Phosphonous acids reactions

Enol ethers from (2-oxoalkyl)phosphonic diesters are themselves highly reactive in hydrolysis and addition reactions. (2-Butoxyethenyl)phosphonic dichloride in CCI4 solution readily adds bromine in the cold, but attempts to distil the resultant (1,2-dibro-mo-2-butoxyethyl)phosphonic dichloride result in dehydrobromination the product 334 is unreactive to further attempted bromination, but suffers ready hydrolysis to (1-hydroxy-2-oxoethyl)phosphonic acid, and similarly, hydrolysis of the precursor dichloride yields (2-oxoethyl)phosphonic acid. Reactions between enol ethers and amides, carbamates or phosphoramidates, under acidic conditions, yield the enamides 335 [R = CO-alkyl, CO-aryl, COO-alkyl or P(0)(0Pr%f (2-Alkoxyethenyl)phosphonic diisocyanates act as precursors to phosphapyrimidines 336 and analogous phosphapurines ... 

Albrite 150. See 2-Ethylhexyl phosphate Albrite 300. See Phosphonic acid, reaction prods, with maleic anhydride, sodium salts Albrite Acetic Acid 80%. See Acetic acid Albrite Amyl Acid Phosphate. See Amyl acid phosphate... 

Phosphonic acid, reaction prods, with maleic anhydride, sodium saits 181314-48-7... 

This reaction is catalyzed by hydrogen chloride and yields can be essentially quantitative when using either free phosphonic acid or its diesters. The flame retardant, Eyrol 6, produced by Akzo Chemicals, Inc. and used for rigid urethane foams, is synthesized as follows (24). 

The reaction of phosphoms trichloride and water is highly exothermic and vigorous. Depending on the mole ratio of H2O/PCl, three different products can result from hydrolysis. If the ratio is greater than 3, phosphonic acid is produced ... 

Uses. The largest usage of PCl is to produce phosphonic acid, H PO, which in reaction with iminodiacetic acid and formaldehyde forms a glyphosate intermediate that is decarboxymethylated to glyphosate, an effective nonselective herbicide (see Herbicides). Phosphoms trichloride is also a convenient chlorinating reagent for producing various acyl and alkyl chlorides. 

All phosphoms oxides are obtained by direct oxidation of phosphoms, but only phosphoms(V) oxide is produced commercially. This is in part because of the stabiUty of phosphoms pentoxide and the tendency for the intermediate oxidation states to undergo disproportionation to mixtures. Besides the oxides mentioned above, other lower oxides of phosphoms can be formed but which are poorly understood. These are commonly termed lower oxides of phosphoms (LOOPs) and are mixtures of usually water-insoluble, yeUow-to-orange, and poorly characteri2ed polymers (58). LOOPs are often formed as a disproportionation by-product in a number of reactions, eg, in combustion of phosphoms with an inadequate air supply, in hydrolysis of a phosphoms trihahde with less than a stoichiometric amount of water, and in various reactions of phosphoms haUdes or phosphonic acid. LOOPs appear to have a backbone of phosphoms atoms having —OH, =0, and —H pendent groups and is often represented by an approximate formula, (P OH). LOOPs may either hydroly2e slowly, be pyrophoric, or pyroly2e rapidly and yield diphosphine-contaminated phosphine. LOOP can also decompose explosively in the presence of moisture and air near 150° C. 

This reaction can be violent partiy because of the heat Hberated in the solvation of the hydrogen chloride. The hydrolysis can be moderated by adding PCl to a saturated solution of HCI Subsequentiy, the water and hydrogen chloride are boiled until the temperature reaches 180°C. On cooling, phosphonic acid crystallizes from the melt. 

The dimer of phosphonic acid, diphosphonic acid [36465-90-4] (pyrophosphoms acid), H4P2O3, is formed by the reaction of phosphoms trichloride and phosphonic acid in the ratio of 1 5. It is also formed by the thermal decomposition of phosphonic acid. Unlike the chemistry of phosphoric acid, thermal dehydration does not lead to polymers beyond the dimer extended dehydration leads to a disproportionation to condensed forms of phosphoric acid, such as [2466-09-3] and phosphine. 

Monoesters of the phosphonic acids are Httle used in industry. The diesters, 0=PR(0R)2, of phosphonic acid are commonly prepared in industry from trialkyl phosphites in a MichaeUs-Arbusov reaction ... 

Trialkyl esters of phosphonic acid exist ia two structurally isomeric forms. The trialkylphosphites, P(OR)2, are isomers of the more stable phosphonates, 0=PR(0R)2, and the former may be rearranged to resemble the latter with catalytic quantities of alkylating agent. The dialkyl alkylphosphonates are used as flame retardants, plasticizers, and iatermediates. The MichaeUs-Arbusov reaction may be used for a variety of compound types, including mono- and diphosphites having aryl as weU as alkyl substituents (22). Triaryl phosphites do not readily undergo the MichaeUs-Arbusov reaction, although there are a few special cases. 

Multilayers of Diphosphates. One way to find surface reactions that may lead to the formation of SAMs is to look for reactions that result in an insoluble salt. This is the case for phosphate monolayers, based on their highly insoluble salts with tetravalent transition metal ions. In these salts, the phosphates form layer stmctures, one OH group sticking to either side. Thus, replacing the OH with an alkyl chain to form the alkyl phosphonic acid was expected to result in a bilayer stmcture with alkyl chains extending from both sides of the metal phosphate sheet (335). When zirconium (TV) is used the distance between next neighbor alkyl chains is - 0.53 nm, which forces either chain disorder or chain tilt so that VDW attractive interactions can be reestablished. 

Surfactants are prepared which contain carboxylic acid ester or amide chains and terminal acid groups selected from phosphoric acid, carboxymethyl, sulfuric acid, sulfonic acid, and phosphonic acid. These surfactants can be obtained by reaction of phosphoric acid or phosphorus pentoxide with polyhydroxystearic acid or polycaprolactone at 180-190°C under an inert gas. They are useful as polymerization catalysts and as dispersing agents for fuel, diesel, and paraffin oils [69]. 

By substituting n-butyldichlorophosphine for PC13 the butyl monoester of the a-hydroxyalkylphosphonic acid is formed. If there are 12 or more carbon atoms in the molecule the compound will be surface-active and still soluble in water. Alkali salts of the free phosphonic acids obtained by the reactions... 

Reaction of Unsaturated Compounds with Dialkyl Phosphites The diesters of phosphorous acid are somewhat resistant to oxidation and used as intermediates for the reaction with olefins forming phosphonic acids. The reaction takes place in the presence of free radical initiators, such as di-/-bu-tyl peroxide [104,105]. 

Another method for the preparation of hydroxyalkanephosphonic acids is the conversion of aldehydes with dialkyl phosphites in the presence of triethylamine or sodium methylate leading directly to the corresponding a-hydroxyalkane-phosphonates. This reaction is reversible, leading to the starting materials aldehyde and diethyl phosphite again [143,146]. 

Phosphonous acid diesters undergo the Arbusov reaction with a wide variety of organic halides, giving esters of secondary phosphinic acids, as is demonstrated in Eq. (88) ... 

Surfactants which contain carboxylic acid ester or amide chains with terminal phosphonic acid groups are prepared from polyhydroxystearic acid or poly-caprolactone. Such reaction products are useful as dispersants, emulsifiers, and, in some cases, bactericides, disinfectants, and antiseptics see Sec. III.C.9 [69]. 

Various cyclic phosphonate esters 36 and 37 have been described previously as products from the HHT reaction of 25 with the appropriate cyclic phosphite. A complementary method has also been developed from the V-protected phosphonyl chloride 84, which was readily prepared from the corresponding phosphonic acid 83. Subsequent reaction of 84 with the appropriate diol produced the cyclic phosphonate esters 85 (63). Higher homologs of 85 have also been prepared from the analogous propane or butane diols. 

Other cyclizations at phosphorus have been observed when certain phosphinates were used in the acid-catalyzed Mannich reaction. As observed previously with various phosphonous acid derivatives, reaction of aliphatic phosphinic acids with primary amines favored the formation of 2 1 adducts (73). Thus, glycine and other a-amino acids reacted under the typical conditions with excess formaldehyde and alkyl phosphonous acids to give the bis-phosphinylmethyl adducts 125. 

Note Substances that form more stable colorless complexes with the metal ions (eg. EDTA, phosphates, phosphonic acids ete) than thiocyanate interfere with the reaction. 

Other interesting examples of proteases that exhibit promiscuous behavior are proline dipeptidase from Alteromonas sp. JD6.5, whose original activity is to cleave a dipeptide bond with a prolyl residue at the carboxy terminus [121, 122] and aminopeptidase P (AMPP) from E. coli, which is a prohne-specific peptidase that catalyzes the hydrolysis of N-terminal peptide bonds containing a proline residue [123, 124]. Both enzymes exhibit phosphotriesterase activity. This means that they are capable of catalyzing the reaction that does not exist in nature. It is of particular importance, since they can hydrolyze unnatural substrates - triesters of phosphoric acid and diesters of phosphonic acids - such as organophosphorus pesticides or organophosphoms warfare agents (Scheme 5.25) [125]. 

Trimethylsilyl esters of tris(thio)phosphonic acids 2070 are readily oxidized by DMSO in toluene at -30 °C to give the dimeric tetra(thia)diaphosphorinanes 2071 and HMDSO 7 [208] (cf. also the oxidation of silylated thiophenol via 2055 to diphenyl disulfide). The polymeric Se02 is depolymerized and activated by reaction with trimethylsilyl polyphosphate 195 to give the corresponding modified polymer... 

B. Reactions.—(/) Nucleophilic Attack at Phosphorus. A reinvestigation of the reaction between phosphorus trichloride and t-butylbenzene in the presence of aluminium chloride has shown that the product after hydrolysis is the substituted phosphinic acid (11), and not the expected phosphonic acid (12). Bis(A-alkylamino)phosphines have been reported to attack chlorodiphenyl phosphine with nitrogen, in the presence of a base, to give bis-(A-alkyl-A-diphenylphosphinoamino)phenylphosphines (13). In (13), the terminal phosphorus atoms are more reactive than the central one towards sulphur and towards alkyl halides. 

Two preparations of diesters of phosphonous acid have been reported, - One of these, which claims to be the first preparation of these derivatives, involves the reaction of ammonium hypophosphite with triaikylsilylamines to give bis(trialkylsilyl) esters (127) in excellent yield. These compounds are extremely reactive, e.g. they are spontaneously inflammable in air. Dialkyl phosphonites (128) have also been prepared by the reduction of... 

A. Synthetic Methods.—Electrophilic addition of P compounds to olefinic compounds is a well-established route to phosphonic acids, although yields are often disappointing. With phosphorus pentachloride it has been found that yields are greatly improved when phosphorus trichloride is added to the reaction mixture. Since the orientation of the addition implies that electrophilic addition to phosphorus rather than chlorine is the initial step, it seems likely that the trihalide participates by decreasing the free concentration of chlorine rather than by a more active role. This... 

---