Phosphoric Acid Esters Research Articles

Modeling the hydrolysis of perfluorinated compounds containing carboxylic and phosphoric acid ester functions and sulfonamide groups

Temperature-dependent rate constants were estimated for the acid- and base-catalyzed and neutral hydrolysis reactions of perfluorinated telomer acrylates (FTAcrs) and phosphate esters (FTPEs), and the SN1 and SN2 hydrolysis reactions of fluorotelomer iodides (FTIs). Under some environmental conditions, hydrolysis of monomeric FTAcrs could be rapid (half-lives of several years in marine systems and as low as several days in some landfills) and represent a dominant portion of their overall degradation. Abiotic hydrolysis of monomeric FTAcrs may be a significant contributor to current environmental loadings of fluorotelomer alcohols (FTOHs) and perfluoroalkyl carboxylic acids (PFCAs). Polymeric FTAcrs are expected to be hydrolyzed more slowly, with estimated half-lives in soil and natural waters ranging between several centuries to several millenia absent additional surface area limitations on reactivity. Poor agreement was found between the limited experimental data on FTPE hydrolysis and computational estimates, requiring more detailed experimental data before any further modeling can occur on these compounds or their perfluoroalkyl sulfonamidoethanol phosphate ester (PFSamPE) analogs. FTIs are expected to have hydrolytic half-lives of about 130 days in most natural waters, suggesting they may be contributing to substantial FTOH and PFCA inputs in aquatic systems. Perfluoroalkyl sulfonamides (PFSams) appear unlikely to undergo abiotic hydrolysis at the S-N, C-S, or N-C linkages under environmentally relevant conditions, although potentially facile S-N hydrolysis via intramolecular catalysis by ethanol and acetic acid amide substituents warrants further investigation.

Noncovalent Synthesis of Hierarchical Zinc Phosphates from a Single Zn4O12P4 Double‐Four‐Ring Building Block: Dimensionality Control through the Choice of Auxiliary Ligands

In contrast to the well-known reaction of phosphonic acids RP(O)(OH)(2) with divalent transition-metal ions that yields layered metal phosphonates [RPO(3)M(H(2)O)](n), the 2,6-diisopropylphenyl ester of phosphoric acid, dippH(2), reacts with zinc acetate in methanol under ambient conditions to afford tetrameric zinc phosphate [(ArO)PO(3)Zn(MeOH)](4) (1). The coordinated methanol in 1 can be readily exchanged by stronger Lewis basic ligands at room temperature. This strategy opens up a new avenue for building double-four-ring (D4R) cubane-based supramolecular assemblies through strong intercubane hydrogen-bonding interactions. Seventeen pyridinic ligands have been used to synthesize as many D4R cubanes [(ArO)PO(3)Zn(L)](4) (2-18) from 1. The ligands have been chosen in such a way that the majority of them contain an additional functional group that could be used for noncovalent synthesis of extended structures. When the ligand does not contain any other hydrogen-bonding donor-acceptor sites (e.g., 2,4,6-trimethylpyridine (collidine)), zero-dimensional D4R cubanes have been obtained. The use of pyridine, lutidine, 2-aminopyridine, and 2,6-diaminopyridine, however, results in the formation of linear or zigzag one-dimensional assemblies of D4R cubanes through strong intermolecular C-H...O or N-H...O interactions. Construction of two-dimensional assemblies of zinc phosphates has been achieved by employing 2-hydroxypyridine or 2-methylimidazole as the exo-cubane ligand on zinc centers. The introduction of an alcohol side chain on the pyridinic ligand in such a way that the -CH(2)OH group cannot participate in intracubane hydrogen bonding (e.g., pyridine-3-methanol, pyridine-4-methanol, and 3,5-dimethylpyrazole-N-ethanol) leads to the facile noncovalent synthesis of three-dimensional framework structures. Apart from being useful as building blocks for noncovalent synthesis of zeolite-like materials, compounds 1-18 can also be thermolyzed at approximately 500 degrees C to yield high-purity zinc pyrophosphate (Zn(2)P(2)O(7)) ceramic material.

Combination treatment of tribochemical treatment and phosphoric acid ester monomer of zirconia ceramics enhances the bonding durability of resin-based luting cements

The aim of the present study was to evaluate the bonding durability of resin-based luting cement to partially stabilized tetragonal zirconia (Y-TZP) achieved by combination treatment of tribochemical (TBC) treatment and two different phosphate acid ester monomers. Two phosphate acid ester monomers (EP: Epricord opaque primer, AZ: AZ primer) were applied to each surface modification followed by application of resin-based luting cement (Rely-X ARC). Bonding specimens were placed in deionized water at 37 degrees C and stored for 24 h. The other groups were subjected to 30,000 cycles of a thermal stress for the durability test. Shear bond tests were done using a universal testing machine at 1 mm/min. Shear bond strengths of combination treatments using EP and AZ on TBC treatment after thermal stress showed no significant difference (p>0.05) compared with those of storage after 24 h. Combination treatment using phosphoric acid ester monomer could achieve a durable bond.

Preparation and properties of a new composite of epoxy emulsion (EEM) modified cement

High performance cement based composite materials was prepared by adding epoxy emulsion. The epoxy emulsion was synthesized with epoxy phosphoric acid ester and poly-glycol in laboratory. This epoxy emulsion has advantages over other emulsion, such as dehydrated slightly, and, well film formation abilities. The mechanical properties corruptness resistance and structure of epoxy emulsion modified cement mortars were studied. Experimental results show that the mechanical properties of modified cement mortars are slightly increased with increasing epoxy emulsion content, especially the flexure strength. The corruptness resistance of all modified mortars is better than the unmodified mortar. The polymer film forms the bridge phases between the matrix and the aggregate regions, and forms a three-dimension structure in the cement hydration system, which improves the mechanical properties of modified mortars.

Quantification of two urinary metabolites of organophosphorus flame retardants by solid-phase extraction and gas chromatography–tandem mass spectrometry

Trialkyl esters of phosphoric acid are widely used as flame retardants. The corresponding dialkylphosphates are formed as the main metabolites in animal experiments. We extended a previously published method for the determination of four organophosphorus flame retardant metabolites [bis(2-chloroethyl) phosphate, diphenyl phosphate, di-m-cresyl phosphate and di-p-cresyl phosphate] to be able to determine di-n-butyl phosphate (DBP) and bis(2-chloropropyl) phosphate (BCPP) in human urine samples additionally in one run. After solid-phase extraction, derivatization with pentafluorobenzyl bromide and further solid-phase cleanup, the extracts were analysed by gas chromatography-tandem mass spectrometry. The limits of detection were 0.25 microg/l for both analytes. Interday imprecisions were 2-6%. To show the applicability of the method, the internal burden of 25 persons of the population was determined. Twelve percent of the urine samples analysed tested positive for BCPP at concentrations from below the limit of detection to 0.85 microg/l; one sample contained 0.26 microg/l DBP.

Modeling the hydrolysis of perfluorinated compounds containing carboxylic and phosphoric acid ester functions, alkyl iodides, and sulfonamide groups

AbstractTemperature dependent rate constants were estimated for the acid- and base-catalyzed and neutral hydrolysis reactions of perfluorinated telomer acrylates (FTAcrs) and phosphate esters (FTPEs), and the SN1 and SN2 hydrolysis reactions of fluorotelomer iodides (FTIs). Under some environmental conditions, hydrolysis of monomeric FTAcrs could be rapid (half-lives of several years in marine systems and as low as several days in some landfills) and represent a dominant portion of their overall degradation. Abiotic hydrolysis of monomeric FTAcrs may be a significant contributor to current environmental loadings of fluorotelomer alcohols (FTOHs) and perfluoroalkyl carboxylic acids (PFCAs). Polymeric FTAcrs are expected to be hydrolyzed more slowly, with estimated half-lives in soil and natural waters ranging between several centuries to several millenia absent additional surface area limitations on reactivity. Poor agreement was found between the limited experimental data on FTPE hydrolysis and computational estimates, requiring more detailed experimental data before any further modeling can occur on these compounds or their perfluoroalkyl sulfonamidoethanol phosphate ester (PFSamPE) analogs. FTIs are expected to have hydrolytic half-lives of about 130 days in most natural waters, suggesting they may be contributing to substantial FTOH and PFCA inputs in aquatic systems. Perfluoroalkyl sulfonamides (PFSams) appear unlikely to undergo abiotic hydrolysis at the S-N, C-S, or N-C linkages under environmentally relevant conditions, although potentially facile S-N hydrolysis via intramolecular catalysis by ethanol and acetic acid amide substituents warrants further investigation.

Beiträge zur Lebensweise des Ampferblattkäfers (Gastrophysa viridula Deg.)

The habits, injuriousness and control of G. viridula Deg. on Rheum palmatum var. tangutium Rhl. were studied during an outbreak. The beetles and their developmental stages are described and their development recorded. The dock leaf beetle has three generations per year, two in upland areas (1300 m. or above). The female lays from 100 to 600 eggs. The adventitious parthenogenesis known for G. viridula was not observed either outdoors or in the laboratory. The larvae moult twice and are mainly destroyed by Coccinellids, Syrphid larvae and the like. In the main zone of attack, every rhubarb plant had about 6,000 eggs from the females of a single generation. The larvae from these can show losses of up to 50% a few days after hatching. In a given population, the egg mortality is about 1%, larval mortality 80–98% and pupal mortality 1–10%. The total mortality from egg to adult was calculated as 98% for the first generation and 99,9% for the second. The dock leaf beetle was present outdoors from the end of April to the middle of November. The eggs, larvae and pupae still to be found in November, perish. In 1953, the development from egg to adult took 50 days, of which the egg stage needed 7–10 days, the larval stage 21–30 days and the pupal stage 6–9 days. The beetle and its larvae feed mainly on various species of Polygonaceae and prefer Rumex spp. Complete development of G. viridula on Chinese rhubarb, Rheum palmatum var. tangutium Rhl. could be proved, but nowhere was the edible rhubarb observed to be attacked. The larvae are able to feed on several species of other plant families if food is short. In 1953, each generation of the dock leaf beetle destroyed one-sixth of the total leaf area of the Chinese rhubarb. The loss of leaves caused by three generations was tolerated by the rhubarb without measurable decrease in yield. Beetles and larvae can be destroyed by phosphoric acid ester preparations such as E605 dust in one hour and by DDT-lindane or lindane dust preparations in 21/2 hours. G. viridula is liable to mass increases which can be of phytopathological importance because of the polyphytophagy of the larvae for Rumex and rhubarb cultures.

Effect of Double-Tailed Surfactant Architecture on the Conformation, Self-Assembly, and Processing in Polypeptide−Surfactant Complexes

This work describes the solid-state conformational and structural properties of self-assembled polypeptide-surfactant complexes with double-tailed surfactants. Poly(L-lysine) was complexed with three dialkyl esters of phosphoric acid (i.e., phosphodiester surfactants), where the surfactant tail branching and length was varied to tune the supramolecular architecture in a facile way. After complexation with the branched surfactant bis(2-ethylhexyl) phosphate in an aqueous solution, the polypeptide chains adopted an alpha-helical conformation. These rod-like helices self-assembled into cylindrical phases with the amorphous alkyl tails pointing outward. In complexes with dioctyl phosphate and didodecyl phosphate, which have two linear n-octyl or n-dodecyl tails, respectively, the polypeptide formed antiparallel beta-sheets separated by alkyl layers, resulting in well-ordered lamellar self-assemblies. By heating, it was possible to trigger a partial opening of the beta-sheets and disruption of the lamellar phase. After repeated heating/cooling, all of these complexes also showed a glass transition between 37 and 50 degrees C. Organic solvent treatment and plasticization by overstoichiometric amount of surfactant led to structure modification in poly(L-lysine)-dioctyl phosphate complexes, PLL(diC8)(x) (x = 1.0-3.0). Here, the alpha-helical PLL is surrounded by the surfactants and these bottle-brush-like chains self-assemble in a hexagonal cylindrical morphology. As x is increased, the materials are clearly plasticized and the degree of ordering is improved: The stiff alpha-helical backbones in a softened surfactant matrix give rise to thermotropic liquid-crystalline phases. The complexes were examined by Fourier transform infrared spectroscopy, small- and wide-angle X-ray scattering, transmission electron microscopy, differential scanning calorimetry, polarized optical microscopy, and circular dichroism.

Phosphoric acid esters cannot replace polyvinylphosphonic acid as phosphoprotein analogs in biomimetic remineralization of resin-bonded dentin

Polyvinylphosphonic acid (PVPA), a biomimetic analog of phosphoproteins, is crucial for recruiting polyacrylic acid (PAA)-stabilized amorphous calcium phosphate nanoprecursors during biomimetic remineralization of dentin collagen matrices. This study tested the null hypothesis that phosphoric acid esters of methacrylates in dentin adhesives cannot replace PVPA during bimimetic remineralization of resin–dentin interfaces. Human dentin specimens were bonded with: (I) XP Bond, an etch-and-rinse adhesive using moist bonding; (II) XP Bond using dry bonding; (III) Adper Prompt L-Pop, a self-etching adhesive. The control medium contained only set Portland cement and a simulated body fluid (SBF) without any biomimetic analog. Two experimental Portland cement/SBF remineralization media were evaluated: the first contained PAA as the sole biomimetic analog, the second contained PAA and PVPA as dual biomimetic analogs. No remineralization of the resin–dentin interfaces could be identified from specimens immersed in the control medium. After 2–4 months in the first experimental medium, specimens exhibited either no remineralization or large crystal formation within hybrid layers. Only specimens immersed in the second remineralization medium produced nanocrystals that accounted for intrafibrillar remineralization within hybrid layers. The null hypothesis could not be rejected; phosphoric acid esters in dentin adhesives cannot replace PVPA during biomimetic remineralization of adhesive-bonded dentin.

Reactions of stoichiometric intumescent paints

AbstractUnder the influence of heat intumescent paints with stoichiometric compositions decomposed to defined compounds: Ammonium polyphosphate degraded to polyphosphoric acid and ammonia. Polyphosphoric acid reacted with pentaerythritols and glycerol to cyclic phosphoric acid esters, which were identified as the blowing agents. Melamine and polyphosphoric acid combined to melamine polyphosphate and dipolyphosphate. In further degradation of polyphosphoric acid, it dehydrated to phosphorus pentoxide, which reacted with titanium dioxide further to titanium pyrophosphate. Intumescent paints with higher efficiency could be developed by the addition of glycerol, which reacted to phosphoric esters with lower temperatures of decomposition. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Structure-functional analysis of interactions of terminal deoxynucleotidyl transferase with new non-nucleoside substrates

New non-nucleoside esters of phosphoric acid containing various hydrophobic groups, namely (1) N-(2-tripticencarbonyl)-4-aminobutyl; (2) 5-phenylsubstituted N-(2,4-dinitrophenyl)-4-aminobutyl; (3) N-(4-phenylbenzoyl)- and N-(4-(N-benzylamino)benzoyl)-2-aminoethyl groups, as well as (4) diphenylmethyl and fluorenyl groups were synthesized and studied as substrates of terminal deoxynucleotidyl transferase. With the exception of the two latter derivatives, all the analogues displayed substrate properties and could incorporate into the deoxyoligonucleotide 3'-end. As it was shown in biochemical experiments and by computer modeling, a linker joining the triphosphate and hydrophobic fragments of the molecule was necessary for these compounds to display substrate properties.

Expression of esterase gene in yeast for organophosphates biodegradation

Organophosphates are esters of phosphoric acid and can be hydrolyzed and detoxified by carboxylesterase and phosphotriesterase. In this work esterase enzyme (Est5S) was expressed in yeast to demonstrate the organophosphorus hydrolytic activity from a metagenomic library of cow rumen bacteria. The esterase gene ( est5S) is 1098 bp in length, encoding a protein of 366 amino acid residues with a molecular weight of 40 kDa. Est5S enzyme was successfully produced by Pichia pastoris at a high expression level of approximately 4.0 g L −1. With p-nitrophenol butyrate as the substrate, the optimal temperature and pH for enzyme activity were determined to be 40 °C and pH 7.0, respectively. The esterase enzyme was tested for degradation of chlorpyrifos (CP). TLC results obtained inferred that CP could be degraded by esterase enzyme (Est5S) and HPLC results revealed that CP could be efficiently degraded up to 100 ppm. Cadusafos (CS), coumaphos (CM), diazinon (DZ) dyfonate (DF), ethoprophos (EP), fenamiphos (FM), methylparathion (MPT), and parathion (PT) were also degraded up to 68, 60, 80, 40, 45, 60, 95, and 100%, respectively, when used as a substrate with Est5S protein. The results highlight the potential use of this enzyme in the cleanup of contaminated insecticides.

Fluoride-ion-mediated Hydrolysis of Phosphoric Acid Esters, Amides, and Phosphorous Acid Esters Leading to Phosphorofluoridic, Phosphoramide Fluoridic, and Phosphonic Acid Monoester Salts

Abstract Fluoride-ion-promoted hydrolysis of phosphoric acid esters and amides to give phosphorofluoridic and phosphoramide fluoridic acid monoester salts takes place upon treatment with a THF solution of TBAF, whereas a similar treatment of phosphorous acid esters generates phosphonic acid monoester salts selectively without introduction of fluorine.

Supramolecular catalytic systems based on calix[4]resorcinarene for nucleophilic substitution in phosphorous acid esters

The aggregation and catalytic effect in the reaction of hydrolytic decomposition of phosphorous acid esters are studied for series of systems such as calixarene (CA)-sodium dodecyl sulfate (SDS), CA-poly(ethylene imine) (PEI), SDS-PEI, and CA-SDS-PEI. Using dynamic light scattering, sizes of aggregates are determined, cloud point is estimated, and catalytic effect is studied. Data obtained are consistent with the assumption of the joint aggregation in systems studied. The possibility of the passage from 20-fold inhibiting effect to the catalysis (higher than the order of magnitude) of studied reaction by the immobilization of anionic nanoaggregates (nanoreactors) on a catalytically active polymer matrix is demonstrated. The possibility of the passage from microheterogeneous to heterogeneous system and the separation of catalyst from the products are established.

Organic-Soluble Tri-, Tetra-, and Pentanuclear Titanium(IV) Phosphates

Bulky 2,6-disubstituted aryl esters of phosphoric acid, 2,6-dimethylphenyl phosphate (dmppH 2), and 2,6-diisopropylphenyl phosphate (dippH 2) react differently with Cp*TiCl 3 (Cp* = C 5Me 5) under identical reaction conditions. While dippH 2 and Cp*TiCl 3 react in THF at 25 degrees C to yield air-stable trinuclear titanophosphate cage [(Ti 3Cp*Cl(mu 2 -O)(dipp) 2(dippH) 4(THF)].(toluene) ( 1), the similar reaction involving dmppH 2 yields the tetranuclear titanophosphate [Ti 4Cl 2(mu 2 -O) 2(dmpp) 2(dmppH) 6(THF) 2].(toluene) 2 ( 2). Interestingly, the change of titanium source to Ti(O iPr) 4 in the reaction with dippH 2 produces a pentanuclear titanophosphate, [Ti 5(mu 3-O)(O iPr) 6((dipp) 6(THF)] ( 3). Compounds 1- 3 were the only products isolated as single crystals from the respective reaction mixtures in 59, 75, and 54% yield, respectively. The new clusters 1- 3 have been characterized by elemental analysis, IR and NMR ( (1)H and (31)P) spectroscopy, and single crystal X-ray diffraction studies. The structural elucidation reveals that in the reactions leading to 1 and 2, extensive Cp*-Ti bond cleavage occurs, leaving only one residual Cp*-ligand in cluster 1 and none in 2. Closer analysis of the structures of 1- 3 shows common structural features which in turn imply that the formation of all three products could have proceeded via a common Ti-O-Ti dimeric building block.

Cardioprotection with α-tocopheryl phosphate: Amelioration of myocardial ischemia reperfusion injury is linked with its ability to generate a survival signal through Akt activation

The emerging potential of α-tocopheryl phosphate, a phosphoric acid ester of α-tocopherol, in health benefits was tested gavaging this compound (5 mg/kg body wt) to a group of rats for a period of thirty days while the control rats were given water only. After thirty days, the rats were sacrificed, the hearts excised, and the isolated hearts were perfused by working mode. Both control and experimental hearts were subjected to 30-min global ischemia followed by 2 h of reperfusion. The tocopheryl phosphate fed rats exhibited significant cardioprotection as evidenced by improved ventricular performance and reduced myocardial infarct size and cardiomyocyte apoptosis. Supplementation with α-tocopheryl phosphate converted MAP kinase-induced death signal into a survival signal by enhancing anti-apoptotic p42/44 ERK kinase and p38 MAPKβ and reducing pro-apoptotic proteins p38 MAPKα and JNK. In concert, the phosphorylation of pro-apoptotic c-Src was also reduced. Tocopheryl phosphate increased the DNA binding of the redox-sensitive transcription factor NFκB and potentiated the activation of anti-death protein Bcl-2 and survival signaling protein Akt. The results of this study demonstrated for the first time that tocopheryl phosphate could ameliorate myocardial ischemic reperfusion injury by converting ischemia/reperfusion-mediated death signal into a survival signal by modulating MAP kinase signaling.

New Thinking on Flame Retardants

No one wants their bed, couch, chair, computer, or TV to catch on fire. “If an ordinary upholstered chair in your home gets ignited, it can essentially take your whole house down,” says Richard Gann, a senior research scientist at the U.S. National Institute of Standards and Technology’s (NIST) Building and Fire Research Laboratory. The most flammable part of a mattress or couch is its plastic polyurethane foam cushioning, he explains. Once a fire gets through a chair or mattress’s fabric covering and into this cushioning, it can start a catastrophic reaction that quickly leads to “flashover,” in which nearly everything combustible inside a room ignites simultaneously. Until very recently, brominated flame retardants, especially polybrominated diphenyl ethers (PBDEs), were one of the main materials used to reduce the speed with which the plastic components of consumer goods including beds, couches, chairs, and electronics could be consumed by fire. However, growing evidence shows that PBDE compounds are escaping from the products they protect and making their way into the products’ users. Moreover, the chemicals may disrupt human thyroid hormone functioning and cause other health effects, prompting many nations to ban or suspend their use in new consumer goods. [For more information on the health effects of PBDEs, see “Unwelcome Guest: PBDEs in Indoor Dust, p. A202 this issue.] Although bromine- and chlorine-containing flame retardants are still used in some products, the need for new alternatives is being driven by a confluence of policy, standards, and pressure from environmental groups. Europe banned the use of two formulations, PBDE pentaBDE and octaBDE, in 2004, the same year they were withdrawn from the North American market. A third compound, decaBDE, was banned 1 April 2008 by the European Court of Justice. Stateside, Maine has banned the use of decaBDE, the only PBDE still on the market in North America, in mattresses and residential upholstered furniture produced and sold in that state, and will extend the ban to electronics in 2010. Washington prohibits the use of decaBDE in mattresses and sets a process for a future ban in furniture and electronics if the state can identify a safer and feasible alternative that meets fire safety standards. Asian countries and other U.S. states have similar legislation in the works. “Instead of adding new fire retardant chemicals that ultimately may be shown to cause health problems, we should be asking whether we need to use these chemicals or if there are other ways to achieve equivalent fire safety,” contends Arlene Blum, a biophysical chemist and visiting scholar at the University of California, Berkeley. “So many of the chemicals we have banned in the past were flame retardants—think about asbestos, polychlorinated biphenyls, polybrominated biphenyls, tris(2,3-dibromopropyl) phosphate, PBDEs—[and] they all ended up in the environment and in people,” she points out. “We need to think carefully about adding these sorts of chemicals to consumer products before there is adequate health information.”

Interaction of slow electrons with methyl phosphate esters

We report computed cross sections for low-energy elastic collisions of electrons with the methyl esters of phosphoric acid, monomethyl, dimethyl, and trimethyl phosphate, and with phosphoric acid itself. For phosporic acid and monomethyl phosphate, polarization effects are included in the calculation, while the two larger molecules are treated in the static-exchange approximation, that is, with polarization neglected. The integral elastic cross sections exhibit broad shape resonances above 5eV that give rise to strong variations in the differential cross section with energy. However, no shape resonances are evident below 5eV. We compare our results to previous calculations and measurements and discuss their relevance to electron-induced damage to the DNA backbone.

New promoters for the molybdenum hexacarbonyl- mediated Pauson–Khand reaction

A systematic study of new additives for the stoichiometric molybdenum hexacarbonyl- mediated Pauson-Khand reaction resulted in the discovery of several active compounds such as tetra- substituted thioureas, ester and amide derivatives of phosphoric acid, quaternary ammonium bromides and phosphine oxides. Tributylphosphine oxide (TBPO) was the most efficient additive providing PK products in moderate to good yields. Some experimental evidences were found which support a non-oxidative Mo(CO)6 activation by TBPO.

Oxygenate Conversion over Solid Phosphoric Acid

Conversion of olefins by solid phosphoric acid (SPA) catalysis is a key refining technology for the upgrading of high-temperature Fischer−Tropsch (HTFT) products. Oxygenates present in HTFT material suppress olefin conversion over SPA. A class specific study of SPA catalyzed conversion of alcohols, aldehydes, carboxylic acids, esters, ketones, acetals, and ethers is reported. In addition to well-known acid catalyzed organic reactions, high temperature acid-catalyzed reactions were also observed, such as the conversion of ketones to carboxylic acids and olefins. The following were specifically noted: (a) All of the oxygenates suppressed 1-hexene conversion, and the effect appeared to be related to water production; (b) aldehyde conversion to aromatics, including ethanal to benzene, was observed; (c) tributyl phosphoric acid ester was formed from 1-butanol, but 2-propanol was not converted into tri-isopropyl phosphoric acid ester.