Commercial Polyphosphoric Acid

This acid, which usually contains more P2O5 than superphosphoric acid, but less than that required by the metaphosphate composition, is used industrially for its dehydrating and catalytic properties. For some applications it has to be somewhat purer than superphosphoric acid (Chapter 12.18). The acid is available as glassy lumpy material which is sometimes termed metaphosphoric acid . 

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The solidification temperature of commerdal superphosphoric acid is lower than that of 100% H3PO4 and about the same as that of 85% H3PO4. It can usually be transported and handled as a liquid above about 18°C. Superphosphoric and commercial polyphosphoric acids (see below) are more economic to handle than the less concentrated varieties. The main use of superphosphoric acid is in the production of fertilisers (Chapter 12.2). 

Phosphoric acid is a considerably weaker acid than H2SO4 at comparable concentrations. Even commercial polyphosphoric acid (73% P2O6, 27% H2O) does not attain the levels of protonating power of 96% H2SO4 (Table III), although its low activity of H2O promotes conversions of the B.OH to R+ type (Deno et al., 1962a). 

A number of commercial phosphoms-containing polyols have been made by the reaction of propylene oxide and phosphoric or polyphosphoric acid. Some have seen commercial use but tend to have hydrolytic stabiHty limitations and are relatively low in phosphoms content. BASF s Pluracol 684 is a high functionahty polyol containing 4.5% P, sold for Class 11 rigid foam use. 

Commercial condensed phosphoric acids are mixtures of linear polyphosphoric acids made by the thermal process either direcdy or as a by-product of heat recovery. Wet-process acid may also be concentrated to - 70% P2O5 by evaporation. Liaear phosphoric acids are strongly hygroscopic and undergo viscosity changes and hydrolysis to less complex forms when exposed to moist air. Upon dissolution ia excess water, hydrolytic degradation to phosphoric acid occurs the hydrolysis rate is highly temperature-dependent. At 25°C, the half-life for the formation of phosphoric acid from the condensed forms is several days, whereas at 100°C the half-life is a matter of minutes. 

Prepare 6-methoxy-l-indanone (I) (JCS 1986(1962)) using polyphosphoric acid made by diluting 500 g of the commercial acid with 120 g 85% phosphoric acid. 2.5 g (I) in 176 ml ether and reflux one hour with 0.27 g lithium aluminum hydride. Cool and carefully add water and filter when bubbling stops (can use Celite filter aid). Dry and evaporate in vacuum and store twelve hours at -15° (under N2 if possible) to precipitate the white 6-methoxy-l-indanol (II) (recrystallize-n-hexane). 2.5 g (II) in 73 ml benzene and reflux one-half hour with 0.2 g p-toluenesulfonic acid. Cool, add water and separate the phases. Extract the aqueous phase with ether and combine with benzene phase and dry, evaporate in vacuum to get 5-methoxy-indene (III) (can distill 110-45/10). 1.53 g (III) and 1.39 g N.N-diethyl-aminoethyl-Cl.HCI in benzene (prepare the free base in benzene as described previously). Reflux four hours with 0.42 g sodamide, cool, wash with water and dry, evaporate in vacuum to get the indene analog of 6-methoxy DET as a dark liquid (can crystallize as oxalate). Alternatively, dissolve 2.51 g (III) in ether and treat (under N if possible) with 12 ml 1.6M buty-Li in hexane at 0-10°. After two hours cool to -30° and add 12 ml more of butyl-Li. Add ether suspension of 2.5 g N,N-diethylaminoethyl-CI. HCI over one-half hour and warm to room temperature. Filter, evaporate in vacuum to get the 6-methoxy-DET analog. 

Alkylation. Friedel-Crafts alkylation (qv) of benzene with ethylene or propylene to produce ethylbenzene [100-41 -4], CgH10, or isopropylbenzene [98-82-8], C9H12 (cumene) is readily accomplished in the liquid or vapor phase with various catalysts such as BF3 (22), aluminum chloride, or supported polyphosphoric acid. The oldest method of alkylation employs the liquid-phase reaction of benzene with anhydrous aluminum chloride and ethylene (23). Ethylbenzene is produced commercially almost entirely for styrene manufacture. Cumene [98-82-8] is catalytically oxidized to cumene hydroperoxide, which is used to manufacture phenol and acetone. Benzene is also alkylated with C1Q—C20 linear alkenes to produce linear alkyl aromatics. Sulfonation of these compounds produces linear alkane sulfonates (LAS) which are used as biodegradable deteigents. 

Cyclodehydration. The commercial preparation of an antihistamine (Lorata-dine, 3) requires cyclodehydration of the ketone 1. Use of the usual reagent for this reaction, polyphosphoric acid at 190°, leads to a mixture of two products in about 45% yield. The most useful and reasonably priced reagent is HF and BF3 at -30°, which gives 2 in >90% yield. 

Diborane can be prepared by a variety of methods, the most common being the reduction of boron trihalides with active metal hydrides - and the reaction of hydroborate salts with boron trifluoride, tin(II) chloride, sulfuric acid, methane-sulfonic acid, orthophosphoric acid, or polyphosphoric acid. Although diborane is commercially available in bulk quantities, we have found the reaction of potassium hydroborate, KBH4, with 85% orthophosphoric acid to be convenient for the rapid preparation in a vacuum line of small quantities of this material. ... 

BACs can be activated toward Friedel-Crafts acylation with commercially available catalyst Envirocat EPIC . The catalyst is constituted by a natural clay impregnated with polyphosphoric acid. The reaction occurs... 

To 45 g (0.312 mol) of anhydrous trans- 1,4-cyclohexanedimethanol and 0.05 g polyphosphoric acid in a commercially available polymerization reactor is added, with constant stirring under an inert nitrogen environment and normal atmospheric pressure, 50 g (0.312 mol) of anhydrous 2,2-diethoxytetrahydro-furan. Next, the mixture is heated to 110-115°C and held at that temperature for 1.5 to 2h with slow distillation of ethanol. Then, while maintaining the temperature, the pressure is gradually reduced to 0.01 mm of mercury and at this reduced pressure the temperature is slowly increased to 180 °C. The reaction is continued at this temperature for 24 h. The polymer is isolated by extrusion from the reactor. 

Another procedure for preparation of valuable heterocyclic scaffolds involves the Biginelli condensation on a PEG Support [75, 76]. Polymer-bound acetoacetate was prepared by reacting commercially available PEG 4000 with 2,2,6-trimethyl-4H-l,3-dioxin-4-one in toluene under reflux (Scheme 16.52). The microwave-assisted cyclocondensation was performed with nonvolatile polyphosphoric acid (PPA) as a catalyst in a domestic microwave oven [76]. During microwave heating the PEG-bound substrate melted, ensuring a homogeneous reaction mixture. After the reaction diethyl ether was added to precipitate the polymer bound products. The desired compounds were released by treatment with sodium methoxide in methanol at room temperature. All dihydropyrimidines were obtained in high yield purification was achieved by recrystallization from ethanol. 

Creatinol-O-phosphate can be prepared from partially hydrolysed phos-phoryl chloride and creatinol hydrobromide at room temperature [77]. Alternatively, thermal dehydration of creatinol phosphate (74) under reduced pressure gives creatinolfosfate (75) Scheme 5.18.) [77, 78]. A commercial procedure employs polyphosphoric acid in this method [79]. The drug is stable in aqueous solution at room temperature, but its isomer creatinol-A-phosphate hydrolyses rapidly to creatinol [77]. Creatinolfosfate has anti-ischaemic and antiarrhythmic properties and gives an improved ionic balance and a stronger heart beat [80]. It is useful in the clinical treatment of cardiac insufficiency and rhythm and conduction disturbances [81]. 

Commercial PBI is a proprietary product (Celanese) made from 3,3, 4,4 -tetra aminobiphenyl (TAB) and diphenyl isophtalate in a two step, melt/solid polymerization [190]. A modified PBI structure such as poly(2,5)-benzimidazole (ABPBI) (see Fig. 6.10) has been synthesized by condensation of 3,4-diaminobenzoic acid (DABA) monomer in polyphosphoric acid [191]. 

Solid pyrophosphoric acid is obtainable only by the spontaneous crystallization of a polyphosphoric acid mixture containing 79.8 0.2 per cent phosphorus(V) oxide. Such a liquid polyphosphoric acid may be prepared (1) by dehydration of 85 per cent orthophosphoric acid, (2) by dissolving phosphorus(V) oxide in 85 per cent orthophosphoric acid, (3) by adding water to commercial tetraphos-phoric acid, or (4) by allowing phosphorus(V) oxychloride to react with 85 per cent phosphoric acid. The first three of these procedures are preferred. 

GB started commercial manufacture of white P from bones Concluded phosphate of lime was the important nutrient in bones Condensed polyphosphoric acids prepared P-containing Lecithin first isolated from egg yolk Phosphate rock first mined in Suffolk, England Discovered thiophosphoric esta-s Inosinic acid isolated from beef muscle Existence of trimethylphosphine, PMe, reported First preparation of red phosphorus... 

Thieno[2,3-f>]thiophene is readily prepared from commercially available 2-thiophenethiol (Scheme 17.4) [79], Alkylation with bromoacetaldehyde dimethyl acetal proceeds in quantitative yield. Deprotection and ring closure occur in one pot in the presence of polyphosphoric acid (PPA) in refluxing chlorobenzene to afford the product as a colorless oil. Alkyl groups can readily be introduced into the 3-position by alkylation of 2-thiophenethiol with a chloro ketone, such as l-chlorodecan-2-one. Ring closure again occurs in the presence of polyphosphoric acid to afford the 3-alkylated monomers [80],... 

Commercial SCR V205,W03/Ti02 Cu-ZSM zeolites Simulated flue gas N0,02,H20,NH3/N2 NO/Ar Deactivation of active V sites by covering with polyphosphoric acids Activity of Cu + sites depending on their location within the pore structure 42 43... 

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