Liquid phase esterification of carboxylic acids with alcohols is an important organic synthesis process in the
petrochemical and fine chemical industries. These reactions required mineral acid catalysts, which are corrosive
and difficult to be separated from the reaction mixture. Therefore, the use of solid acid catalysts is economically
viable, reusable, and environmentally amicable. In this study, sugarcane bagasse ash (SCBA) was impregnated
with 1–10 wt% of sulfuric acid (H2SO4) or perchloric acid (HClO4) for the liquid-phase esterification of acetic
acid with n-amyl, benzyl, and n-butyl alcohols under various reaction conditions. The catalysts were characterized using X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier-transform infrared (FTIR), N2 sorption, and scanning electron microscopy (SEM). Their acidities were measured through the dehydration of isopropyl alcohol and pyridine adsorption FTIR. The effects of the acid activation of SCBA on its texture properties (such as surface area and the nature of the surface functional groups), acidity, and catalytic activity were studied in detail. FTIR of the pre-saturated catalysts with pyridine reflected the presence of Brønsted and Lewis acid sites. The concentrations of the acid sites were improved by increasing the percentages of acid loading. All the catalysts showed high catalytic activity with 100% selectivity to ester formation. The catalyst pretreated with H2SO4 showed the higher ester yields compared to that of treated with HClO4. The optimum reaction conditions were a reaction time of 2 h, an alcohol-to-acid molar ratio of 1:3, and catalyst loading of 0.5 g. The highest yields of namyl acetate, benzyl acetate, and n-butyl acetate of 98, 90.8, and 70.5%, respectively, were achieved over the SCBA pretreated with 10 wt% H2SO4 catalyst. The high catalytic performance of this catalyst is due to the high surface acidity generated by the inductive effect of the S– –O bond.
 

A [ZrO2?BTB]C nanocomposite was synthesized and prepared as a thin film
using the sol–gel spin coating method. Different characterization techniques for
[ZrO2?BTB]C like FTIR, UV–Vis, and optical properties have been used. The
resulted XRD and SEM data have been employed to study interface composites.
The optimization was performed using DFT by DMol3 and CASTEP program.
The chemical structure was confirmed by spectroscopic and structural properties for [ZrO2?BTB]C. XRD results showed the same crystal structure. Combined
between experimental and TDD-DFT data, the average crystallite size and
composite interface are 12.36 nm and orthorhombic symmetry (a = 7.38(5);
b = 18.178(6); c = 26.10(3) A˚ and a = b = g = 90) with space group (P61) for
[ZrO2?BTB]C, respectively, while those computed by DFT are 2.897 eV and
2.492 eV for as-isolated crystals of [BTB]TF and [ZrO2?BTB]C, respectively. Both
[BTB]TF and [ZrO2?BTB]C thin films have direct allowed transitions. In addition, the optoelectrical parameters have been calculated for [BTB]TF and
[ZrO2?BTB]C films such as refractive index, extinction coefficient, dielectric
constant, and optical conductivity. The simulated values obtained by CATSTEP
for the optical parameters of [ZrO2?BTB]C are in good agreement with the
experimental values. PL technique analyses indicated two emission peaks
appeared at 357 nm, and 497 nm for [ZrO2?BTB]C, whereas three emission peaks
appeared at 335 nm, 383 nm, and 477 nm for [BTB]TF. The [ZrO2?BTB]C presents
a good candidate for optoelectronics and solar cell applications.
 

Metallic copper nanoparticle (Cu NP)-doped 1D hydroxyapatite was synthesized using a simple chemical reduction
method. To describe the structure and composition of the Cu/HAP nanocomposites, physicochemical techniques such as X-ray
diffraction, Fourier transform infrared spectroscopy, inductively coupled plasma, N2 adsorption-desorption, X-ray photoelectron
spectroscopy, and high-resolution transmission electron microscopy were used. The TEM scan of the Cu/HAP nanocomposite
revealed a rod-like shape with 308 nm length and 117 nm width on average. The catalytic activity of Cu/HAP nanocomposites for
the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of NaBH4 has been thoroughly investigated. The
0.7% Cu/HAP nanocomposite was shown to have superior catalytic activity than the other nanocomposites, converting 4-NP to 4-
AP in ∼1 min with good recyclability. Moreover, this nanocomposite showed excellent catalytic performance in the organic dye
reduction such as Congo red and acriflavine hydrochloride dyes. The high dispersion of Cu NPs on HAP support, the high specific
surface area, and the small Cu particles contributed to its remarkable catalytic performance.
 

The oxidation of 3′,3″-dibromothymolsulfonphthalein (DBTS) in neutral medium by potassium permanganate multiequivalent oxidant has been studied spectrophotometrically. Pseudo-first-order plots showed inverted S-shape throughout the entire
course of the reaction. The initial rates were found to be relatively fast in the early stages, followed by a decrease in the oxidation
rates over longer time periods in the slow stage. Under pseudo-first-order conditions where [DBTS] ≫ 10 [MnO4-], the
experimental results showed a first-order dependence in [MnO4-] and fractional-first-order kinetics in the [DBTS] concentration.
The formation of 1:1 coordination intermediate complex prior to the rate-determining step was revealed kinetically. In addition, the
intermediate species involving complexes of Mn(V) coordination has been detected. The oxidation product of DBTS was identified
by Fourier transform infrared spectroscopy, ultraviolet-visible spectrophotometry, and gas chromatography-mass analysis. The
obtained results indicated the formation of 2-bromo-6-isopropyl-3-methyl-cyclohexa-2,5-dienone as a derivative oxidation of DBTS
 

Oxidation is the preferred method that used for the removal of colored toxic dyes from wastewater. Various oxidizing agents such as permanganate ion, chromate ion, ferricyanide ion have been studied kinetically to remove these colored dyes from water. In compared to the other oxidizing agents, potassium
permanganate is inexpensive, water-soluble, eco-friendly oxidant, and it can be used in acid, alkaline,
and neutral conditions. In addition, it has been widely used for treatment of pollutants in drinking water and waste-water applications for over 50 years. In this work, the kinetics of bromothymol blue (BTB)
oxidation by KMnO4 were investigated using a conventional spectrophotometer in neutral solutions. The
oxidation reaction rates were accelerated to notable rates by using of Ru (III) as a homogeneous catalyst. The pseudo-1st - order model showed a 1st order in terms of both reactant’s concentration, and
2nd overall reaction. The kinetic data indicated the founding of a 1:1 intermediate species with the intervention of free radicals into the reaction mechanism. At the reaction conditions of [BTB]=1 × 10–5,
[MnO4–] = 4 × 10–4 mol dm–3, and 25 °C, the pseudo-first order rate constant values were calculated to be 1.13×10–4 s–1 without Ru (III) and 1.66×10–4 using Ru(III) as a catalyst (4 × 10–4 mol
dm–3). Considering the kinetic results, a putative the mechanism of the reaction in the stated redox
reaction is postulated and examined. Activation parameters without and with using of Ru (III) were
calculated.
 

A novel ZrO2-acriflavine nanocomposite thin film [ZrO2+ACF]C complex as a powder form was synthesized and prepared as a thin film using the Sol-Gel spin coating tool. Various methods of characterization have been utilized, such as FTIR, UV–Vis, SEM and optical properties. Optimization by DMol3 and
CASTEP was implemented utilizing DFT. The chemical structure for [ZrO2+ACF]C as nanocomposite family
drugs was confirmed by its spectroscopic and structural properties. The average crystallite size [ZrO2+
ACF]C is 59.76 nm. Furthermore. The optical energy band gap calculated by Tauc’s equation is 2.291 eV
and 2.117 eV for [ACF]TF and [ZrO2+ACF]C films, respectively. Whereas the calculated by DFT (DMol3) are
2.213 eV and 1.633 eV for [ACF]TF and [ZrO2+ACF]C, respectively. In addition, the optoelectrical parameters have been computed for [ACF]TF and [ZrO2+ACF]C films. The simulated values obtained by CASTEP in
DFT for the optical parameters of [ZrO2+ACF]C are in good agreement with the experimental values. The
[ZrO2+ACF]C presents a good candidate for optoelectronics and solar cell applications.
 

Dimethylamino-2H-5-dihydropyrane-6-methyl-4-one (DADHP) is a novel antibacterial pyrones derivatives and
potential pharmaceutical that was quantitatively synthesized by oxidizing azithromycin (AZ) antibiotic with
potassium permanganate in an alkaline medium (pH > 12). The oxidation reaction was kinetically studied using
spectrophotometric technique at ionic strength equal to 0.02 mol dm- 3. The redox reaction was discovered to
have two separate stages that could be measured. The first stage was relatively fast and corresponding to the
formation of coordination intermediate complexes involving blue hypomanganate (V) and/or green manganate
(VI) transient species. Variable parameters like as the concentration of permanganate ion and AZ substrate, as
well as pH and ionic strength, have been studied to see how they affect oxidation rates. The experimental results
showed a first-order dependency in [MnO4-] and fractional first-order kinetics in each of [AZ] and alkali concentration under pseudo-first-order reaction conditions of [AZ] ≫ 10 [MnO4-]. The oxidation process was basecatalyzed, and the oxidation rates increased as the alkali concentration increased. The product was confirmed by Fourier Transform Infrared spectroscopy (FTIR), elemental analysis, condensation tests with 2,4-dinitrophenyl haydrazine and hydroxyl amine, and GC-Mass. The oxidation product obtained can be employed as interesting class of organic compounds with diverse chemical and pharmacological applications.