (SWAT). SWAT was developed to predict the impact of land management practices on water, sediment and agricultural chemical yields in large complex watersheds with varying soils, land use and management conditions over long periods of time. The purpose of this research is to quantify the amount of erosion and sedimentation that results from land use changes in the Semantok watershed in 2015 and 2021 and to determine management scenarios that can reduce the value of erosion and sedimentation that can implemented upstream of the Semantok dam using SWAT. The data used for the research are climatology data, DEM map, landuse map, and river data. The amount of erosion at the Semantok watershed outlet increased from 7.00 mm/year in 2015 to 14.18 mm/year in 2021. Based on Forestry Ministerial Regulation No. P.61/Menhut-II/2014, the Semantok watershed's carrying capacity is 3.95 falling into the pretty bad category (3.5 < DDD < 4.3). Three scenarios were compared in order to carry out control efforts: revegetation, check dams, and combining revegetation and check dams. The most efficient way to reduce erosion by up to 30.51% is to combine revegetation and check dam.

14N to 15N Isotopic Exchange of Nitrogen Heteroaromatics through Skeletal Editing.

The selective modification of nitrogen heteroaromatics enables the development of new chemical tools and accelerates drug discovery. While methods that focus on expanding or contracting the skeletal structures of heteroaromatics are emerging, methods for the direct exchange of single core atoms remain limited. Here, we present a method for 14N → 15N isotopic exchange for several aromatic nitrogen heterocycles. This nitrogen isotope transmutation occurs through activation of the heteroaromatic substrate by triflylation of a nitrogen atom, followed by a ring-opening/ring-closure sequence mediated by 15N-aspartate to effect the isotopic exchange of the nitrogen atom. Key to the success of this transformation is the formation of an isolable 15N-succinyl intermediate, which undergoes elimination to give the isotopically labeled heterocycle. These transformations occur under mild conditions in high chemical and isotopic yields.

Plastic Waste Conversion by Leveraging Renewable Photo/Electro-Catalytic Technologies.

Plastics have revolutionized our lives; however, the exponential growth of their usage has led to a global crisis. More sustainable strategies are needed to address this dilemma and transform the plastics economy from a linearity to a circular model. Herein, we systematically summarize the recent progress in renewable energy-driven plastic conversion strategies, including photocatalysis, electrocatalysis, and their integration. By introducing the significant works, the design principles, mechanisms, and system regulations, we decipher and compare the various aspects of plastic conversion. These approaches show high reactivity and selectivity under environmentally benign conditions and provide alternative reaction pathways for plastic conversion. Plastic upcycling as a chemical feedstock can yield value-added chemicals and fuels, contributing to the establishment of a sustainable and circular economy. Additionally, several innovations in reaction engineering and system designs are presented. Finally, the challenges and perspectives of sustainable energy-driven plastic conversion technologies are comprehensively discussed.

Optimization of Initial Cell Density and Usage Efficiency of Seed Culture Medium During Lipid Production from Distillery Wastewater by Rhodosporidium toruloides

For the environmentally sustainable development, the recovery of resource or energy from wastes has attracted worldwide attention in recent years. The wastewater produced from distillery is more difficult to treat than the domestic wastewater due to the high organic loads. This study explores the possibility of developing a process, which could produce microbial lipid convertible to biodiesel by recovering nutrients from non-sterile wastewater while simultaneously removing part of organic matters through cultivating oleaginous microorganisms. Especially, it is intended to further optimize the initial cell density and the usage efficiency of seed culture medium. The lipid productivity by oleaginous yeast Rhodosporidium toruloides was studied using wastewater from rice wine distillery, at 30ºC under different initial cell densities (2 x 107, 1 x 107, 0.8 x 107, and 0.5 x 107 cells/mL) and incubation periods (2-5 days). Chemical oxygen demand (COD) removal efficiency, cell yield, and lipid yield were analyzed and the potential for bioenergy recovery from wastewater was assessed. The seed culture medium was found reusable for the second time without the addition of extra nutrient and possible for the third time with the addition of glucose.

Studies of chemical bonds loss and optical modifications of CR-39 caused by gamma rays

The induced impacts of high doses of gamma irradiation on the structural variations of poly-allyl-diglycol carbonate (PADC) polymers (CR-39) were studied in terms of X-ray diffraction (XRD) patterns. CR-39 samples were irradiated separately at different ranging from 200 to 800 kGy; (step 200). A deconvolution process of the XRD spectra of CR-39 samples for all gamma irradiation doses was performed. The results of this deconvolution process for the pristine specimen show three diffraction peaks at about 20.30°, 28.16° and 41.70° of 2θ. The broad peaks at 28.16o and 41.70°, and the highest peak at 20.30° of XRD confirm the amorphous nature and low degrees of crystallinity, respectively. The position, area, intensity and full width at half maximum of these peaks are changed with further doses of gamma irradiation. With additional gamma irradiations, the intensities of all peaks decrease significantly. The highest and sharpest peak properties are employed to determine the crystallinity, crystallite size, and radiation chemical yield (G-value) for the loss of carbonate ester bonds using a proposed method. Higher doses of gamma irradiation result in a decrease in crystallinity while increasing crystallite size. Furthermore, the optical band gaps reduced from 4.81 to 3.49 eV when the irradiated dose increased from 0 to 800 kGy. Furthermore, the third order nonlinear susceptibility increased from 0.84x10−12 esu to 2.25x10−12 esu with increasing the radiation doses from 0 to 800 kGy. Moreover, the nonlinear refractive increased from 1.52x10−11 to 3.69x10−11 with increasing the radiation doses from 0 to 800 kGy. On the other hand, the number of carbon atoms in each cluster increased from 51 to 97 when the irradiated dose increased from 0 kGy to 800 kGy.

Sequential catalytic lignin valorization and bioethanol production: an integrated biorefinery strategy

BackgroundThe effective valorization of lignin and carbohydrates in lignocellulose matrix under the concept of biorefinery is a primary strategy to produce sustainable chemicals and fuels. Based on the reductive catalytic fractionation (RCF), lignin in lignocelluloses can be depolymerized into viscous oils, while the highly delignified pulps with high polysaccharides retention can be transformed into various chemicals.ResultsA biorefinery paradigm for sequentially valorization of the main components in poplar sawdust was constructed. In this process, the well-defined low-molecular-weight phenols and bioethanol were co-generated by tandem chemo-catalysis in the RCF stage and bio-catalysis in fermentation stage. In the RCF stage, hydrogen transfer reactions were conducted in one-pot process using Raney Ni as catalyst, while the isopropanol (2-PrOH) in the initial liquor was served as a hydrogen donor and the solvent for lignin dissolution. Results indicated the proportion of the 2-PrOH in the initial liquor of RCF influenced the chemical constitution and yield of the lignin oil, which also affected the characteristics of the pulps and the following bioethanol production. A 67.48 ± 0.44% delignification with 20.65 ± 0.31% of monolignols yield were realized when the 2-PrOH:H2O ratio in initial liquor was 7:3 (6.67 wt% of the catalyst loading, 200 °C for 3 h). The RCF pulp had higher carbohydrates retention (57.96 ± 2.78 wt%), which was converted to 21.61 ± 0.62 g/L of bioethanol with a yield of 0.429 ± 0.010 g/g in fermentation using an engineered S. cerevisiae strain. Based on the mass balance analysis, 104.4 g of ethanol and 206.5 g of lignin oil can be produced from 1000 g of the raw poplar sawdust.ConclusionsThe main chemical components in poplar sawdust can be effectively transformed into lignin oil and bioethanol. The attractive results from the biorefinery process exhibit great promise for the production of valuable biofuels and chemicals from abundant lignocellulosic materials.

Combined lime and biochar application enhances cowpea growth and yield in tropical Alfisol

It is essential to increase the pH of tropical soils in order to reduce acidity and promote soil and crop productivity. Therefore, experiments were carried out in 2020 and 2021 to assess the impacts of biochar and lime on the chemical properties, growth, nodulation, and yield of cowpea (Vigna unguiculata). The study involved various levels of lime (CaCO3) and wood biochar (ranging from 0 to 10 t ha−1), organized in a factorial combination. The treatments were arranged in a randomized complete block design and replicated three times. The application of lime and biochar, either separately or in combination, led to improvements in soil chemical properties such as pH, nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), sodium (Na), magnesium (Mg), and cation exchange capacity (CEC), as well as enhancements in the growth, nodulation, and yield of cowpea when compared to the control. Lime and biochar alone and combined reduced exchangeable acidity (Al + H) relative to the control. Cowpea yield increased with lime rate up to a point, but then decreases. The highest cowpea yield is achieved at a lime rate of 2.5 t ha−1, whereas cowpea yield increased as the Biochar rate increased from 0 up to 10 t ha−1. There was a significant correlation between pH and cowpea pod weight in both years (2020 and 2021). The R values were − 0.615 and − 0.444 for years 2020 and year 2021 respectively at P < 0.05. At higher lime levels combined with biochar, there were considerable reductions in cowpea yield, and this decrease can be attributed to unfavorable soil pH conditions. Relative to 2.5 t ha−1 lime + 5 t ha−1 biochar, 10 t ha−1 lime + 10 t ha−1 biochar, reduced cowpea grain yield by 853% in 2020 and 845% in 2021. Since there were no significant differences between the effects of 2.5 t ha−1 lime + 5 t ha−1 biochar, 2.5 t ha−1 lime + 7.5 t ha−1 biochar, and 2.5 t ha−1 lime + 10 t ha−1 biochar applications on cowpea yield, therefore to prevent waste of Biochar, 2.5 t ha−1 lime + 5 t ha−1 biochar is recommended for production of cowpea.

An Experimental and Computational Approach to The Microwave‐Assisted Synthesis of 2’‐Hydoxychalcone Derivatives in 1‐Dodecyl‐3‐Methylimidazolium Bromide ([DDMIm]Br) Ionic Liquids

AbstractFour derivatives of 2’‐hydoxychalcone were synthesized through Claisen‐Schmidt condensation by combining 2’‐hydroxyacetophenone and four different benzaldehyde derivatives (o‐vanillin, salicylaldehyde, p‐anisaldehyde, and benzaldehyde) in the presence of a base. The reactions took place in an ionic liquid, 1‐dodecyl‐3‐methylimidazolium bromide ([DDMIm]Br), and were facilitated by microwave irradiation. The reactions were completed within 10 to 15 minutes, yielding products with chemical yields ranging from 52.64 % to 83.42 %. The structures of the synthesized products were confirmed using 1H NMR and 13C NMR spectroscopy. Additionally, antimicrobial activity tests demonstrated the effectiveness of specific derivatives against Staphylococcus aureus and Escherichia coli, underscoring the importance of hydroxy and methoxy groups on the aromatic ring in inhibiting microbial growth. These findings provide valuable knowledge for developing chalcone derivatives with improved properties and potential applications in drug discovery. Furthermore, the synthesized products′ reactivity was analyzed using Frontier Molecular Orbital (FMO) and their reactivity site was mapped using Molecular Electrostatic Potential (MEP). Lastly, molecular docking analysis was attempted to explain antibacterial activities from all products. Nonetheless, the molecular docking simulations conducted in this study were inadequate to fully account for the antimicrobial activity observed in all the products.

Effect of Three Different Nitrogen Rates and Three Rhizosphere N2- Fixing Bacteria on Growth, Yield and Quality of Peanuts

Raising prices of organic fertilizers, environmental relation of their usage and need for global foodstuff, placed a topic of universal interest in cultivation of legume plants for human nutrients and soil fertility supplementation. Three rates of N fertilizer were studied in the field: 0, 20 and 40 kg N/ha. Three bacterial strains were identified and inoculated in the experiment: Enterobacter asburiae (E. asburiae), Klebsiella quasipneumoniae (K. quasipneumoniae) and Enterobacter cloacae (E. cloacae). The soil samples were taken before and after experiment for chemical attributes analysis. The effect of N2 fertilizer and 3 bacterial strains was on soil chemical properties, yield components and yield of peanut plant. The results of present study showed that application of different N2 fertilizer rates was a little influence on the N2-fixing ability of rhizosphere bacteria, but high effect was significant at the peanut nodule number. In the 3 N fertilizer rates and 3 bacteria, which only had N2 fertilizer rate of 40 kg N/ha and E. asburiae significantly raised the maximum yield component and yield of peanut, while there was the lowest yield component and yield of peanut was observed in N fertilizer rate application of 0 kg N/ha and E. cloacae inoculation. The differences in rhizosphere bacterium strains between different N fertilizer rates was better than that caused by the nitrogen fertilizer amount. This could be due to the substantial improvement in soil chemical attributes at different soils, especially in, pH, OM and total N, as these significantly impacted the soil structure. HIGHLIGHTS Increasing pH, organic matter and total nitrogen of soil were statistically significantly different by 3 N2 fertilizer rates. There is a positive interaction between nitrogen rates and RNFB increasing yield of peanut. Number and weight of peanut nodules obtained the maximum value without applying N2 application compare to other treatments. The maximum yield components of peanut were inoculated with asburiae to compare with K. quasipneumoniae and E. cloacae and applied weight of 40 kg N/ha. The maximum yield of peanut was inoculated with asburiae to compare with K. quasipneumoniae and E. cloacae. GRAPHICAL ABSTRACT

Verification of Vermicompost Technology on Faba Bean Production at Welmera District, Birbo Watershed, Central Highlands of Ethiopia

Vicia faba, usually known as faba bean, which is commonly cultivated as a crop for human consumption, is the world’s leading source of protein. However, due to the low availability of basic cations, excess of hydrogen and aluminium in exchangeable forms, soil fertility limits its productive potential. Thus, this verification trial was intended to show the effects of Vermicompost technology on faba bean production, productivity and soil properties improvement on Nitisol of Birbo watershed in Welmera district in 2020/23. This verification work indicated that vermicompost application had contributed to the improvement of soil’s chemical properties and yields of faba bean, even if statistically non-significant results were observed. Soil chemical properties like pH, TN and OC were observed due to their application. From this study it is concluded that fifty per cent of nitrogen (0.47 ton ha-1) from Vermicompost and fifty per cent of nitrogen from urea would be recommended to be applied in the areas which have the same agro-ecology and soil properties as Welmera Districts.

The Effects of Particle LET and Fluence on the Complexity and Frequency of Clustered DNA Damage.

Clustered DNA-lesions are predominantly induced by ionizing radiation, particularly by high-LET particles, and considered as lethal damage. Quantification of this specific type of damage as a function of radiation parameters such as LET, dose rate, dose, and particle type can be informative for the prediction of biological outcome in radiobiological studies. This study investigated the induction and complexity of clustered DNA damage for three different types of particles at an LET range of 0.5-250 keV/μm. Nanometric volumes (36.0 nm3) of 15 base-pair DNA with its hydration shell was modeled. Electron, proton, and alpha particles at various energies were simulated to irradiate the nanometric volumes. The number of ionization events, low-energy electron spectra, and chemical yields for the formation of °OH, H°, , and H2O2 were calculated for each particle as a function of LET. Single- and double-strand breaks (SSB and DSB), base release, and clustered DNA-lesions were computed from the Monte-Carlo based quantification of the reactive species and measured yields of the species responsible for the DNA lesion formation. The total amount of DNA damage depends on particle type and LET. The number of ionization events underestimates the quantity of DNA damage at LETs higher than 10 keV/μm. Minimum LETs of 9.4 and 11.5 keV/μm are required to induce clustered damage by a single track of proton and alpha particles, respectively. For a given radiation dose, an increase in LET reduces the number of particle tracks, leading to more complex clustered DNA damage, but a smaller number of separated clustered damage sites. The dependency of the number and the complexity of clustered DNA damage on LET and fluence suggests that the quantification of this damage can be a useful method for the estimation of the biological effectiveness of radiation. These results also suggest that medium-LET particles are more appropriate for the treatment of bulk targets, whereas high-LET particles can be more effective for small targets.

Gamma radiolytic degradation of catechin in aqueous solution

Catechin is a polyphenol belonging to flavan-3-ol class, most abundantly found in tea. Due to its remarkable metal chelation property, it can be used as a suitable radionuclide carrier in the field of radiopharmaceuticals. Therefore, aqueous radiation stability of catechin was studied under 60Co-γ radiation environment. The degradation efficiency was ∼20% for initial concentration of 50 mg L−1 and ∼50% for initial concentration of 25 mg L−1 with application of 1.2 kGy dose. The degradation kinetics followed the pseudo first order kinetic reaction model. The radiation chemical yield value implied that presence of reactive species from gamma-induced radiolysis of water has a profound impact on the degradation of catechin in aqueous solution. Degradation was more favoured in neutral medium compared to acidic medium. Addition of ethanol significantly decreased the degradation efficiency.

Steam explosion of lignocellulosic residues for co-production of value-added chemicals and high-quality pellets

The demand of pellets as energy carrier and the competitiveness of wood biomass are the drivers for finding alternative raw materials for production of pellets. The aim of this study was to investigate the steam explosion of lignocellulosic residues such as, straw, sawdust birch, sawdust spruce, GROT (mixture of 30 % bark and 70 % industrial chips), and their mix to co-production of value-added chemicals and high-quality pellets. The raw materials were first impregnated with water/acetic acid prior to steam explosion process, while leaching and washing of steam exploded biomass was used to reduce the ash content. The value-added chemicals were extracted with MIBK, and a gas chromatography was used to determine which value-added chemicals are present in the MIBK filtrates after extraction of the steam exploded biomass. Thermogravimetric analysis and Fourier transform infrared spectroscopy, elemental analysis, calorific values, compression strength and density were used to assess and compare the quality of steam exploded biomass and pellets quality. The results from the extraction experiments shows that furfural, HMF, vanillin, syringaldehyde and coniferaldehyde are the most value-added chemicals extracted from lignocellulosic residues where higher yield of the valuable chemicals was obtained when the biomass was presoaked in acetic acid. The ash content was reduced by 83 % for straw material by washing and leaching of steam exploded straw material when the biomass was presoaked in acetic acid. High quality pellets with high calorific value (20 MJ/kg), high compression strength (228 kN/m), high density (1300 kg/m3) and low ash content (0,06 %) were produced from sawdust spruce and GROT:Spruce mix used in our study. Based on our results, we can therefore suggest that steam explosion process of lignocellulosic residues improves the quality of the biomass to pellets production and at the same time open for the possibility to produce value-added chemicals.

Factors influencing yield, chemical composition and efficacy of essential oils

Essential oils are secondary metabolites that are produced by plants for the purpose of protection from pests, predators, attraction of pollinators and seed dispersal. The oil is produced in different parts of the plants and contains various chemical compounds that give plants a characteristic odour and flavor. These compounds vary between different plant species and also within plants of the same species. The yield and the efficacy of essential oils also vary between and within species. The variations in the essential oil compounds, the yield and the efficacy is influenced by both exogenous and endogenous factors. Endogenous factors such as plant age, plant density, plant genotype, part of the plant where the oil is extracted brings about variability in yield, chemical composition and the efficacy of essential oils. Similarly, exogenous factors such as light intensity and temperature, water availability, altitude and latitude, soil type and composition, preparation of the plant material before the essential oil extraction, method of extraction of the essential oil and the storage conditions after extraction also have a great influence on the chemical composition, yield and efficacy of essential oils. The factors then need to be moderated in order to ensure that the essential oil produced is of the quality required. Once extraction is done, proper storage conditions to avoid oxidation is necessary as the essential oils await to be used. They should be stored in dark cool conditions in tightly closed dark glass containers to ensure long term quality. Knowledge on the growth requirements of the individual plants that produce oils is necessary so as to produce quality oil.

EFFECTS OF ORGANIC AND INORGANIC FERTILIZERS ON SOIL CHEMICAL PROPERTIES AND THE YIELD OF Amaranthus species IN A CONTINUOUSLY CROPPED ULTISOL

Field and laboratory experiments were conducted to evaluate the effects of poultry manure and NPK (20:10:10) fertilizer on soil chemical properties and yield of Amaranthus species. The treatments were: T1-Control (no fertilizer), T2-NPK 20:10:10 (200kg/ha), T3-Poultry manure (5 tons/ha), T4-NPK 20:10:10 (100kg/ha) + Poultry manure (2.5 tons/ha), T5-NPK 20:10:10 (100kg/ha)+ Poultry manure (5 tons/ha), T6-NPK 20:10:10 (200kg/ha)+ Poultry manure (5 tons/ha. The experiments were laid out in a randomized complete block design (RCBD). The soil was strongly acidic, having a pH of 5.1 and low in % total Nitrogen (0.10), % organic carbon (1.13) and the exchangeable bases. From the study, the poultry manure 5t/ha + NPK (20:10:10) 100kg/ha gave the best yield of Amaranthus species, followed by poultry manure 5t/ha + NPK (20:10:10) 200kg/ha which gave an increase in soil chemical properties. It is recommended that the combination of poultry manure 5t/ha + NPK (20:10:10) 100kg/ha fertilizer could be used for profitable Amaranthus production in the study area.