Crystalline Boric Acid Research Articles

Production of crystalline boric acid and sodium citrate from borax decahydrate

Tincal, colemanite and ulexite are the most commercially significant borate minerals. The commercial production of boric acid from these minerals is based on a mineral–inorganic acid reaction. In this study, crystalline boric acid (H3BO3) was produced from borax decahydrate using an organic acid, and trisodium citrate dihydrate (Na3C6H5O7·2H2O) was also obtained via crystallization from the residual mother liquor. The products were identified by X-ray powder diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric and differential thermal analysis (TG-DTA). The impurities in the boric acid products were determined by inductively coupled plasma spectroscopy (ICP-OES), ion chromatography, and total organic carbon (TOC) analysis. Boric acid was separated from reaction mixture via batch crystallization and the recovery yield was achieved 69%. The purity value of the crystals was increased from 97.5% to 99.9% by recrystallization. The proposed production method may be more attractive than the current commercial processes because it deals with green and sustainable process, preventing a high consumption of inorganic acids and generation of solid waste. Moreover, the trisodium citrate obtained as a by-product is a high value-added chemical.

Effect of boron doping on optical properties of sol–gel based nanostructured zinc oxide films on glass

Boron doped zinc oxide thin films (∼80 nm) were deposited onto pure silica glass by sol–gel dip coating technique from the precursor sol/solution of 4.0 wt.% equivalent oxide content. The boron concentration was varied from 0 to 2 at.% w.r.t. Zn using crystalline boric acid. The nanostructured feature of the films was visualized by FESEM images and the largest cluster size of ZnO was found in 1 at.% boron doped film (B1ZO). The presence of mixed crystal phases with hexagonal as major phase was identified from XRD reflections of the films. Particle size, optical band gap, visible specular reflection, room temperature photoluminescence (PL) emissions (3.24–2.28 eV), infra-red (IR) and Raman active longitudinal optical (LO) phonon vibration were found to be dependent on dopant concentration. For the first time, we report the room temperature fine structured PL emissions as phonon replicas originated from the LO phonon (both IR and Raman active) in 1 at.% boron doped zinc oxide film.

A Metal Cutting Approach to Investigate the Tribological Properties of Nano Crystalline Boric Acid and the Effect of its Carrying Medium

The pin on disc (POD) tests revealed an inverse relationship between coefficient of friction and the particle size of boric acid. So, as the properties of materials are changing with respect to its spatial dimension, the tribological performance of solid lubricant in the metal cutting is a matter of research. The present work aims at investigating the effect of variation of particle size of boric acid in the nano level in the machining of hardened steel. Canola oil and SAE 40 oil are tested as the carrying media for nano crystalline boric acid. In both cases, all the machining parameters viz. cutting forces, tool temperatures and surface roughness increased with the decrease of the particle size in nano level. The effect of carrying medium is also targeted and SAE 40 oil has been found as the best.

Influence of nano-level variation of solid lubricant particle size in the machining of AISI 1040 steel

Significant advances have been made in understanding the behaviour of engineering materials when machining at higher cutting conditions from practical and theoretical standpoints. Nano-integrated manufacturing is a subject of immense interest for various sustainable engineered systems. Metal removal processes involves generation of high cutting forces and temperatures. Usage of proper lubricant is an important aspect to reduce forces and temperatures and as a whole to improve total cutting phenomena. The present investigation analyses a green, petroleum-free lubricant that is produced by mixing two environmentally benign components – canola oil and nano crystalline boric acid. To study the influence of variation of nano-level boric acid particle size and its weight percentage on the performance of proposed green particulate fluid lubricant (GPFL), various turning tests were conducted on AISI 1040 steel using tungsten carbide inserts. Variations in cutting forces, tool temperatures and surface roughness are studied. The experimental results reveal that increase of cutting forces as well as the tool temperatures with the decrease in the boric acid particle size. The surface quality of the machined surface is reduced as the solid lubricant particle size is reduced in the nano-level.

Lubrication Properties of Vegetable Oils Combined with Boric Acid and Determination of Their Effects on Wear

Lubrication is essential in increasing a mechanical component's service duration and minimizing wear. Though synthetic and petrol-based oils are generally used in lubricants today, natural oils which are environment-friendly, biologically decomposable, and whose waste does not give harm to the environment have also begun to be used as lubricants recently thanks to an increasing awareness of the environment. In the present study, vegetable-oil based canola oil and boric acid were combined and their wear performance was investigated. In the experiments, wear performances of commercial mineral oil, pure canola oil, and a combination of canola oil and boric acid were compared on a pin-on-disc test apparatus at a constant speed of 1.5 ms−1 and under various weights of 60, 120, and 180 N. The layer structure of crystalline boric acid particles can slide over each other with relative ease and can reduce friction and wear.

Effects of liquid insecticide baits on Argentine ants in California's coastal vineyards

Liquid ant baits were evaluated for control of Argentine ants, Linepithema humile (Mayr), and associated mealybug pests ( Pseudococcus species) in commercial vineyards. In all trials, liquid baits were an insecticide dissolved in 25% sugar water. In 2000, two liquid baits—crystalline boric acid and imidacloprid—were deployed in ground-based dispensers at rates of 85 (site 1) and 175 (site 2) dispensers per ha. Season-long ant densities were significantly lower than a no-insecticide control in only the boric acid treatments, and at only 1 of 2 sites. In 2001, four liquid baits—imidacloprid, fipronil, and thiamethoxam, each mixed at 0.0001% (A.I.)—were delivered in ground-based dispensers at a rate of 120 dispensers per ha. There was no treatment impact on ant or mealybug densities. In 2002, a liquid bait—thiamethoxam, mixed at 0.0001% (A.I.)—was delivered in ground-based (site 1) and canopy-based (site 2 and 3) dispensers that were recharged every 2 wk and cleaned every 4 wk, and deployed at rates of 160 (sites 1 and 2) and 620 (site 3) dispensers per ha. There was a significant reduction of season-long ant densities in liquid bait treatments at all sites, and of mealybug densities at 2 of 3 sites; crop damage was significantly lower in the liquid bait treatment at all sites. The results are discussed with respect to the methodologies used to deploy liquid baits and the development of a viable commercial program.

Direct production of crystalline boric acid through heterogeneous reaction of solid borax with propionic acid: Operation and simulation

The production of boric acid through reaction of borax crystals with propionic acid was investigated in batch mode. It was found that the product boric acid precipitates on the solid borax reactant. An increase in the coefficient of variation of feed crystals resulted in an increase in the time of completion of the reaction. A sharp interface model with variable bulk fluid concentration of liquid reactant was developed for simulation of the process. The analytical solution of the series of rate equations invol ving liquid film, solid boric acid layer and chemical reaction resistances was obtained, and a new method for simultaneous determination of kinetic parameters was established. The chemical reaction and diffusion through the solid layer of boric acid were the rate controlling mechanisms. A numerical algorithm was also developed for predicting the fractional conversion of multisize borax crystals using the mono size kinetic parameters determined according to the proposed analytical method.

Production of Crystalline Boric Acid through the Reaction of Colemanite Particles with Propionic Acid

AbstractA new process for boric acid production is developed. In this process the crystalline boric acid particles are directly produced in a one‐stage crystallizer through the reaction of colemanite particles with propionic acid. Each porous colemanite particle is comprised of spherical solid grains. It is found that the solid boric acid produced precipitates on the unreacted core of the grains. The maximum overall conversion of colemanite particles can be increased to 97% if the propionic acid concentration, stirrer speed, concentration, stirrer speed, colemanite mean particle size and temperature are set at 16 kmol/m3, 20 Hz, 462 μ and 295 K, respectively. Therefore it is possible to use this process as an alternative for boric acid production, also having a useful side product. A particle‐grain model is successfully used for process simulation.

Use of solid boric acid as an ammonia absorbent in the determination of nitrogen

An inexpensive trap-de-mister assembly utilising solid crystalline boric acid as an ammonia absorbent was developed to replace the specialised trap-condenser-impinger apparatus normally used in Kjeldahl-type distillations. The boric acid is subsequently dissolved in water and a final determination of the ammonium ion is made either by acidimetric titration, a conductance measurement or spectrophotometric measurement after the addition of Nessler's reagent. The apparatus fits into the neck of a calibrated flask during the distillation and is itself constructed from disposable plastic pipette tips, glass-wool and rubber tubing. Both the high surface area and the tortuosity of the paths through the randomly packed bed of crystals makes solid boric acid an efficient ammonia absorbent. The system is useful for small-scale separations only because, when the volume of solution from which the ammonia is distilled exceeds 25 ml, the acid crystals become saturated with water and begin to dissolve before all of the ammonia is trapped.

The Raman spectrum of boric acid

The Raman spectrum of crystalline boric acid is recorded using mercuryλ2537 excitation. Fifteen Raman lines, three of them belonging to the lattice spectrum, are reported. Satisfactory assignments of all the observed Raman frequencies are made using the available X-ray crystal structure data. From the presence of a new high frequency Raman band at about 3420 cm.−1 it is suggested that there might be a small number of long, weak O-H....O hydrogen bonds in the crystal, in addition to the hydrogen bonds of moderate strength reported from X-ray diffraction data.

Heats of Combustion and Formation of Trimethylborane, Triethylborane, and Tri-n-butylborane.

The heats of combustion at 25 °C of trimethylborane (liquid), triethylborane (liquid), and tri-n-butylborane (liquid), to form crystalline boric acid, liquid water, and gaseous carbon dioxide have been determined to be −2989.4 ±22.4 kj/mole (−714.48 ±5.36 kcal/mole), −4975.6 ±15.1 kj/mole (−1189.2 ±3.6 kcal/mole), and −8901.0 ±10.2 kj/mole (−2127.4 ±2.4 kcal/mole), respectively. These data, combined with the heats of formation of boric acid, carbon dioxide, and water give −34.79 ±5.40, −47.2 ±3.7, and −83.2 ±2.5 kcal/mole at 25 °C for the standard heats of formation of trimethylborane, triethylborane, and tri-n-butylborane, respectively. The data of other investigators are discussed briefly.