The reaction of kaolin with fluorides: I. Effect of neutral and acid sodium fluoride solutions

The reaction between kaolinite and neutral and acid sodium fluoride solutions was investigated at different temperatures and over the acid pH range. The stoicheiometric replacement of hydroxyls in the kaolinite crystal lattice by fluoride ions, as reported by earlier workers, was not confirmed. The release of hydroxyl ions into solution was due predominantly to the disruption of the kaolinite crystal lattice. In the presence of sodium ions and at pH < 7, sodium fluoro-silicate and cryolite were found as solid phases. At pH > 7, only cryolite was found as a solid phase. Small, spherical, particles were observed in all cases. These particles were believed to be amorphous silica, formed as an intermediate phase in the disruption process.     

The reaction of kaolin clay with orthophosphoric acid

Conclusions Orthophosphoric acid reacts with kaolinite clay already at room temperature. The reaction results in the dissociation of some kaolinite and the formation of acid aluminophosphates, its rate is at maximum during the first 4–10 days of the storage of the composition of clay with the acid, and it ceases when the composition is stored for longer periods.The triderivative of aluminophosphate begins to form only on heating above 100°C. At a temperature of 400°C and higher it forms more rapidly while the proportion of mono- and diderivatives of aluminophosphates diminishes.The fact that in compositions of kaolinite clay with orthophosphoric acid in storage only water-soluble acid aluminophosphates are formed and triderivative of aluminophosphate is absent makes it possible to produce clay-containing aluminosilicate compositions containing orthophosphoric acid at refractory plants in ready-for-use form.Translated from Ogneupory, No. 7, pp. 43–48, July, 1977.     

The reaction of kaolin with fluorides. III. Hydrolysis of silicon tetrafluoride by kaolinite at elevated temperatures

The reaction between kaolinite and silicon tetrafluoride has been studied over the temperature range 300–700°. Above the dehydroxylation temperature of kaolinite the formation of metakaolinite was accompanied by an increase in sample weight rather than a loss. In the presence of an excess of SiF₄ the reaction products showed signs of interaction with one another, possibly to form a fluoroaluminate.     

The reaction of picric acid with epoxides. II. The detection of epoxides in heated oils

A colorimetric method, based upon the reaction of the oxirane group with picric acid, was used to determine the epoxide content of heated vegetable oils. The picration method is particularly suitable for measuring small quantities of epoxide because it is much more sensitive than the common titrimetric methods, and it is not subject to interference from cyclopropene, conjugated dieneols, or α, β-unsaturated carbonyls. Thin-layer chromatography was used to separate mixtures of picrated, epoxidized methyl esters. Separation ofcis- andtrans-methyl epoxystearate, methyl epoxyoleate, and methyl diepoxystearate in a mixture of these four esters was achieved in this manner. The presence of saturatedcis- andtrans-epoxystearates and unsaturated epoxides was demonstrated in heated vegetable oils. Presented, in part, at the AOCS Meeting in Cincinnati, October 1965.     

Electrochemical corrosion behavior and surface modification of ZrB2 in hydrofluoric acid aqueous solution

The electrochemical corrosion behavior in an open system of zirconium diboride (ZrB₂) was studied in hydrofluoric acid aqueous solution at room temperature. Based on analysis of the intermediate products of corrosion, a corrosion mechanism for ZrB₂ is suggested. The morphology evolution of anodic ZrB₂ is investigated. The density of the hexagonal‐pyramid grain array is dictated by current density, and the time dictates the length of the hexagonal pyramid grains. The microstructure of the surface can be controlled by the current density, which demonstrates that the surface wettability of ZrB₂ can be modified by tailoring the current density.     

High temperature reaction of kaolin with inorganic acids

Abstract

A new method is described in which raw materials prepared by mixing kaolin and concentrated acid are heated in a furnace at temperatures between 100 and 700°C. Experiments with HCl, HNO₃, H₃PO₄, and H₂SO₄ showed that only H₂SO₄ gave high reaction yields, which grew steadily as reaction temperature was raised. Reaction products were mostly Al₂(SO₄)₃. Leached kaolin samples showed BET specific surface areas of over 100 m² g^-1. Furthermore, reaction between kaolin and H₂SO₄ required no previous calcination of kaolin.     

Solubility of linoleic acid in aqueous solutions and its reaction with water

In a study of stable emulsions of linoleic acid in 0.1M-KH₂PO₄/Na₂HPO₄ buffer solutions prepared by sonic vibrations, the influence of linoleic acid on pH was manifested in buffer solutions of pH 8.00 and decreased gradually till it became negligible in pH 4.50. This change in pH values was due to differences in solubility of linoleic acid in the buffer solutions. Ultraviolet spectra of soluble linoleic acid in buffer solutions indicated the presence of conjugated dienes, which increased with the increasing of the pH of the system. Unbuffered aqueous emulsions of linoleic acid had a pH value which ranged between 4.69 and 5.10. Saturated aqueous solutions, obtained by high-speed centrifugation, had concentrations of 15.80 to 16.00 mg. linoleic acid per 100 ml. of D.I. water. From the solubility data and conductivity values of linoleic acid the apparent classic and thermodynamic ionization constants were calculated to be 6.974±0.023×10⁻⁶ and 6.905±0.017×10⁻⁶ at 0.7°C. and 1.730±0.009×10⁻⁵ and 1.689±0.007×10⁻⁵ at 25°C., respectively. The result of the chemical interaction of linoleic acid and water is a saturated hydroxy fatty acid. This acid gave a positive test for glycol groups with periodic acid oxidation test and appeared to be a tetrahydroxy compound with the exact structure unknown. Presented at the 51st Annual Meeting, American Oil Chemists' Society at Dallas, Tex., April 4–6, 1960. American Meat Institute Foundation Journal Paper No.204.     

氟硼酸/氢氟酸复合体系的研究与应用

针对常规酸液体系在低渗透储层应用效果不理想、溶蚀性能偏低的问题,采用盐酸、氟硼酸和氢氟酸3种酸液复合的思路,使得酸液体系同时具备强溶蚀性和缓速性.通过正交试验法,优选了合适的酸液浓度配比,该配比针对现场岩屑样品溶蚀率可高达24.8％?40.6％;进行了高温缓蚀剂优选,添加高温缓蚀剂后的氟硼酸/氢氟酸复合体系在温度160...     

以氢氟酸协同草酸精制石英砂尾矿及其作用机理

高纯度石英砂在建筑、玻璃制造、铸造等工业领域应用广泛,将石英砂尾矿进行除Fe、Al处理,能够得到相当于高纯度石英砂的替代产品。本研究采用广东河源石英尾矿为原料,提出以氢氟酸协同草酸精制石英砂尾矿的方法,并确定最佳的条件。通过对草酸Fe³⁺溶解络合实验,确定了草酸用量与反应温度;通过HF协同草酸精制实验,确定了酸浸反应时间与物料比例。结果表明,80℃时200g粒径60目的石英砂尾矿在100mL饱和草酸溶液与HF比为25:1(体积比)的酸浸液中,浸泡4h时对石英尾矿的处理可以达到精制的目的。精制后石英砂中二氧化硅含量可以达到99.97%,白度达87.5.实验表明,通过补加草酸与HF可实现精制液的循环应用。冷却失效的精制液可回收结晶析出的草酸,剩余精制液与石英砂水洗液一起进行尾液处理。尾液处理采用饱和澄清石灰水将废液中的杂质沉淀析出,尾液与饱和澄清石灰水的体积比为1:13时处理效果最好,处理后可以达到中水的排放标准。     

液下屏蔽电泵在氟化氢领域的应用

输送无水氟化氢的液下屏蔽泵常发生泵被卡死、电流偏高、打不起流量等故障,分析了输送无水氟化氢的液下屏蔽泵产生故障的原因,并进行了轴承、轴套、推力盘等相应的改造,保证了屏蔽泵的长周期稳定运行。     

Diffusion with simultaneous reaction of reactive dyes in cellulose. II. Effect of hydrolysis

Theoretical equations that describe the concentration profiles of immobilized and active species for reactive dyes were derived from the diffusion equation accompanied by the reaction with cellulose and water in the substrate. The diffusion coefficient D and the rate constant of the reaction with cellulose, k_cell, and that with water in cellulose, k_w, were estimated by using the theoretical equations and the cylindrical film roll method. The theory predicted that the apparent diffusion coefficients decreased with the hydrolysis of active species in cellulose. Results from diffusion experiments with C.I. Reactive Yellow 4 and Orange 1 show that the ratio P of k_w to k_cell for Orange 1 increased with increase in pH to about pH 13 and that the P for Yellow 4 was smaller than unity. Using an alternative experiment to diffusion, P of Orange 1 was measured to be 1.0–1.5, and that of Yellow 4 was smaller than unity at pH 11.6 at 30°C. It was therefore concluded that the D of active species was constant to a highly alkaline region and that the decrease in the apparent diffusion coefficient of Orange 1 was mainly due to the hydrolysis of active species in cellulose.     

The oxidation of methyl oleate. II. A reaction between methyl hydroperoxido oleate and oleic acid

Oleic acid is intermolecularly oxidized by methyl hydroperoxido leate at 90°C, through the addition of oxygen at the olefinic bond with the formation of opexy and dihydroxy compounds. Only the lowmelting isomeric form of dihydroxystearic acid could be isolated from the reaction mixture. The oxidation of olefinic linkages by hydroperoxides appears to account, at least in part, for the observed reduction of unsaturation in autoxidizing fats. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

Polymerisation of dec-1-ene. II. Effect of reaction temperature

The effect of temperature on the polymerisation of dec-1-ene has been studied, the catalysts used being (a) a catalyst prepared by mixing triethylaluminium and titanium tetrachloride at a molar ratio of 0.3:1 and (b) aluminium chloride. Polymers prepared at room temperature with triethylaluminium/titanium tetrachloride contain an average of one double bond per molecule. Increase in temperature from 20 to 150° produces saturated polymers of higher viscosity. The loss of olefinic unsaturation is due to cyclisation reactions, which produce aromatics and cycloalkanes, and to disproportionation reactions. An increase in reaction temperature from 20 to 150° with aluminium chloride as catalyst has little effect other than to reduce the viscosity of the polymer. The polymers produced at high temperatures by both catalyst systems are very similar. It is concluded that the active catalyst species in the triethylaluminium/titanium tetrachloride system at 150° is aluminium chloride or a complex containing it.     

热活化对氢氟酸法制备高纯石墨的影响

针对氢氟酸法提纯石墨因环保投入导致成本较高的现状,进行了热活化结合氢氟酸法提纯石墨的研究。结果表明:对经氢氟酸法初步提纯过的石墨中剩余杂质进行热活化处理,其提纯效果远优于常规氢氟酸法,不但可将原料固定碳含量由86.42%提高至99.98%,而且氢氟酸用量也显著减少,生产成本明显降低。     

Polyaniline synthesis using hydrofluoric acid as doping agent: Comparative evaluation with polyaniline doped with sulfuric acid

This work focuses on the comparison between the morphological, chemical, and electrical properties of polyaniline doped with fluoridric and polyaniline, and doped with sulfuric acid. The FT‐IR, XRD, and SEM/EDS results indicate that the use of hydrofluoric acid as doping agent does not provide meaningful changes in the crystalline and morphological structure of polyaniline. Although, the inclusion of F^? type counter‐ions from the doping process with HF provide more compact, denser, and with higher electrical conductivity polymeric matrices. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013     

煅烧高岭土的硬脂酸改性及其性能研究

研究了硬脂酸对山西怀仁地区煤系煅烧高岭土的表面改性方法,并对改性高岭土进行了红外光谱表征和活化指数、吸油量等性能的测定。实验结果表明,用3%的硬脂酸对煅烧高岭土改性后,活化指数达100%,吸油量可降低40%左右。将其加入聚氨酯中,可明显提高煅烧高岭土和聚氨酯高分子的亲和能力。