Effect of solvent type on the formation rate of benzyl cation intermediate in acidolysis of lignin

The purpose of this study was to examine how the type of solvent among aqueous 1,4-dioxane, tetrahydrofuran, ethanol, iso-propyl alcohol, or ethylene glycol and its content (mol%) affect the formation rate of benzyl cation intermediate (BC) in the acidolysis of lignin, using a simple model compound, 1,2-dimethoxy-4-methoxymethylbenzene. Because the BC forms from the model compound via two steps, i.e., protonation of the benzyl methoxymethyl group as the pre-equilibrium step and liberation of the methanol as the rate-determining step, the observed variation of the formation rate with type of solvent and solvent content originates from the effects on both steps undistinguishably. The formation rate of BC decreased with increasing mol% of any of the organic solvents for a range of relatively low mol%, but increased with it for relatively high mol%. The formation rate varied more in the ether than in the alcohol systems. These results seem to be regulated by the effect of changing the mol% on the pre-equilibrium step, i.e., on the proton activity, rather than on the rate-determining step. Two reaction products, 4-alkoxymethyl-1,2-dimethoxybenzene and 4-hydroxymethyl-1,2-dimethoxybenzene, exclusively formed in the aqueous alcohol systems. The former compound was confirmed to be thermodynamically more stable and kinetically the more favorable product.

Effect of Solvent Conditions in Process of Extraction of Pectin from Banana Peels for the Adsorption of Fe Metal in Groundwater at UPN Veteran Yogyakarta

Iron (Fe) is one of the compounds contained in heavy metals which is very dangerous for the survival of living things when in the environment around the residence that has exceeded the threshold. Fe ions can cause turbidity, corrosion, and other impacts. Iron (Fe) is a transition metal and has the atomic number 26. The oxidation numbers of Fe are +3 and +2. Fe is an essential metal for the body which in high doses is toxic. Given the various dangers caused by exposure to Fe metal, it is necessary to treat Fe metal contained in groundwater. One of the most widely used heavy metal processing methods is the adsorption process. In previous studies, many adsorption processes used activated carbon from various materials as adsorbents. In this study, pectin was extracted from banana peels with hydrochloric acid as a solvent at various temperatures and concentrations. The optimum conditions were at 80oC and a concentration of 0.35 N. The pectin obtained was 2.3171 grams.

Synthesis of ZIF-67- Effect of solvent on the structure

In the present paper, ZIF-67 material was synthesized from cobalt (II) nitrate hexahydrate and 2-methyl imidazole in three different solvents (methanol, ethanol and acetone) at room temperature. The obtained samples were characterized using XRD, SEM, FTIR, TGA and nitrogen adsorption/desorption measurements. The results show that the synthesized ZIF-67 materials had a high purity, nano-size, and uniformity with the sharp dodecahedrons structure of ZIF-67. Solvents had an influence on the size and nature of the ZIF-67 crystal. The average crystalline size of the nanoparticles calculated by Scherrer equation were 64 nm for sample in acetone solvent, 128 nm for sample in ethanol solvent and 132 nm for sample in methanol solvent. The obtained samples had high thermal stability ( 320 °C). The ZIF-67 material with ethanol solvent had a high specific surface area (SBET) of 1506 m2/g. The synthesized samples exhibited better adsorption capacity of methyl oranges than that of rhodamine B.

Effect of Solvent on the Hydrodynamic Properties of Collagen

In this study, the effect of solvent on the hydrodynamic properties of collagen extracted from tail tendons of young rats was researched. Collagen was dissolved in various aqueous carboxylic acid solutions, including acetic acid (AA), acetic acid with the addition of sodium chloride (AA/NaCl), formic acid (FA), lactic acid (LA), citric acid (CA), and also citrate buffer at pH = 3.7 (CB). The properties of collagen solutions at a concentration of 0.45 mg/mL were characterized based on the viscometric method. The reduced viscosity, intrinsic viscosity, and Huggins coefficient of collagen solutions and effect of solvent, temperature, and UV irradiation on these properties were investigated. Collagen solutions in acetic acid, acetic acid/NaCl, and citrate buffer were irradiated with UV light up to 1 h, and the viscosity of collagen solutions was measured. It was found that the organic acids used as solvent affected viscosity behavior, denaturation temperature, and stability of collagen solutions. The lowest values of studied parameters were obtained for the collagen solutions in acetic acid with the addition of sodium chloride. Thus, the effect of various aqueous carboxylic acid solutions on collagen solutions properties and denaturation temperature can also be affected by the sodium chloride addition. The results of this research can be crucial for the preparation of collagen solutions for both cosmetic and biomedical applications.