Flame boron-containing

Recently, several reports of the flame-retardant properties of boron-containing bisphenol-A resins have appeared from Gao and Liu.89 The synthesis of a boron-containing bisphenol-A formaldehyde resin (64 and 65) (Fig. 42) from a mixture of bisphenol-A, formaldehyde, and boric acid, in the mole ratio 1 2.4 0.5, has been reported.893 The kinetics of the thermal degradation and thermal stability of the resins were determined by thermal analysis. The analysis revealed that the resin had higher heat resistance and oxidative resistance than most common phenol-formaldehyde resins. 

Fig. 15.20 Theoretical flame temperature versus air-to-fuel ratio of a boron-containing pyrolantwith and without boron combustion.

P. Armitage, J.R. Ebdon, B.J. Hunt, M.S. Jones, and F.G. Thorpe, Chemical modification of polymers to improve flame retardance. I. The influence of boron-containing groups. Polym. Degrad. Stab., 54, 387-393 (1996). 

Functional polymers in which boron-containing groups permit to tailor the physical and/or chemical properties of the materials (e.g., flame retardants, neutron capture/ sensor systems, reversible hydrogen storage, optoelectronic or biomedical applications)... 

Kaneka has proposed flame retardants containing both silicon and boron, such as the reaction product of phenyl trichlorosilane and boric acid. Borealis has patented a polyolefin wire and cable composition containing metal hydroxides and a small quantity of an organosiloxane containing methyl, phenyl, vinyl or similar side-groups. 

In spite of the few thousands of references on flame retardants, only a small number of compounds are commercially produced as such. They are mainly phosphorus, antimony, aluminum, and boron-containing compounds, chlo-... 

M.A. Kasem and H.R. Richards, Flame-retardants for fabrics, function of boron-containing additives, Ind. Eng. Chem. Prod. Res. Dev., 11(2) 114 133, June 1972. 

Boron also reacts with hydroxyl-containing polymers such as cellulose. When exposed to a flame the boron and hydroxyl groups form a glassy ester that coats the substrate and reduces polymer degradation. A similar type of action has been observed in the boron—alumina tfihydrate system. 

The most commonly used and widely marketed GC detector based on chemiluminescence is the FPD [82], This detector differs from other gas-phase chemiluminescence techniques described below in that it detects chemiluminescence occurring in a flame, rather than cold chemiluminescence. The high temperatures of the flame promote chemical reactions that form key reaction intermediates and may provide additional thermal excitation of the emitting species. Flame emissions may be used to selectively detect compounds containing sulfur, nitrogen, phosphorus, boron, antimony, and arsenic, and even halogens under special reaction conditions [83, 84], but commercial detectors normally are configured only for sulfur and phosphorus detection [85-87], In the FPD, the GC column extends... 

Preparation of Amorphous Boron from Boric Acid Anhydride. (Each student performs only one of the experiments for preparing amorphous boron.) Put 2 g of boric acid anhydride into an iron crucible or onto an iron plate and roast it if the boric acid anhydride contains moisture, then when it is heated with magnesium an explosion may occur ). Triturate the boric acid anhydride as rapidly as possible (why ) in 4 mortar, weigh 1 g and mix it with 2 g of a magnesium powder. Place the mixture into a refractory test tube and fasten it in an inclined position in a clamp of a stand in a fume cupboard . First carefully heat the test tube with the mixture with the flame of a burner, and then strongly heat the bottom part of the tube. What do you observe ... 

The spectra of a number of triatomic radicals with 15 valence electrons are now known for elements of the first period they are B02, N3, and NCO. In addition, the isoelectronic ions C02+ and N20+ have been investigated. The spectrum of B02 was observed by Johns41 in the flash photolysis of a mixture of BCI3 and 02, but later was found to be identical to the green bands observed in most flames and arcs containing boron.42 Isotope shifts (B1X-B10) and alternate missing lines in the spectrum immediately identify the carrier as... 

SYNTHESIS A solution of 76.6 g 2,5-dimethoxyaniline in 210 mL H20 containing 205 mL fluoroboric acid was cooled to 0 °C. with an external ice bath. There was then added, slowly, a solution of 35 g sodium nitrite in 70 mL H20. After an additional 0.5 h stirring, the precipitated solids were removed by filtration, washed first w ith cold H20, then with MeOH and finally Et20. Air drying yielded about 100 g of the fluoroborate salt of the aniline as dark purple-brown solids. This salt was pyrolyzed with the cautious application of a flame, with the needed attention paid to both an explosion risk, and the evolution of the very corrosive boron trifluoride. The liquid that accumulated in the receiver was distilled at about 120 °C at 20 mm/ Hg, and was subsequently washed with dilute NaOH to remove dissolved boron trifluoride. The product, 2,5-dimethoxyfluorobenzene, was a fluid, straw-colored oil that weighed 7.0 g. 

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