Boron, Boric Acid and Borax

Inorganic Esters. Boric acid and borax form cycHc esters with poly(vinyl alcohol) (85—100). The reaction is markedly sensitive to pH, boric acid concentration, and the cation-to-boron ratio. An insoluble gel is formed at pH above 4.5—5.0 ... 

Borax pentahydrate is an effective flame retardant for wood/cellulosic materials in terms of surface flammability. However, due to the Na20 moiety, it can promote smoldering combustion in cellulose. Thus, in cellulosic material and wood products, it is commonly used in combination with boric acid, which is an effective smoldering inhibitor. For example, the treatment of wood fibers with a partially dissolved boric acid and borax pentahydrate slurry (-1.75% by wt. of boron) results in Medium Density Fiberboard (MDF) that is claimed to pass the ASTM E-84 Class 1 surface flammability standard.12 The additional examples of using borax pentahydrate and boric acid combination are presented in Section 9.2.2.1. 

Boron is an essential trace plant nutrient. Although its exact function has not yet been established, deprivation of boron alfects plant growth and in boron-poor soils, crop yields are diminished. An important application of borax is in borate fertilizers. In contrast, the toxicides of boric acid and borax to animal life are sufficient for them to be used as insecticides,... 

Boron is a dark brown element that is widespread in the environment but occurs naturally only in combined form, usually as borax, colemanite (Ca2B60n 5H20),boronatrocal-cite (CaB40yNaB02 8H2O), and boracite (MgyCbBieOso). In the United States, boron deposits in the form of borax are concentrated in the desert areas of southern California, especially near Boron, California. Proven deposits of sodium tetraborates - from which borax is prepared and from which boron can be isolated - also exist in Nevada, Oregon, Turkey, Russia, and China. About 300,000 metric tons of boron are removed from mined ore each year. The United States supplies about 70% of the world boron demand, and Turkey supplies 18% the most common commercial compounds are boric acid and borax. 

Boron occurred at high concentrations in plants, insects, and fishes at KNWR in California - the recipient of contaminated agricultural drainwater - when compared to a nearby control area. Both boric acid and borax produced mortality and teratogenic development when injected into eggs. The effects of boron on waterfowl growth, physiology, and reproduction are discussed later. 

Boron is a metalloid that occurs in nature mainly as borate minerals, such as borax, Na2B405(0H)4-8 H2O, and borosilicates. In biological material, compounds of boron (boric acid and borates) form stable complexes with polyhydroxy compounds, such as sugar alcohols, sugars and substances derived from them (nucleotides, riboflavin and ascorbic acid). An example is the binding of boric acid, B(0H)3 or more accurately of borate ions, to the ds-hydroxyls (at positions C-2 and C-3) oftwo P-o-apiose residues (6-39) located in different chains of a structural type of pectin called rhamno-galacturonan II, which are cross-linked in this way (see Section 4.5.6.6.1). 

Decahydrate, Pentahydrate, and Anhydrous Borax and Bulk Calcium Borates. The bulk borate products, borax decahydrate and pentahydrate, anhydrous borax, boric acid and oxide, and upgraded colemanite and ulexite, account in both toimage and monetary terms for over 99% of sales of the boron primary products industry (6). Economic considerations for all these products are highly interrelated, and most production and trade statistics do not distinguish the various products. 

The chemistry of boron is exceedingly complex and rivals that of carbon in its diversity. Most boron compounds, however, enter or degrade in the environment to borates (B-0 compounds), such as borax and boric acid, and these are considered to be the most significant ecologically. 

Toxicosis in animals has resulted from ingestion of boric acid or borax solutions, from topical applications of boric acid solutions to damaged skin, and from inhalation of boranes the exact mechanisms of action are not understood. Boron and its compounds are potent teratogens when applied directly to the embryo, bnt there is no evidence of mutagenicity or carcinogenicity. Boron s unique affinity for cancerons tissnes has been exploited in neutron capture radiation therapy of malignant hnman brain tnmors. 

Relatively high concentrations of boron componnds are used to control fruitflies, cockroaches, gypsy moth larvae, houseflies, and woodboring insects (Sprague 1972 USEPA 1975 Table 29.6). Boric acid is an effective stomach poison for several insect species, including German cockroaches (Blattella germanica), that are unable to detect the presence of boric acid (USEPA 1975). Insect infestation of wood and other substrates can be prevented by pretreatment with boric acid or borax at... 

BORONCOMPOUNDS - BORON OXIDES, BORIC ACID AND BORATES] (Vol 4) Disodium tetraborate decahydrate (borax) [1303-96-4]... 

The main source of boron is a complex compound of boron called borax. About half of the world supply of borax comes from a large deposit in California s Mojave Desert. Borax is used as a cleaning agent and as fireproof insulation. Another compound of boron, boric acid, is used as a disinfectant and as an eye wash. A form of boron nitride is the second hardest known material only diamond is harder. These materials are classified as superabrasives. They are used in grinding wheels, which shape manufactured parts and tools. 

Boron, an element, occurs in many compounds, including borax, borates, boric acid, and carboxyboranes used in glass, ceramics, detergents, bleaches, fire retardants, disinfectants, alloys, specialty metals, preservatives, pesticides, and fertilizers (Mastromatteo and Sullivan 1994). Boron compounds also constitute an important group of dopants in the semiconductor industry. Dopants alter crystalline substrates electrical conductivities in the manufacturing of diodes, transistors, and capacitors (Lewis 1986). 

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