Metaborate product

Knowing that the major limitation to reach the theoretical 10.9 wt% H2 storage density by hydrolysis of NaBH4 powder with water is the hydration level of the metaborate product, to attain a higher H2 storage density, a higher temperature of the system is required for dehydrating the metaborate products, and an easy way to reach this objective is to utilize the thermal effects of hydrolysis. 

Although there is Httle toxicity information pubHshed on hydrides, a threshold limit value (TLV) for lithium hydride in air of 25 fig/has been established (52). More extensive data are available (53) for sodium borohydride in the powder and solution forms. The acute oral LD q of NaBH is 50-100 mg/kg for NaBH and 50-1000 mg/kg for the solution. The acute dermal LD q (on dry skin) is 4-8 g/kg for NaBH and 100-500 mg/kg for the solution. The reaction or decomposition by-product sodium metaborate is slightly toxic orally (LD q is 2000-4000 mg/kg) and nontoxic dermally. 

Reaction of phenyl metaborate with formaldehyde, followed by catalytic oxidation, has been reported to give sahcylaldehyde selectively and directiy from phenol without isolation of any intermediate products (63). 

Barium metaborate is used as an additive to impart fire-retardant and mil dew-resistant properties to latex paints, plastics, textiles, and paper products (6). Barium metaborate is marketed by Buckman Labs, Inc., Memphis, Tennessee (12). 

You have added a solution of calcium chloride to a solution of sodium metaborate. A crystalline precipitate resulted. In attempting to analyze your product. 

Fusion with boric acid at high temperature forms lead metaborate that has an approximate composition Pb(B02)2 H20. The product loses water of crys-taUization at 160°C. 

B2O3. Production processes have been developed for metaboric acid, but to date it has not become commercially important and is not currently produced in any substantial quantities. 

The principal impurities in technical-grade boric acid are the by-product sulfates, <0.1 wt %, and various minor metallic impurities present in the borate ores. A bone acid titer is not an effective measure of purity because overdrying may result in partial conversion to metaboric acid and lead to B(OH)3 assays above 100%. High purity boric acid is prepared by recrystallization of technical-grade material. 

In conclusion, field dependent single-crystal magnetization, specific-heat and neutron diffraction results are presented. They are compared with theoretical calculations based on the use of symmetry analysis and a phenomenological thermodynamic potential. For the description of the incommensurate magnetic structure of copper metaborate we introduced the modified Lifshits invariant for the case of two two-component order parameters. This invariant is the antisymmetric product of the different order parameters and their spatial derivatives. Our theory describes satisfactorily the main features of the behavior of the copper metaborate spin system under applied external magnetic field for the temperature range 2+20 K. The definition of the nature of the low-temperature magnetic state anomalies observed at temperatures near 1.8 K and 1 K requires further consideration. 

Hexane (99% n-hexane) was obtained from Aldrich. Silica was obtained as a 30% Colloid (LUDOX-HS, 30 wt% SiOj) from DuPont. Aluminum hydroxide, boron oxide, and sodium metaborate were obtained from Alfa Products. Boric acid was obtained from J. T. Baker. Commercial samples of mordenite and zeolite Y were obtained from the Norton and Union Carbide Companies, respectively. A specific example which illustrates the typical procedure used for preparing mordenite and zeolite Y from gels is given below. 

The product of the decomposition is, like in the Millennium Cell system, sodium metaborate. The system shows the same problems for the regeneration of NaBH4 from an aqueous solution of metaborate as described below. One advantage of the direct borohydride fuel cell systems is that platinum as catalyst is not needed. Unfortunately, depending on the temperature of the solution, some hydrogen gas is produced in a side reaction. However, this hydrogen can be piped out or can be used as additional fuel in a subsequent PEM fuel cell. 

Forms unstable explosive products in reaction with acetaldehyde + desiccants (forms polyethyUdine peroxide) acetic acid (forms peracetic acid) acetic + 3-thietanol acetic anhydride acetone (forms explosive peroxides) alcohols (products are shock-and heat-sensitive) carboxylic acids (e.g., formic acid, acetic acid, tartaric acid), diethyl ether, ethyl acetate, formic acid -f- metaboric acid, ketene (forms diacetyl peroxide) mercur f(II) oxide + nitric acid (forms mercur f(II) peroxide) thiourea -f- nitric acid polyacetoxyacryUc acid lactone + poly(2-hydroxyacrylic acid) + sodium hydroxide. 

Attempts to prepare uranyl borate from UO3 instead of U3O8 were only partially successful. The trioxide is more reactive than U3O8 and eliminates the necessity for an oxidation step in the metaborate synthesis reaction, but the low thermal stability of UO3 restricts the reaction temperature to <650°C. Infrared and x-ray analyses of products obtained after heating UO3 and B2O3 mixtures for several days at 650°C. indicated that only a minor conversion to the metaborate had been effected. 

Analyses. Elemental analyses of the solid products were obtained by fusing the sample with lithium metaborate at 1000° C and then dissolving the melt in 10% HCl. The resulting solutions were diluted to 100.0 ml and were analyzed by atomic absorption (Varian techtron model 385). Cations in leachates were also measured with this instrument. 

Inductively coupled plasma atomic emission spectrometry (ICP-AES) was used for the determination of most major and trace elements. The samples are fused in a Claisse semi-automatic fusion device in Pt-Au crucibles with lithium metaborate (4). The fusion product is dissolved in diluted HNO and brought to volume. For trace elements determination the sample is decomposed by HF, HNOg and HCIO. Scandium serves as an internal standard and is added to all samples and solutions. The instrument (product of Jobin Yvon, France)is calibrated using multi-element synthetic standards. The aqueous solutions are nebulized and injected into the heart of a plasma fire ball. A computerized multi-channel vacuum spectrometer has been programmed for multi-element analysis. 

Barium metaborate is a truly multifunctional additive which inhibits corrosion, increases UV stability, inhibits mold growth, and has flame retarding properties when used in combination with halogenated materials. The commercial product of Buckman Laboratories is a modified product which contains 90% of active ingredient. 

In the course of the reaction three molecules of sodium metaborate appear as a by-product. The addition of a further three molecules of hydrogen peroxide converts these as well into perborate. 

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