Synthesis of Enriched 10B Boric Acid of Nuclear Grade

An economic and effective method of preparing enriched 10B boric acid was established by chemical reactionof enriched 10BF3 and CaCO3. A process of boron trifluoride reacting with water was investigated under certainconditions. Calcium carbonate was selected to counteract hydrofluoric acid followed on. Some key operation factorswere investigated, such as temperature, reaction time and the ratio of CaCO3 to 10BF3. The results showed that the yieldof enriched 10B boric acid could reach 97. 2% and the purity was up to 94. 1% under the following conditions： the temperaturewas 50-60,℃, the reaction time was 28 h and the ratio of CaCO3 to 10BF3 was 4. In addition, after recrystallizationand titration analysis, the purity of the product could reach over 99. 2% from 94.1%.

EFFECT OF BORIC ACID ON THE EXTRACTION OF BASTNASITE LEACHING LIQUOR BY CYANEX 923

The effect of boric acid on the extraction of bastnasite leaching liquor by Cyanex 923 was studied. Boric acid wasn’t extracted alone by Cyanex 923 and didn’t influence the cerium(IV) extraction. But it can enhance the extraction of hydrofluoric acid evidently and came into organic phase in form of (HF)(H3BO3).(Cyanex 923).

Influence of Boric Acid and Sucrose on the Germination and Growth of Areca Pollen

This study investigates the effect of boric acid and sucrose on the germination and growth of Areca catechu L (areca palm). Using areca pollen from Hainan, China, this study determines the influence of culture media with different concentrations of boric acid and sucrose on the germination and growth of areca pollen. Results show that the germination and growth of the pollen tube growth are highest under a boric acid concentration of 0.4 g/L to 0.6 g/L. The germination rate of areca pollen is highest in solid medium with a sucrose concentration of 40 g/L. The optimum culture medium for developing areca pollen comprises 5 g/L agar, 0.4 g/L to 0.6 g/L boric acid, 40 g/L sucrose, and water. Furthermore, areca pollen grows most rapidly approximately 1.5 h after in vitro cultivation at normal temperature, and growth stabilizes at approximately 3 h. The principle that governs the development of areca pollen is also discussed.

On the Role of Boric Acid in the Copper-Tin Alloy Bath

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Efficient one-pot synthesis of 14-substituted-14H-dibenzo[a,j]xanthenes using boric acid under solvent-free conditions

Boric acid efficiently catalysed the one-pot reaction of alkyl or aryl aldehydes with 2-naphthol to afford the corresponding 14- alkyl-or aryl-14H-dibenzo[a,j]xanthenes in good yields under solvent-free conditions.

Boric acid reduces axonal and myelin damage in experimental sciatic nerve injury

The aim of this study was to investigate the effects of boric acid in experimental acute sciatic nerve injury. Twenty-eight adult male rats were randomly divided into four equal groups(n = 7): control(C), boric acid(BA), sciatic nerve injury(I), and sciatic nerve injury + boric acid treatment(BAI). Sciatic nerve injury was generated using a Yasargil aneurysm clip in the groups I and BAI. Boric acid was given four times at 100 mg/kg to rats in the groups BA and BAI after injury(by gavage at 0, 24, 48 and 72 hours) but no injury was made in the group BA. In vivo electrophysiological tests were performed at the end of the day 4 and sciatic nerve tissue samples were taken for histopathological examination. The amplitude of compound action potential, the nerve conduction velocity and the number of axons were significantly lower and the myelin structure was found to be broken in group I compared with those in groups C and BA. However, the amplitude of the compound action potential, the nerve conduction velocity and the number of axons were significantly greater in group BAI than in group I. Moreover, myelin injury was significantly milder and the intensity of nuclear factor kappa B immunostaining was significantly weaker in group BAI than in group I. The results of this study show that administration of boric acid at 100 mg/kg after sciatic nerve injury in rats markedly reduces myelin and axonal injury and improves the electrophysiological function of injured sciatic nerve possibly through alleviating oxidative stress reactions.

Preparation of Boric-10 Acid Applied in Nuclear Industry

Because of the superior features of boron-10 isotope in absorbing hot neutrons, boric-10 acid(H310BO3)has been used widely in nuclear industry. Boric-10 acid is obtained from boron-10 trifluoride(10BF3) by esterification and hydrolyzation. In this study, trimethyl borate-10 [(CH3O)310B] was prepared from boron-10 trifluoride(10BF3)through chemical exchange rectification. In addition, the hydrolyzation of trimethyl borate-10 was investigated with different p H values, temperatures and molar ratios of water to trimethyl borate-10. Under the optimum process conditions, high yield of boric-10 acid with nuclear industrial purity grade was realized.

Study of Cross-Linking between Boric Acid and Different Types of Polyvinyl Alcohol Adhesive

Polyvinyl alcohol (PVA) is water-soluble polymer manufactured by the saponification of polyvinyl acetate. The physical properties and its specific application depend on the degree of hydrolysis. To enhance the properties of different hydrolyzed PVA grades, it is generally chemically modified with various cross-linkers. Here, different degree hydrolyzed PVA grades with enhanced properties were achieved by cross-linking with boric acid. These samples were then characterized by Differential Scanning Calorimetry (DSC) and Gel permeation chromatography (GPC). For further analysis a film of samples were prepared by casting on glass plate. The effects of amount of boric acid and degree of hydrolysis of PVA on performance properties like tensile strength, pencil hardness and thermal properties like glass transition temperature were studied. The results showed that by cross-linking there was an increase in mechanical strength and thermal property.

A Wood Preservative Based on Commercial Silica Nanodispersions and Boric Acid against Fungal Decay through Laboratory and Field Tests

The paper is based on the development of a wood preservative without metal salts to be used in use classes 3 and 4 (EN 335), eco-friendly and harmless to humans and animals. Boric acid was used as a biocide, due to its effectiveness against fungi and insects. It is also known to be easily leached from wood exposed to weather action. Colloidal silica was therefore added in the formulations to guarantee the fixation of boric acid to wood. The different formulations were tested for the protective efficacy against decay fungi through laboratory tests (EN 113) and field trials (EN 252). The results were promising, especially those concerning boron fixation and efficacy against decay fungi through laboratory tests, where some formulations and retentions gave a durability class 1 (very durable) according to EN 350-1. The fourth evaluation, after 50 months of field trials showed only a slight difference between the treated samples and controls.

Improvement of Selectivity with Boric Acid in Separating Phenolic Acids by Capillary Zone Electrophoresis

It was shown that in capillary electrophoresis (CE) the addition of boric acid as a complexing agent in phosphate buffer can modulate the separation selechvity of phenolic acids.

Preparation of anodic films on 2024 aluminum alloy in boric acid-containing mixed electrolyte

The anodizing oxidation process on 2024 aluminum alloy was researched in the mixed electrolyte with the composition of 30 g/L boric acid, 2 g/L sulfosalicylic acid and 8 g/L phosphate. The results reveal that the pre-treatment and the composition of the mixed electrolyte have influence on the properties of the films and the anodizing oxidation process. Under the condition of controlled potential, the anodizing oxidation current—time response curve displays "saddle" shape. First, the current density reaches a peak value of 8-20 A/dm2 and then decreases rapidly, finally maintains at 1-2 A/dm2. The film prepared in the mixed electrolyte is of porous-type with 20 nm in pore size and 500 μm-2 in porosity. Compared with the conventional anodic film obtained in sulfuric acid, the pore wall of the porous layer prepared in this work is not continuous, which seems to be deposited by small spherical grains. This porous structure of the anodic film may result from the characteristics of the mixed electrolyte and the special anodizing oxidation process. The surface analysis displays that the anodic film is amorphous and composed of O, Al, C, P, S, Si and no copper element is detected.

Effect of Boric Acid on Properties of Calcined Flint Clay-bauxite Castables

In order to prolong the working time of calcined flint clay-bauxite castables during construction at high temperature,boric acid was added into the castables. The effect of boric acid on working time and curing cold crushing strength of the castables at 25 ℃ and 35 ℃ were investigated. After 24 h curing in mould and another 24 h curing at 110 ℃ after demoulding,the specimens were heat treated at 1 000 ℃,1 300 ℃,and 1 500 ℃ for 3 h,respectively. The permanent linear change,bulk density,modulus of rupture,and cold crushing strength were determined. The result shows that there is no need to add boric acid when calcined flint clay-bauxite castables works at 25 ℃; when calcined flint clay-bauxite castables works at 35 ℃,boric acid can increase the working time of the castables,but decrease the curing cold crushing strength a little. Adding boric acid into calcined flint clay-bauxite castables doesn't worsen performance of the castables.

Preparation of boric acid from low-grade ascharite and recovery of magnesium sulfate

Boric acid and kieserite were prepared from low-grade ascharite by sulfuric acid method.This method results in the recovery of 71.06%and 45.03%for boric acid and kieserite,respectively.Meanwhile,the boric acid was precipitated from the filtrate at low temperature and the solution was recycled without discharging waste liquid in the whole process.The influence of amount of sulfuric acid,mass fraction of sulfuric acid,reaction temperature and reaction time on the leaching rate of boric acid were studied. The results show that the leaching rate of boric acid reaches 93.80%under the following conditions:the amount of sulfuric acid is 85%of theoretical dosage;the mass fraction of sulfuric acid is 25%;reaction temperature is 95℃;and the reaction time is 100 min. Meanwhile,the effects of mass fraction of magnesium sulfate,crystallization temperature and crystallization time on the crystallization of kieserite were investigated and the optimal crystallization conditions are obtained:the mass fraction of magnesium sulfate is 28%;the crystallization temperature is 180℃and the crystallization time is 4h.

An efficient synthesis of 1,5-benzodiazepine derivatives catalyzed by boric acid

1,5-Benzodiazepine 衍生物被 o-phenylenediamines 和酉同类的冷凝作用综合了面对硼酸象在温和条件下面的催化剂酸。这个方法简单，慈祥、高产出的环境联盟者。

Preparation and Characterization of High Purity Enriched 10B Boric Acid via Anti-Solvent Recrystallization

Self-made enriched 10 B boric acid as raw material was purified by recrystallization. The effects of final crystallization temperature, crystallization time, stirring speed, crystallization frequency and other factors on the purity were investigated. The appropriate operating condition was that the final crystallization temperature and time were 5,℃ and 10 h respectively under a low-speed stirring for crystallizing twice, which would make the purity and yield of boric acid reach 99.94% and 95.36%, respectively. Taking this as foundation, recrystallization process was optimized with acetone as anti-solvent, whose amount was the most important index. The boric acid solution was added into acetone and recrystallized under the same condition, and the purity and yield of boric acid would reach 99.98% and 99.61%, respectively. The product detected by XRD was confirmed as boric acid crystal. Main ion concentration in the product was detected by ICP, which basically met the national standard of high purity. Crystal morphology of boric acid was observed by SEM.

Boric acid as an efficient catalyst for the synthesis of 1,1-diacetate under solvent-free condition

硼酸酸(BO 3 H 3) 是为 1,1-diacetate (acylal ) 的合成的便宜、有效、温和的催化剂从各种各样芳香并且有在在没有溶剂的状况下面的房间温度的醋性的酐的异种芳基醛。现在的方法不包含任何危险器官的溶剂或催化剂。这个方法给象优秀 chemoselectivity，温和反应条件，短反应时间和优秀产量那样的著名优点。

Determination of Iron in Layered Crystal Sodium Disilicate and Sodium Silicate by Flame Atomic Absorption Spectrometry with Boric Acid as a Matrix Modifier

The effects of matrix silicate and experimental conditions on the determination of iron in flame atomic absorption spectrometry (FAAS) were investigated. It was found that boric acid as a matrix modifier obviously eliminated silicate interference. Under the optimum operating conditions, the determination results of iron in layered crystal sodium disilicate and sodium silicate samples by FAAS were satisfactory. The linear range of calibration curve is 0-10.5 μg·mL-1, the relative standard deviation of method is 1.2%-2.2%, the recovery of added iron is 96.0%-101%, the sensitivity is 0.19 μg·mL-1, and the detection limit is 77 ng·mL-1. The effect of the determination of iron of the standard curve method, standard addition calibration and colorimetry method was the same, but the first has the merits of rapid sample preparation, reduced contamination risks and fast analysis.

Nanoscale Properties of Boric Acid

Nanoscale properties of boric acid were studied by using atomic force microscopy (AFM) and nanomechanical testing system. XPS was used to research on the transform behaviors of H 3BO 3 at different temperatures. The crystal structure, surface morphology, and mechanical properties of H 3BO 3 were described. The results show that H 3BO 3 has layered structure, and can be transformed to boron oxide at high temperature. In addition there are a lot of defects in H 3BO 3 crystal.

从高钙富硼老卤中提硼研究

以青海某高钙富硼老卤为研究对象开展了提硼研究。结果表明,合适的萃取条件为:磺化煤油为稀释剂、异辛醇用量50%、萃取相比1.0、萃取混合时间15 min;合适的反萃条件为:反萃剂为pH=1的稀盐酸、反萃相比1.5、反萃混合时间15 min。以此条件在5级混合澄清槽中完成了连续逆流萃取—反萃运转试验,连续运转45 h,硼萃取率为95.49%,硼与钾、钠、钙、镁的分离效果较好;硼反萃率为99.59%,反萃液中硼含量达17.17 g/L。采用“溶剂萃取—反萃—高温蒸发—低温冷却结晶—重溶—冷却结晶—过滤洗涤—干燥”工艺高效分离提取硼,硼总回收率为92.33%,制备出的硼酸产品达国家标准(GB/T 538—2018)要求。

拉曼积分球光谱仪对盐水溶液中B(OH)_(3)的定量分析

不同溶液体系中硼的赋存形态及其化学分布规律一直以来是研究者关注的重点,它对深入开展硼酸盐溶液结构化学、过饱和非平衡态以及硼酸盐矿物沉积机制等研究具有重要的指导意义。针对目前拉曼光谱仪对溶液中硼氧配阴离子官能团响应信号弱、灵敏度低,不利于定量化视角阐述硼氧配阴离子间的作用机理等问题,研究了拉曼积分球光谱仪对硼酸溶液的定量分析方法,运用DOE部分因子实验设计,阐述了NaCl、MgCl_(2)、KCl和MgSO_(4)等共存盐类之间的交互作用对B(OH)_(3)拉曼定量分析的影响规律,建立了盐水溶液中B(OH)_(3)的Raman回归模型。结果表明,拉曼积分球光谱仪可显著增大硼酸溶液的拉曼光谱强度,提高信噪比,检出限为常规拉曼光谱的70倍,在0~6 g·L^(-1)硼酸线性范围内相关系数为0.9991,测定相对误差为-2.5%;盐水溶液中B(OH)_(3)含量经回归方程校正后相对误差绝对值小于3%,可用于低浓度硼酸的准确定量分析,也为定量化探究盐卤复杂体系中多硼物种化学形态分布规律提供一定借鉴。