Phosphorus basicity

Kroshefsky, R. D., Verkade, J. G. Staudinger reactions of aminophosphines. Influence of phosphorus basicity. Inorg. Chem. 1975, 14, 3090-3095. 

This can be extracted from impure phosphine prepared by the action of sodium hydroxide on phosphorus. Unlike hydrazine, it has no basic properties. It is a powerful reducing agent and burns spontaneously in air, this reaction explaining why impure phosphine containing traces of diphosphane ignites spontaneously in air. 

Nitrogen is unusual in forming so many oxides. The acidity of the Group V oxides falls from phosphorus, whose oxides are acidic, through arsenic and antimony whose oxides are amphoteric, to the basic oxide ofbismuth. This change is in accordance with the change from the non-metallic element, phosphorus, to the essentially metallic element, bismuth. The +5 oxides are found, in each case, to be more acidic than the corresponding + 3 oxides. 

USING OF THE MICELLAR MEDIUM, BASIC DYES AND PRECONCENTRATION ON THE POLYURETHANE FOAMS FOR THE DETERMINATION OF PHOSPHORUS AND ARSENIC... 

Other limitations on phytoplankton growth are chemical in nature. Nitrogen, in the form of nitrate, nitrite and ammonium ions, forms a basic building material of a plankton s cells. In some species silicon, as silicate, takes on this role. Phosphorus, in the form of phosphate, is in both cell walls and DNA. Iron, in the form of Fe(III) hydroxyl species, is an important trace element. Extensive areas of the mixed layer of the upper ocean have low nitrate and phosphate levels during... 

JOM(400)149 96BSCF33]. The complex 164 is the first known t] -phospholyl species. The tungsten atoms have a coordination number of 9, and the carbon atoms of the phospholyl ring are coplanar. The phosphorus atom deviates from the plane of carbon atoms by 0.015 nm. The basic difference between the Ti -cyclopentadienyl and ri -phospholyl complexes is the existence of a low-lying LUMO localized mainly at the phosphorus atom. 

A mixture of 10 g of the above piperazine carboxylate ester, 8 g of phosphorus pentoxide and 20 ml of phosphorus oxychloride is heated under reflux for about 1 day, diluted with 100 ml each of chloroform and benzene and quenched with 200 g of ice. The mixture is made basic with 10% sodium hydroxide. Theorganic layer is Isolated and extracted with 150 ml of dilute hydrochloric acid. The product is precipitated from the aqueous layer by addition of 10% sodium hydroxide, extracted with benzene and dried over potassium carbonate. Recrystallization from benzene-petroleum ether gives 2[Pg.77]

The mixture is taken up with water and the base is extracted from the toluene with dilute hydrochloric acid. The hydrochloric solution is rendered alkaline with caustic soda, the base is separated with ether, dried, and after distillation of the ether fractionated in vacuo, BP at 0.05 mm Hg, 150° to 153°C. The basic ether is then dissolved in dry ether, and ether saturated with dry hydrogen chloride is added dropwise with stirring. An excess of hydrogen chloride must be avoided as it may produce decomposition to the corresponding diphenyl ethylene. The ether-moist hydrochloride is preferably dried at once in vacuo and subsequently reprecipitated from acetone-ether and then again dried in vacuo over phosphorus pentoxide. Hydrochloride, MP 12B°C. 

The reaction mixture was poured into 25 ml of water and the mixture made strongly basic with ION sodium hydroxide solution. The mixture was extracted 3 times with 50 ml portions of benzene, the combined extracts washed with water and concentrated to a volume of approximately 50 ml. The solution was saturated with dry hydrogen chloride and the white crystalline product collected and dried. The yield of product, MP 251.6° to 252.6°C (dec.) was 2.5 g. Recrystallization from a mixture of absolute alcohol and absolute ether gave a product, MP 252.6° to 253.6°C. A sample was analyzed after drying for 7 hours at 110°C over phosphorus pentoxide in vacuo. 

A mixture of 4-methyl-2 -(p-chlorophenoxy)-1-piperazinecarboxanilide hydrochloride (6 g), 50 ml of phosphorus oxychloride and 10 g of phosphorus pentoxide is heated under reflux for about 24 hours, and then concentrated to a gummy residue by evaporation under reduced pressure. This residue is taken up in 150 ml of ether, 200 g of ice is added, and the mixture is made basic with concentrated aqueous ammonium hydroxide. The ether layer is separated, dried over potassium hydroxide pellets and evaporated to a solid residue (approximately 4 g). 

This crude product is dissolved in 100 ml of dilute hydrochloric acid, the acid solution is extracted with ether, and the aqueous layer is made basic with sodium hydroxide solution (3N) in the presence of ether (approximately 250 ml). The ether layer Is separated, dried over potassium hydroxide and evaporated to a white solid. Additional purification by repeating the formation of the hydrochloric acid salt and reprecipitation of the base is carried out. When purified in this manner, followed by drying at 80°C in vacuo over phosphorus pentoxide, 2-chloro-11-(4-methyl-1-piperazinyl)dibenz[b,f] [1,4]oxazepine, li/IP 109° to 111°C, is obtained. 

As well as phosphorus ligands, heterocyclic carbenes ligands 10 have proven to be interesting donor ligands for stabilization of transition metal complexes (especially palladium) in ionic liquids. The imidazolium cation is usually presumed to be a simple inert component of the solvent system. However, the proton on the carbon atom at position 2 in the imidazolium is acidic and this carbon atom can be depro-tonated by, for example, basic ligands of the metal complex, to form carbenes (Scheme 5.3-2). 

The grades with the 410 or 420 numerals are the basic 13% chromium type with varied carbon content. The additions of sulphur or selenium (possibly with phosphorus) to some grades (416 group) is to improve machinability. 431S29 has increased chromium content to improve corrosion resistance, but reference to Fig. 3.11 shows that such addition alone would lead to a mixed martensite-5-ferrite structure with certain disadvantages to mechanical properties. The nickel addition is to limit ferrite content. 

A wide range of applications for hard, wear-resistant coatings of electroless nickel containing silicon carbide particles have been discussed by Weissenberger . The solution is basically for nickel-phosphorus coatings, but contains an addition of 5-15 g/1 silicon carbide. Hiibner and Ostermann have published a comparison between electroless nickel-silicon carbide, electrodeposited nickel-silicon carbide, and hard chromium engineering coatings. 

To circumvent the need for strong acid and allow the dehydration of secondary alcohols, reagents have been developed that are effective under mild, basic conditions. One such reagent, phosphorus oxychloride (POCI3) in the basic amine solvent pyridine, is often able to effect the dehydration of secondary and tertiary alcohols at 0 °C. 

The impure iron is made into steel by burning out most of the carbon, sulfur, and phosphorus. Today there are three common furnace types for making steel—the open-hearth furnace (85% of U.S. production), the electric arc furnace (10%), and the Bessemer converter (5%). These furnaces differ in construction but the chemistry is basically similar. 

The deoxygeneration of nitroarenes by trivalent phosphorus compounds in the presence of amines is a useful route to 3/f-azepin-2-amines (cf. compounds 32, Section 3.1.1.4.2.2.). Subsequently, it has been shown, by carrying out the reaction in strongly basic solution, that the process can be extended to the synthesis of 1H-. 3H- and 5//-2-benzazepines from nitronaph-thalenes 43 For example, 1-nitronaphthalenes 3 with dimethyl phosphite in the presence of sodium methoxide and a primary or secondary aliphatic amine, yield the dimethyl 5//-2-ben-zazepin-3-yl phosphonates 4 accompanied, in some cases, by the isomeric 3//-2-bcnzazepin-3-yl phosphonates 5. 

S-Alkylation of 9-methoxy-5//-pyrido[3.2-e]azcpine-7(6//)-thione (10), prepared from the pyridoazepin-7-one 9 with phosphorus pentasulfide in pyridine, is achieved to give 11 in high yield with iodomethane in basic solution.191... 

Previous syntheses of terminal alkynes from aldehydes employed Wittig methodology with phosphonium ylides and phosphonates. 6 7 The DuPont procedure circumvents the use of phosphorus compounds by using lithiated dichloromethane as the source of the terminal carbon. The intermediate lithioalkyne 4 can be quenched with water to provide the terminal alkyne or with various electrophiles, as in the present case, to yield propargylic alcohols, alkynylsilanes, or internal alkynes. Enantioenriched terminal alkynylcarbinols can also be prepared from allylic alcohols by Sharpless epoxidation and subsequent basic elimination of the derived chloro- or bromomethyl epoxide (eq 5). A related method entails Sharpless asymmetric dihydroxylation of an allylic chloride and base treatment of the acetonide derivative.8 In these approaches the product and starting material contain the same number of carbons. 

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