Tributyl Phosphite Research Articles

Tribochemical Mechanisms of Trimethyl and Triethyl Phosphite on Oxidized Iron in Ultrahigh Vacuum

The surface chemistry of model lubricant additives, trimethyl phosphite (TMPi) and triethyl phosphite (TEPi), is studied on oxidized iron in ultrahigh vacuum (UHV) and the results compared with the gas-phase lubrication of TEPi on oxidized iron in a UHV tribometer. Oxide films are grown on a polycrystalline iron substrate and characterized by X-ray photoelectron spectroscopy (XPS) and assigned to the formation of an Fe3O4 film. Measurements of the friction coefficient and contact resistance of the oxide films show that the oxide film remains intact while rubbing in UHV at a normal load of 0.29 N. It is found that phosphite esters adsorb on the oxide by electron donation to the phosphorus atom, with a binding energy that increases in the order tributyl phosphite > TMPi > TEPi, and correlates well with the location of the vacant lowest-occupied molecular orbital (LUMO) energy. The phosphite esters decompose via sequential P‒O bond scission to form adsorbed alkoxy species, which then react on the surface either by hydrogen addition to form the corresponding alcohol, or by hydrogen abstraction to yield an aldehyde. XPS studies of the surface shows that essentially no carbon remains after the TMPi has reacted, while a small amount of carbon is present when TEPi has decomposed. On heating, the phosphite esters convert to phosphate species. Gas-phase lubrication experiments in the presence of 1 × 10−7 Torr of gas-phase TEPi reveal that the friction coefficient is significantly reduced, where the friction reduction is found to increase with increasing reaction temperature. The friction reduction correlates well with the proportion of phosphate product formed in the film and indicates that the formation of phosphate tribofilm is primarily responsible for reducing friction. However, friction is also reduced for a reaction at ~ 300 K, lower than the temperature at which the adsorbed phosphite ester reacts, suggesting that its rate of decomposition could be accelerated by interfacial shear.

A derivatization strategy for the detection and identification of volatile trialkylphosphites using liquid chromatography-online solid phase extraction and offline nuclear magnetic resonance spectroscopy

We demonstrate herein the application of selective derivatization method that converts volatile and labile trialkylphosphites (TAPs) into virtually non-volatile, thermally stable, and UV absorbing derivatives. After simple sample preparation, purification/enrichment of the derivatives was achieved by using high performance liquid chromatography (HPLC) coupled to on-line post column solid phase extraction (SPE) system. These derivatives were subjected to 31P{1H} NMR and 1D-selTOCSY experiments. Conclusive identification was achieved on the basis of their HPLC retention time and NMR spectral signatures (δH1,δpE1, nJH–H, and 3JP–H). This method was tested for the unambiguous identification of a mixture containing low concentrations (∼10μgmL−1) of trimethylphosphite (TMP), triethylphosphite (TEP), triisopropylphosphite (TIP), and tributylphosphite (TBP) along with a high concentration of irrelevant background chemicals. It offered a high dynamic range and good detection limit and recovery (>75%) without the need for special NMR probe heads or exotic NMR experiments.

Activated carbons with well-developed microporosity and high surface acidity prepared from lotus stalks by organophosphorus compounds activations

Eight organophosphorus compounds, trimethyl phosphate (TMP), tributyl phosphate (TBP), triphenyl phosphate (TPP), trimethyl phosphite (TMPI), tributyl phosphite (TBPI), triphenyl phosphite (TPPI), diethyl phosphite (DEPI) and diphenyl phosphoryl chloride (DPPC), were employed as activating agents to prepare activated carbons (AC-OPCs) from lotus stalks (LS). AC-OPCs contained mostly micropores with only a small contribution of mesopores and their pore sizes were mainly below 4nm. Physical and chemical analysis results indicated that activations with OPCs dramatically enhanced the porosity, yield and surface acidity of AC-OPCs.

The mechanism of iron phosphide formation during boundary friction in the presence of organic phosphates and phosphites

Thermochemical and mechanochemical reactions of tricresyl phosphate, tributyl phosphate, and tributyl phosphite with an iron surface are studied. A possible mechanism of iron phosphide formation under severe boundary friction conditions is proposed. The antiscoring behavior of phosphine in a vaseline oil solution is studied for the first time. It is found that (a) iron powders modified by tricresyl phosphate or tributyl phosphite do not yield iron phosphide at a temperature of 710°C in vacuum but are reduced to iron phosphide by birch coal; (b) at a temperature of 760°C in a flow reactor, tricresyl phosphate produces a much greater amount of solid phosphorous-containing residue than tributyl phosphite; (c) at a temperature of 760°C in a flow reactor, tributyl phosphite produces white phosphorus; (d) phosphine improves effectively the antiscoring properties of vaseline oil.

Triethyl and tributyl phosphite as flame-retarding additives in Li-ion batteries

This study examined the influence of triethyl and tributyl phosphite (TEP and TBP) additives on the electrochemical performance of lithium-ion cells. The cell performance of the TEP- and TBP-containing electrolytes was evaluated by cyclic voltammetry, thermogravimetric analysis, electrochemical impedance spectroscopy, Fourier transform infrared spectroscopy and scanning electron microscopy. The flammability of the electrolytes was also investigated by measuring the self-extinguishing time of the electrolytes. The results showed that the TEP and TBP additives suppressed the flammability of the electrolyte, with a significant improvement in cell performance observed for the TEP additive. In addition, TEP and TBP additives improved the thermal stability of the battery and its electrochemical cell performance. Overall, 5 wt% TEP and TBP can be used as a flame-retarding additive to improve the cell performance of Li-ion batteries due to the decrease in cell impedance and SEI formation.

A study of carbonaceous products formed in the thermolysis of tricresyl phosphate, tributyl phosphate, and tributyl phosphite

The composition and morphology of carbonaceous products formed upon the thermal decomposition of tricresyl phosphate, tributyl phosphate, and tributyl phosphite at a temperature of 760°C in a fused-silica flow reactor have been studied for the first time. It has been shown that they contain P-O-C bonds and are graphite-like clusters with a size of ≤1 nm self-assembled into spherical or fibrous structures.

Surface reactivity of tributyl thiophosphate: effects of temperature and mechanical stress

The surface reactivity of tributyl thiophosphate on iron surfaces has been studied in situ by attenuated total reflection Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy and temperature-programmed reaction and desorption spectroscopies. The results show that at temperatures lower than 373 K the molecule forms a physisorbed layer on the iron substrate. At 373 K a reaction takes place with the formation of an organic layer, together with iron polyphosphate and sulfate. At higher temperatures temperature-programmed desorption results suggest that the mechanism involves P–O bond scission to yield butoxy groups. This could be preceded by P=S bond scission to give tributyl phosphite, which then, in turn, undergoes P–O bond scission to produce butoxy groups. The results obtained following tribological testing are in agreement with those of thermal tests: evidence of polyphosphate and sulfate formation is found.

Reaction of tributyl phosphite with oxidized iron: surface and tribological chemistry.

The surface chemistry of a model lubricant additive, tributyl phosphite (TBPi), is investigated on Fe3O4 in ultrahigh vacuum. A portion of the TBPi desorbs molecularly following adsorption at approximately 200 K, the remainder decomposing either by C-O bond scission to form 1-butyl species or by P-O bond cleavage to form butoxy species. Adsorbed butyl species either undergo beta-hydride elimination to desorb 1-butene or decompose to deposit carbon and hydrogen on the surface. The resulting adsorbed hydrogen reacts with the oxide to desorb water or with the butoxy species to form 1-butanol. Butoxy species are stable up to approximately 600 K at which temperature they also undergo beta-hydride elimination to form butanal and the released hydrogen reacts with other butoxy species to form 1-butanol. Only a small amount of carbon is deposited onto the surface following adsorption at approximately 200 K, which then desorbs as CO above approximately 750 K. Adsorbing TBPi at 300 K results in the deposition of more carbon and an Auger depth profile reveals that the carbon is located predominantly on the surface, while the phosphorus is rather uniformly distributed throughout the oxide film. This result is in accord with previous near-edge X-ray absorption fine structure measurements, which show the formation of phosphates and polyphosphate glasses. The resulting tribological film appears to be composed of a relatively hard polyphosphate glass formed by rapid diffusion of POx species into the oxide, covered by a low shear strength graphitic layer.

Praseodymium nitrate and neodymium nitrate complexation with organophosphorus reagents in supercritical carbon dioxide solvent

Complex formation reactions of praseodymium nitrate hexahydrate, and neodymium nitrate hexahydrate salts with tri- n-butyl phosphate (TBP) and several other neutral organophosphorus reagents were investigated in supercritical carbon dioxide. The concentration of the metal complexes in the supercritical fluid (SCF) phase was determined using UV-Vis and luminescence spectroscopies. The stoichiometry of the complexes was determined using the mole-ratio method. Extraction equilibrium constants were calculated from the spectral data using least-squares regression and hard-equilibria models. UV-Vis absorbance data indicate that praseodymium nitrate and neodymium nitrate both form 1:4 lanthanide–tributyl phosphate complexes in supercritical carbon dioxide at 308 K. The conditional extraction coefficients for those two systems were calculated to be log K ex=7.45±0.06 for the praseodymium system and log K ex=7.52±0.03 for the neodymium system. For comparison, neodymium nitrate complexation reactions with tri- n-butyl phosphate and tributyl phosphite (TBPO 3) were studied in hexane under ambient conditions. UV-Vis data indicate that a 1:4 neodymium–tributyl phosphate complex is formed in hexane with a conditional extraction coefficient of log K ex=3.4±0.2. Tributyl phosphite forms a 1:8 complex with neodymium in hexane with a conditional extraction coefficient of log K ex=11.0±0.1. Neodymium nitrate was titrated with other organophosphorus reagents, tributyl phosphite and tributyl phosphine oxide (TBPO), in supercritical carbon dioxide to investigate differences between neutral oxygen donor ligands and neutral phosphorus donor ligands. UV-Vis and luminescence data indicate that neodymium nitrate forms a 1:8 complex with tributyl phosphite and a 1:5 complex with tributyl phosphine oxide, compared to a 1:4 complex with tri- n-butyl phosphate. The conditional extraction coefficient for the 1:8 neodymium–tributyl phosphite system was calculated as log K ex=21.4±0.2 from UV-Vis data, and log K ex=19.8±0.2 from luminescence data. The conditional extraction coefficient for the 1:5 neodymium–tributyl phosphine oxide complex was calculated as log K ex=7.83±0.05.

Sol-gel synthesis of ternary phosphate-ZrO2-SiO2 catalysts for alcohol dehydration

Phosphate–ZrO2–Si2O catalysts were synthesized by sol-gel method using tributyl phosphite, zirconium propoxide, and tetraethyl orthosilicate as precursors. They were characterized by N2 adsorption, 31P CP MAS NMR, and DRIFTS. At lower P content, monomeric phosphates were formed on the surface of the catalysts, which were mainly responsible for the isopropanol dehydration activity. At higher P content, polyphosphates were formed, and thus, the dehydration activity decreased. An optimum P content for dehydration activity was found to be at 10 mol%.Key words: sol-gel synthesis, ternary oxides, phosphate, acid catalyst, alcohol dehydration, 31P CP MAS NMR, N2 adsorption, DRIFTS.

Electro-oxidative and electro-reductive dissociation of adducts between (η5-cyclopentadienyl) (1,2-disubstituted 1,2-ethylenedithiolato) cobalt (III) complexes and tributylphosphane or tributyl phosphite

Abstract The voltammetric characteristics of the title adducts [Co(Cp) (S 2 C 2 X 2 L] (X CN, CF 3 , COOCH 3 , 4-pyridyl, phenyl; L = tributylphosphane or tributyl phosphite) in acetonitrile solutions are reported. Both the phosphane and the phosphite adducts were oxidized and reduced through one-electron transfer processes followed by homogeneous chemical reactions for all X except phenyl; the oxidized adduct dissociated into the free complexes [Co III (Cp) (S 2 C 2 X 2 ] and the cation radical L +· , and the reduced adduct rapidly dissociated into the reduced form of the free complexes [Co II (Cp) (S 2 C 2 X 2 )] − and L. When X = phenyl, the oxidation was similar but the reduction was preceded by the dissociation of L. The oxidation and reduction half-wave potentials of the adducts were more negative than those of the corresponding free complexes, and they were linearly dependent on the adduct formation constant.

Static secondary ionization mass spectrometry analysis of tributyl phosphate on mineral surfaces: Effect of Fe(II)

The static secondary ionization mass spectrometry (SIMS) spectrum of tri-n-butyl phosphate (TBP) on a variety of basalt and quartz samples is affected by the chemical composition of the mineral surface. When TBP is adsorbed on Fe(II)-bearing surfaces, the compound undergoes concomitant H(-) abstraction and reduction, followed by the elimination of two C4H8 molecules to form an ion at m/z 137(+). When TBP is adsorbed to quartz or other nonreducing surfaces, it merely undergoes protonation and elimination of three C4H8 molecules to form H4PO 4 (+) . When TBP is adsorbed to Fe(III)-bearing surfaces, it undergoes H(-) abstraction and elimination of two C4H8 molecules, to form an ion at m/z 153(+). These conclusions are supported by model studies that employed FeO, Fe203, TBP, and tributyl phosphite. The results show that the SIMS spectrum is very sensitive to the mode of TBP adsorption on the mineral surface.

Reductive rearrangements of silylated penicillin G 1-oxide

The reaction of penicillin G 1-oxide with BSU followed by treatment with tributyl phosphite gives, after hydrolysis, crystalline thiazoline azetidinone 2. Addition of triethylamine after reduction resulted in the formation of the isomeric thiazoline azetidinone 3.

Synthese von DD‐Heptosephosphaten als Substrate oder potentielle Inhibitoren für die Heptose‐Synthetase

Synthesis of DD‐Heptose Phosphates as Substrates or Potential Inhibitors for the Heptose SynthetaseA synthesis of D‐glycero‐D‐manno‐heptose (DD‐Hep) via an inversion of L‐glycero‐D‐manno‐heptose (LD‐Hep) is described. Starting from DD‐Hep the α‐1‐phosphate 3 and the α‐1‐methylphosphonate 30 were synthesized. Furthermore, the α‐1‐dialkyldithiophosphate esters from DD‐Hep were prepared. The 2,3,4,6, 7‐penta‐O‐benzyl‐D‐glycero‐α‐D‐ manno‐heptosyl trichloroacetimidate (22) turned out to be a very successful glycosyl donor in the reaction with the phosphate esters. The amidophosphates 41 and 42 of DD‐Hep have been synthesized according to the Staudinger reaction using glycosyl azides of DD‐Hep and tribenzyl or tributyl phosphite. The modified phosphates represent potential inhibitors for the heptose synthetase, an enzyme of the biosynthesis of the inner core region of lipopolysaccharides. Reaction of the phosphate 3 with AMP morpholidate afforded ADP‐DD‐Hep 4 which represents the product of the heptose synthetase enzyme reaction. magnified image

Synthesis, electrochemistry, and kinetic investigations of low-spin ferrous bis(difluoroboryl)bis(dioximate) complexes

The synthesis of new trans-Fe(dioxBF 2 ) 2 (CH 3 CN) 2 complexes (diox=dimethylglyoximate, naphthoquinone dioximate, benzoquinone dioximate) complexes and their conversion to a variety of Fe(dioxBF 2 ) 2 TL complexes (T or L=acetonitrile, 1-methylimidazole, pyridine, tributyl phosphite, tributylphosphine, tert-butyl isocyanide, tosylmethyl ioscyanide, carbon monoxide) is described. Kinetic and equilibrium data for the CH 3 CN derivatives obtained by spectrophotometric and flash-photolysis methods in acetonitrile solution and in toluene are compared with data for other FeN 4 systems

Separation of palladium from platinum using synergistic extraction

A synergistic effect was observed for the extraction of Pd when a solution containing trace amounts of PtIV and PdII was extracted with chloroform containing 8-hydroxyquinoline (HQ) and tributylphosphite (TBPI). Proton nuclear magnetic resonance (NMR) spectroscopy and thermogravimetry were used to confirm the composition of the synergistic species extracted. The NMR spectrum indicated that HQ and TBPI were present in a ratio of 1 : 1. From thermogravimetric analysis the extracted species was postulated to be Pd.Q.TBPl.Cl. From these results an extraction mechanism was proposed for the synergistic phenomena observed in these systems. When each extractant was used separately the ratio of the separation of Pd and Pt was found to be approximately 20 : 1. In contrast, the separation ratio increased to ca. 2000 : 1 when a combination of HQ and TBPI was used for the extraction. The proposed method was applied to a synthetic sample solution, the composition of which was similar to that of anode slime obtained from an electrolytic copper refinery. The results indicated that trace amounts of Pd (ca. 5 × 10–4M) could be separated effectively from equal amounts of Pt.

ChemInform Abstract: Ruthenium Catalyzed N‐Methylation of Aminoarenes Using Methanol.

AbstractThe aniline derivatives (I) and (IV) are methylated with methanol (II) in the presence of catalytic amounts of ruthenium trichloride hydrate/ tributyl phosphite or dichlororuthenium tristriphenylphosphine complex to yield the corresponding N‐methylation products (III) and (V).

Ziegler‐type propene polymerization catalyst systems involving tributyl phosphite as modifier

AbstractTributyl phosphite (1) was studied as modifier of heterogeneous TiCl3/(C2H5)2AlCl propene polymerization catalyst systems. When used as the sole modifier, 1 was found to produce catalyst systems with substantially improved stereospecificity and only slightly depressed activity relative to the unmodified catalyst system. Binary modifier packages consisting of 1 and bis‐(tributyltin) sulfide lead, apparently through synergism, to catalyst activities surpassing that of the unmodified catalyst system and to excellent stereospecificity (hexane extractables; 1,6–2,1%). Catalyst systems modified with 1 and triphenylantimony sulfide were also demonstrated to exhibit activities approaching or even exceeding that of the unmodified catalyst system with 2,1–2,3% hexane extractables, while systems involving 1 and triethyl thiophosphate as modifiers are more stereospecific (hexane extractables: 1,80%), but somewhat less active than the preceding system. Possible interactions and reactions of 1 with the components of the catalyst system are discussed.

ChemInform Abstract: REACTION OF OXOCHLOROALKENES WITH PHOSPHOROUS ACID ESTERS

AbstractDie Oxochloralkene (I), deren Herstellung beschrieben wird, reagieren mit Tributylphosphjt (VI) zu den Oxaphospholenen (VII).

Use of organophosphorus(V) sulfides for the modification of propene polymerization catalysts

AbstractStudies of various organophosphorus(V) sulfides, including esters of thiophosphoric acid and triorganophosphine sulfides, were evaluated as propene polymerization catalyst modifiers. Among these, triethyl thiophosphate (1a) leads to the best activity‐stereospecificity combinations. Higher alkyl or aryl esters of thiophosphoric acid lead to higher catalyst activities but significantly poorer stereospecificities, relative to 1a, while the latter modifier is advantageous over triaryl‐ or tris(diakylamino)phosphorus sulfides, as far as both activity and stereospecificity are concerned. Organophosphorus(V) sulfides appear to be better modifiers in general than the corresponding oxides. No straightforward correlations of the modifying effects of the preceding compounds to the inductive and steric effects of the substituents on phosphorus were possible, as some of these compounds (namely the thiophosphoryl or phosphoryl alkyl esters) may undergo dealkylation reactions with the components of the catalyst system, yielding alkyl chloride, traces of HCl and alkene, and polymeric metal (Ti3+ or Al3+) complexes with anionic R2POS− ligands. A number of binary modifier (1a plus an additional modifier) packages with attractive performance characteristics were developed. Evaluations of these systems in 2 h bulk propylene polymerizations showed that use of triphenylantimony oxide (8) as additional modifier leads to the best overall catalyst performance (yield: 2636 g/g AA TiCl3; hexane extractables: 0,80%). With the 1a‐collidine (9) modifier package, comparable stereospecificity but substantially lower catalyst activity were realized, while use of bis(tributylin) sulfide (6), tributyl phosphite (7) or 2,5‐dimethyltetrahydrofuran (10) as additional modifiers led to good yields (2650–3000 g/g AA TiCl3) but more than double (1,70–2,00%) the hexane extractables, relative to the 1a–8 modifier system.