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Development of a Novel Nanocomposite Coating for Tribological Applications
Published in Catalin I. Pruncu, Jamal Zbitou, Advanced Manufacturing Methods, 2023
Arti Yadav, M. Muthukumar, M. S. Bobji
In near-neutral solutions of boric acid, ammonium borate, ammonium tartrate or ammonium tetraborate, the rate of water-splitting reaction (Eq. 9.4) is slow. As the compact oxide layer grows, the aluminium, oxygen and hydroxyl ions have to transit through the existing oxide layer. The currently held view is that all the three ions move through the oxide [26, 27]. The movement of these ions is governed by a high field conduction equation, j=Aexp(BE)
Crystallization and Structural Linkages of COFs
Published in Atsushi Nagai, Covalent Organic Frameworks, 2019
There have been many studies on reactions between boric acid and diols in connection with changes in conductivity, acidity, and rotatory polarization [25]. Hermans pointed out that the changes in these physical properties are due to the formation of a spiroborate complex that is produced from those reactions in a solution [26]. The first isolation of the spiroborate complex was performed by Böeseken and coworkers, who synthesized potassium biscatechol spiroborate from the reaction of catechol with potassium borate in water (Eq. 2.3) [25]. On the other hand, spiroborates are ionic derivatives of boronic acid, which have been reported to exhibit high resistance toward hydrolysis and stability in water, methanol, and under basic conditions [27, 28]. A spiroborate linkage can be formed readily through the condensation of polyols with alkali tetraborate [29, 30–32] or boric acid [33–35] or through the transesterification between borate and polyols [36] in a thermodynamic manner.
Recent Advances in Boron-Based Flame Retardants
Published in Yuan Hu, Xin Wang, Flame Retardant Polymeric Materials, 2019
Several guanidinium borates have been reported in the literature. For example, guanidinium tetraborate [C(NH2)3]2O.2B2O3.4H2O] can be prepared by reacting guanidinium carbonate with boric acid in hot water or by reacting guanidinium chloride with borax in cold water (Weakley 1985). Guanidium borate or its precursors (BA plus guanidine) are mostly used for flame retardant cellulosic product. For example, Sanyo in Japan reported the combination of calcium imidosulfonic acid and guanidinium borate or guanidinium sulfamate provides excellent flame retardancy in cellulosic materials (Yoshiyuki and Yashushi 1997). A combination of guanidium borate and imidazolium borate was reported for treating cotton fabrics to raise LOI from 18.8% to 24.6% and 25.8%, respectively, at 5 wt% loading (Dogan 2014).
Reclamation of mineral acids from various waste streams using solvent extraction technique: a review
Published in Geosystem Engineering, 2023
Muhammad Ahmad Muhsan, Ameer Fawad Zahoor
Fan et al. investigated extraction of boron with 2-ethyl-1, 3-hexadiol (EHD) diluted in sulphonated kerosene (SK) from underground brine. The outcomes revealed that effective extraction of boron could be achieved by five stage counter extraction under optimum conditions such as extractant concentration (EHD 30%+ SK 70% v/v), organic to aqueous ratio (O/A) 1:2 and pH in between 2 to 3. Approximately 98.5% boric acid was extracted out under optimum conditions whereas initial concentration of boron oxide in aqueous feed was 17.48 g/L. Back extraction (stripping) of loaded boric acid from extractant was achieved with 1 M sodium hydroxide (NaOH) while kept organic to aqueous ratio (O/A) 1:1. About 97% boric acid was recovered by five stage counter current back extraction. Additionally, small amount of (tetraborate pentahydrate) was recovered by evaporation of extracted liquor of stripping but 88% boric acid recovered when extracted liquor under go to acidification about pH less than 2.5 before evaporation. The exact mechanism of extraction between boric acid and EHD revealed that extraction of boric acid related with esterification between hydroxyl of EHD and OH get from boric acid (H3BO3) with stoichiometric chemistry of 1:1 and produce six members stable ring of boric acid ester along elimination of two water molecule (Fan et al., 2018)
Characterization of lime mortar additivated with crystallization modifiers
Published in International Journal of Architectural Heritage, 2018
Sanne J.C. Granneman, Barbara Lubelli, Rob P.J. Van Hees
Two modifiers have been selected to be mixed in the mortar: sodium ferrocyanide (sodium hexacyanoferrate(II)-10-hydrate, Riedel-deHaën, puriss.) and borax (sodium tetraborate decahydrate, Sigma-Aldrich, puriss.). The first is a crystallization inhibitor and habit modifier of sodium chloride crystallization (Van Damme Van Weele 1965), the second is a modifier of sodium sulfate crystallization (Granneman et al. 2017; Ruiz-Agudo and Rodriguez-Navarro 2010). The effect of the carbonation process of the mortar on the effectiveness of the modifier was only studied for borax and sodium sulfate, as this was already studied for ferrocyanide and sodium chloride in previous research (Lubelli et al. 2010). In all other experiments both modifiers are considered.
Bio-oil and bio-char from lactuca scariola: significance of catalyst and temperature for assessing yield and quality of pyrolysis
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
When the values of liquid, solid, gas, and conversion rates in Figure 2. are examined; it is seen that not all catalysts have the same effect. It has been observed that catalysts have a synergetic effect with the temperature compared to the non-catalyzed experiment. In the experiments carried out at 350 °C, except boric acid and di-sodium tetraborate pentahydrate catalysts, other catalysts showed less effect than non-catalyst trials in the liquid product yields. Although the difference between the experiments at 450 and 550 C was very low, all the catalysts were more effective than non-catalyst. In the liquid product yield values, the highest yield was reached at 450 °C in all experiments, except for ZnCl2 catalyst; the highest liquid product yields were determined as catalyst free (28.65%), H3Bo3 (31.79%), NaOH (28.69%), Na2B4O710H2O (30.43%), K2CO3 (29.74) and ZnCl2 (33.97%) at 550 °C. ZnCl2 is Lewis acid catalyst commonly used in pyrolysis of biomass. This catalyst catalyzes the breakage of the C-C and C-O bonds; it does this by reactions such as dehydration, depolymerization, and ring-opening. By the addition of ZnCl2, the breakdown of cellulose and hemicellulose polymers decreases char, and the gas formation increases. Also, with the catalyst, the furfural yield increases significantly. The catalyst supports both primary and secondary reactions in the pyrolysis process, causing a higher proportion of furfural formation with the dehydration of the pentosyl, glucosyl residues and anhydrosugars (DiBlasi et al. 2015; Wang et al., 2017).