Phosphorous compounds oxidation

The use of silver (II) salts, particularly argentic picolinate, as reagents for hydroxyl oxidation has also been disclosed recently. The reaction may be run in acid, neutral or basic media in aqueous or polar organic solvents at room or slightly elevated temperatures. Primary alcohols may be oxidized to aldehydes or acids depending on the conditions used. Amines and trivalent phosphorous compounds are more sensitive to oxidation with this reagent than are hydroxyl groups. 

Phosphine-oxide-containing polymers, 345 Phosphorous compounds, as activating agents, 78-79... 

Other phosphorous compounds, as shown in Table 8, were resolved by the same procedure. The three isomeric phosphinates 27b-d containing a methyl group attached to the aryl substituent could also be resolved, irrespective of the methyl position. From the related phosphine oxides 28a d, however, only those with R=H (28a) and R=m-CH (28c) could be well resolved no satisfactory resolution could be obtained for the other isomers of 28. The efficiency of the optical resolution of alkylaryl-substituted sulfoxides and selenoxides was found to depend similarly on the type of substitution on the aryl ring. 

Secondary anti-oxidants. These compounds react with the hydroperoxide and peroxide intermediates. They are usually di-valent sulfur or tri-valent phosphorous compounds ... 

In recent years, modification of zeolites, such as HZSM-5, by phosphoric compounds or metal oxides has been extensively studied, but little information is available on the modification of zeolites by diazomethane, which is an excellent methylating agent for protonic acidic sites. It is capable of entering into the small pores of zeolites because of its small molecular size and linear molecular structure. Yin and Peng (1,2) reported that the acidity and specific surface area of the inorganic oxide supports (AljOs, SiOj) and zeolite catalysts... 

Oxygen-dominant phosphors are generally produced by solid-state reactions in which the components of the phosphor (mostly oxides) are intimately mixed and fired at 500-1500 °C. The desired phosphor is formed by solid-state reaction below the melting point of the compound during a firing period of 3-16 h. 

Several phosphorous compounds having a P=S bond are also catalysts for this reaction. For example, heating of phenyl isocyanate with triphenylphosphine sulfide at 160 °C affords diphenylcarbodiimide. Since triphenylphosphine sulfide was recovered unchanged, a different mechanism seems to be operative. A tricyclic P S compound, S=P[N(Me)CH2CH2l3N, also catalyzes the transformation of isocyanates to carbodiimides. Triphenylarsine oxide and triphenylantimony oxide also catalyze the conversion of isocyanates into carbodiimides. The catalytic activity of the oxides of phosphorous, arsenic and antimony are in agreement with the dipole moments of... 

Environment, toxicity With durable flame retardancy, formaldehyde emission during curing and after finishing, phosphorous compounds in the waste water Antimony oxide and organic halogen donators (DBDPO and HCBC) are discussed as problems (for example possibility of generating polyhalo-genated dioxins and furanes)... 

Common flame retardants are aluminum trihydrate, brominated compounds, phosphorous compounds, antimony oxide, chlorinated compounds, and boron compounds. Brominated flame retardants are preferred for thermoplastic resins such as polystyrene, polyesters, polyolefins and polyamides but are also used in epoxies, ABS and polycarbonates. Decabromodiphenyl oxide is the most common brominated flame retardant used. 

Floiiu- l tardantS i g inhibit pvroivsis or oxidation reactions during combustion phosphorous compounds, halogen i-agents, antimony r- jpxide especially used in the field of construction... 

Oxide phosphors arc attractive as the key materials for the generation of white light with blue LEDs. Many phosphor compounds can be an adoptable host lattice with strong absorption and high quantum efficiency. According to their variable composition, oxide phosphors are divided into the followings categories ... 

Antioxidants are either ma terials that themselves are readily oxidized or that form a stable product by con bining with a polymer that is oxidizing. Chemical groupings used as antioxidan s include phosphorous compounds, cadmium and nickel compounds, aromatic imines, products of amines or aminophenols with a variety of compounds (ketc nes, aldehydes), and phenols. 

A mixture of acid hydrazide (1 1 mmol), acyl chloride (2 1.3 mmol), and phosphorous pent-oxide (5 mmol) dissolved in acetonitrile (10 mL) was stirred at room temperature for 10-15 min to complete the reaction (as indicated by TLC). The solvent was then removed under vacuo and the mixture was dissolved in dichloromethane and washed with water (3 x 50 mL). The organic layer was then dried over sodium sulfate and evaporated under vacuo. The solid precipitates were further recrystallized from ethanol to afford pure 2,5-di-substituted 1,3,4-oxadiazoles (3) in good yields. The products were characterized by comparison of their spectral and physical data with those of known compounds reported in the literature. 

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