Theory and Applications of Chemistry Vol. 3

Biomechanics of a Bifurcating Green Plant: The Roles of Bifurcation Angle and Soil Nature on Crops Growth and Productivity

W. I. A. Okuyade — 2019-12-10

Analytic study of the xylem flow in a bifurcating green plant is presented. The model involves a set of non-linear differential equations, which are tackled using the perturbation method of solutions. Solutions of the velocity, temperature, concentration, Nusselt and Sherwood numbers are obtained and presented graphically. It is observed that increase in the bifurcation angle increases the flow velocity and concentration, Nusselt and Sherwood numbers, whereas the soil parameter (magnetic field force) decreases the velocity and Nusselt number but increases the concentration and Sherwood number. These results have tremendous effect on the growth and yield of the plant. In particular, the increase in the transport velocity and concentration tend to increase the rate at which water and nutrients are made available to the plant, thus enhancing the growth and yield of the plant (crops); the variation in the electrolytic strength of the soil mineral salt water leading to a lower or higher Lorentz force tends to accounts for why some plants do well in some regions than in the others. Furthermore, it is seen that when the angle of bifurcation is zero (i.e. α =0) and the magnetic field and thermal diffusion parameter are neglected the flow structures.

Kinetics of Oxidation of Substituted Phenols by Potassium Bromate

Asha Mathew — 2019-12-10

Kinetic methods of analysis are now accepted as standard analytical procedures for several of reactions, especially oxidation types. Though the reaction of phenols and substituted phenols by potassium bromate is well understood as an oxidative type, there was a need to understand and more evidence required against the participation of Br₂in the increasing rate of reaction with increasing acetic acid composition in the bromate oxidation of phenols. Present work explains the strange behaviour on the basis of formation of HBrO₃ that is favoured in acidic medium.

Kinetics of oxidation of 3, 4-Dimethyl phenol, 4-sec-butyl phenol and 4-tert-butyl phenol in aqueous acetic acid - water medium in the temperature range of 308K to 321K were investigated. The reaction obeys first order kinetics with respect to [oxidant], [substrate] and [H⁺]. The active oxidising species was found to be HBrO₃. A suitable mechanism in conformity with the kinetic observation has been proposed. Various activation parameters such as energy of activation (58.59, 61, 43, 65.38 KJ/mol), enthalpy change [56.03, 58.87, 62.82 KJ/mol], free energy change (73.19, 77.17, 77.82 KJ/mol) and entropy of activation (-55.7, -59.45 and -48.78 J/mol/deg) for 3: 4-dimethyl phenol, 4-sec-butyl phenol, 4-tert-butyl phenol at 308K, were obtained. A rate law has been derived on the basis of the data. The order of reactivity among the methyl substituted phenols is 3, 4-dimethyl phenol > p-cresol > phenol. The order of reactivity among higher alkyl substituted phenols is 4-tert-butyl phenol 4-sec-butyl phenol > 4-ethyl phenol >phenol.

The Effect of Acacia senegal Leaf Extract on the Flammability of Flexible Polyurethane Foam

Baffa Abubakar — 2019-12-10

Health and environmental consequences of conventional flame retardants necessitated the incorporation of new plant based flame retardants. According to Australlian Plant Society all Acacia species can be used as fire retardants which lead to the selection of the leaves of Acacia senegal as a flame retardant on flexible polyurethane foam. GC-MS analysis revealed the presence of phosphorus and nitrogen compounds. Add on percentage ranged from 10-20%, Ignition time from 8-17 seconds, flame propagation rate ranged between 0.33-0.10 cm/s, after glow time ranged from 25-5 seconds and char formation ranged from 23-30%. The flammability characteristics of the flexible polyurethane foam was improved upon doping with the extract of the leaves of this plant.

Physico-Chemical Characterization of Chemically Precipitated Nickel in a Synthetic Aqueous Media

G. Ramiro Escudero — 2019-12-10

In the liquid-liquid and solid-liquid systems there is possible to promote the chemical precipitation of certain species by controlling the physical-chemical conditions of the liquid media. In the case of solid-liquid interactions the chemical precipitates can adsorb on the surface of particles modifying their surface properties (i.e. during milling), whereas for the liquid-liquid system this precipitation contributes to clean for instance wastewater contaminated with heavy metals.

In this work nickel sulfate hexahydrate (NiSO₄∙ 6H₂O) was dissolved in distilled water, to establish the physicochemical conditions (pH, electrochemical potential, ionic strength, activity coefficient) that enhance the chemical precipitation of nickel species.

The chemical analysis of precipitates was carried out by X-ray diffraction, Fourier transformed infrared spectrometry, and the quantitative chemical analysis of liquids was carried out by atomic absorption spectroscopy. The zeta potential of nickel precipitates was also determined.

The experimental results show that nickel precipitates as nickel hydroxide (Ni(OH)₂) starting at pH 3, being more evident at pH 9. Nickel precipitates completely at pH 11. From zeta potential measurements the surface charge goes from negative to positive with the IEP at pH around 11, such behavior is attributed to the change of nickel hydroxide type from α-Ni(OH)₂ to β-Ni(OH)₂.

The functional groups of nickel precipitates were obtained through FTIR spectrometry, where the peak at 3650 cm^-1 represents the free OH group in the β-Ni(OH)₂ phase.

From these results, there is possible to propose a cleaning route of water contaminated with nickel.

Roadside Heavy Metals in Soil and Plants

Nachana’a Timothy — 2019-12-10

Heavy metal concentration in roadside soil and plants are increasingly becoming of health concern. Especially with the continue increase in anthropogenic activities such as industries and urbanization which releases pollutants in to the environment without control and effects remedies. Heavy metal is any metal that is toxic regardless of their density or atomic mass. Heavy metals occur naturally in the soil environment from the pedogenetic processes of weathering of parent materials and from anthropogenic sources such as traffic emission, industrial and energy production, waste disposal, vehicle exhaust as well as coal and fuel combustion. Among the numerous environmental pollutants, heavy metals plays an important role as its concentrations in air, soil and water are continuously increasing due to anthropogenic activities. To determine heavy metals in roadside soil and plants, Hong major road in Adamawa State, Nigeria was taken as a case study. The concentration of selected heavy metals (Cd, Pb, Zn, Cr, Fe, Mg, Mn, Co, Ni and Cu) in roadside soils and plants samples from selected sites (Plaifu, Shiwa, Fadama-rake and Damdrai) along major road in Hong were determined. Soil samples were taken 10 m, 20 m and 30 m away from the edge of the road at the depth of 0-10 cm, 10-20 cm and 20-30 cm. Plant samples were randomly collected within the vicinity where the soil samples were taken and were analyzed using Atomic Absorption Spectrophotometer. The result revealed the trend in soil heavy metal concentration was Fe > Mn > Mg > Pb > Zn > Ni > Co > Cu > Cr > Cd and for plant the trend was Fe > Mn > Mg > Zn > Pb > Ni > Cu > Cd > Co > Cr. The concentrations decreased with increasing distance away from the edge of the road as well as with depth at which the soil sample were taken. The transfer factor showed that the concentration of Zn, Mn, Cu and Mg were greater than 1, which shows that plant were enriched by Zn, Mn, Cu and Mg from the soil. Mg and Cd equal to 1 at Plaifu and Damdrai. Most of the values of TF at the study area super pass 0.5, which implies that generally, the ability of bioaccumulation of these heavy metals in examined plants were relatively high.

Biological Studies of Newly Synthesized Benzo[d][1,2,3]triazole Derivatives

Bharti Bhardwaj — 2019-12-10

The study of heterocyclic systems provides most fascinating field for exploration in view of variety of interesting and intricate reactions, which lead to synthesis of unusual systems having diversities in their skeletal pattern. In this context, various new heterocycles and derivatives are synthesized with increased biological activities and less toxicity. Benzo-fused azoles containing three heteroatoms, specially, benzo[d][1,2,3]triazole, has received great attention, these days, for their chemical and biological properties and many of them are used as medicines for various diseases. Many researches have also shown that when heterocyclic and aliphatic secondary amines are introduced in a variety of heterocyclic compounds, the resulting compounds have been found to possess enhanced biological activities. Therefore aim of our research was to hook benzotriazole scaffold with these amines with a help of suitable linker in thirst of obtaining the resulting synthesized molecules possessing high and varied biological activities which can be useful to mankind in future. We have synthesized N-aminoalkylated derivatives of benzo[d][1,2,3]triazole. All the synthesized compounds were fully characterized on the basis of their detailed spectral studies and were evaluated for their antimicrobial activities in vitro.

Synthesis and Characterization of a Butenafine Analogue

M. A. Muhammad — 2019-12-10

Aims: The study aims: (I) To synthesise N-(4-(tert-butyl) benzyl)-1-(4-tert-butyl) phenyl)-N-methyl methanaminium chloride, an analogue of butenafine from tertiary-butyl benzyl derivatives, (II) to compare the solvent actions of Tetrahydrofuran (THF), acetonitrile, methanol and 1,2-dichloroethane (DCE), and the reducing efficiencies of NaBH₄ and sodium triacetoxyborohydride (STAB) during the synthesis.

Study Design: The study involved laboratory experiments leading to the synthesis of the target compound by varying the non-aqueous solvents used, the reducing agent and the temperature of the operations. Silica chloride catalyst was used to speed up the reaction in one of the syntheses and in each synthesis, Thin Layer Chromatography was used to monitor the progress of the reaction. The time taken by each reaction and the yield were used as the basis for determining the solvent action and the reducing efficiency.

Place and Duration of Study: M.Sc. Access controlled Teaching Laboratory, School of Chemistry, Newcastle University, New castle upon Tyne, United Kingdom from June to August 2012.

Methodology: Reductive amination was carried out by reacting 4-tert-butylbenzaldehyde and 4-tert-butylbenzylamine, using the direct and then the indirect approaches. This was followed by methylation using the Eschweiler-Clarke reaction in each of the two approaches. The time taken by each reaction was monitored and the product of each approach was characterised by EIS-MS, ¹H NMR, ¹³C NMR and FTIR.

Results: 1,2-dichloroethane gave the best solvent action at 40°C (Yield: 75%) and NaBH₄gave the best-reducing action with silica chloride catalyst at 25°C (Yield: 50%). At the end of each synthesis, in all obtained products,¹H NMR spectrum gave a single peak of 18 hydrogen atoms at 1.3 -1.5 ppm for the existence of 6 methyl groups in the two tertiary-butyl substituents, the ¹³C NMR spectrum also showed a peak at 31-32 ppm for the six methyl carbon atoms in the two tertiary-butyl substituents, the FTIR spectrum showed a strong band at 2460 cm^-1 for the presence of a tertiary ammonium ion and finally the EIS-MS gave a mass to charge ratio of 324.2693 as a confirmation of the relative molecular mass of the compound.

Conclusion: The target compound can be synthesised by both direct and the indirect approaches of reductive amination in any of the solvents tested with/without a catalyst at room or elevated temperature using NaBH₄ or STAB as a reducing agent but the best solvent action can be achieved with DCE at 40°C and the best-reducing action can be achieved with NaBH₄ in the presence of silica chloride.

Synthesis of Benzothiazoyl Salicylate Moieties

Diepreye Ere — 2019-12-10

Aminosalicylates are derivatives of the highly functionalized compound aminosalicylic acid. Benzothiazoyl salicylates were obtained in this work from the highly functionalized aminosalicylic acid by reacting ammonium thioureas as a nucleophile to aminosalicylates that were derived from aminosalicylic acid and bromine was used as the cyclising agent. Results obtained indicated that it was the brominated cyclised product that was formed.

Development Studies of Biodegradable Pressure Sensitive Adhesives and Fiber Reinforced Polyester Composites from Castor Oil

J. Shakina — 2019-12-10

The potential use of castor oil in preparation of novel biodegradable polymeric pressure sensitive adhesives and fiber reinforced polyester composites was investigated. A biodegradable oligomeric fumarated resin was prepared by the insitu hydroxylation of castor oil followed by maleation under controlled reaction conditions. Then two varieties of biodegradable pressure sensitive adhesives (PSAs) were prepared by further reacting the resin with co-monomers vinyl acetate and methyl acrylate. The PSAs were characterized for biological and physicochemical properties; namely thermal stability, transparency, chemical resistance, biodegradability, and tensile strength. Fiber reinforced polyester composites were prepared by free radical polymerization of oligomeric fumarated resin mixed with different propositions of Jute and Sisal fiber. The composites were then analyzed for physicochemical by AT-IR, SEM, TGA and DSC techniques, The results indicate that castor oil-based PSA films and tapes have applications in various fields including flexible electronics and medical devices because of their thermal stability, transparency, chemical resistance, and potential biodegradability from triglycerides. Mechanical characterization of the composites was also done and the results positively indicated the Sisal and Jute fibers have the potential to be used as substitutes for synthetic fibers in green composites. The composites can be used for the fabrication of eco-friendly materials.

Densities, Viscosities and Ultrasonic Studies of Binary Liquid Mixture of Ethylamine and Benzyl Alcohol at Different Temperatures

Chandra Mohan Saxena — 2019-12-10

Ultrasonic studies, densities and viscosities of binary liquid mixture of ethylamine and benzyl alcohol have been measured at different temperatures at 30ºC, 35ºC and 40ºC. The experimental value of speed of sound (u), isentropic compressibility (βs), intermolecular free length (Lf), viscosity (η), available volume (Va), molar volume (Vm) and Nissan’s parameter (d) have been calculated of ethyl amine and benzyl alcohol in the pure state as well as mixture over whole composition range were measured at 30ºC, 35ºC and 40ºC. These properties also provide important information about molecular packing, molecular motion and various types of intermolecular interactions and their strength, influenced by the size shape and chemical nature of component molecules.

The Effect of Sterculia setigera Del. Bark Extract on the Flammability of Flexible Polyurethane Foam

Baffa Abubakar — 2019-12-10

Fire retardant properties of the bark extract of Sterculia setigera on flexible polyurethane foam were investigated. The foam was treated with different concentrations of the extract and its flammability characteristics were compared with that of untreated sample. The result indicated increase in Ignition Time and Percentage Char with the increase in concentration of the incorporated extract while the Flame Propagation and After-Glow Time of the treated foam decreased with increase in concentration of the extract in the foam. The result revealed that the extract can significantly reduce the flammability of flexible polyurethane foam and serve to substantiate the local use of the plant in fire prevention by Hausa tribe.

Kinetic Spectrophotmetric Method for Quantitation of Rizatriptan Benzoate in Pharmaceutical Formulations

S. Malini — 2019-12-10

A simple, sensitive and accurate kinetic spectrophotometric method for the determination of Rizatriptan Benzoate in pure and dosage form is described. The method is based on spectrophotometrically monitored oxidation of the drug by a known excess of Chloramine-B in HCl medium using initial rate, fixed time and variable time method in HCl medium. The oxidized product exhibits a maximum absorption at 490nm. The apparent molar absorptivity and Sandell’s sensitivity values are in the range 2.97 x 10⁴to 0.0198 respectively. The proposed method has been successfully applied to the determination of RTB in commercial pharmaceutical formulations. Statistical comparison of the results with well-established reported method shows agreement in terms of precision and accuracy.

Comparative Study of CBS-Q Calculated and Experimental pKa Values for Fluoro-acetoxy Derivative

Mustafa Lawar — 2019-12-10

The pKa values were calculated for some acetoxy group molecules using CBS-Q method which is one of the Complete Basis Set methods to find accurate energies. The acetoxy group molecules were also planned by Quantitative Structure Activity Relationship (QSAR) to study their effect on paraoxonase1 activity.

The results of this study showed a strong relationship, (R²=0.99) between the calculated and experimental pka, also showed correlations between the activity of the enzyme and some of the studied descriptors. Moreover, the results of the study revealed that by using the SPSS program, there is a correlation between LUMO, Softness, Nucleofugality and Electrofugality as dependent variables and Cal. pKa as an independent variable.