Metal Dialkyldithiophosphates Research Articles

Vapor-liquid equilibrium of metal dialkyldithiophosphates: An analysis with the statistical associating fluid theory

The vapor pressure osmometry (VPO) of metal dialkyldithiophospate (MDDPs) association in simple hydrocarbon solvents [1] has been analyzed using the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) [2]. From this analysis, we obtain a fluid-state free energy theory of MDDPs, including zinc dialkyldithiophosphates (ZnDDPs), an important class of multifunctional lubricant additives present in most automotive and commercial vehicle formulations marketed worldwide [3]. As expected, the PC-SAFT parameters of the MDDP compounds are found to vary smoothly with molecular size, metal atom type (Zn, Cd, Hg, Pb), and alkyl chain structure. Analysis of benzene/MDDP VPO isotherms with PC-SAFT suggests that selected MDDP compounds cross-associate with benzene.

Studying flotation properties of new collectors in scheelite-sulfide ore beneficiation

The article studies flotation properties of BTF-1552, IMA-206, and IMA-I413 alkali metal dialkyldithiophosphate samples. The article estimates beneficiation indices when using the reagent M-TF and its mixture with IMA-I413 and xanthogenate. On the basis of undertaken studies it was found that application of the mixture of IMA-I413 collectors with butyl xanthate at the ratio of 5 : 1 and the feed ratio of 20 + 5 g/t made it possible to increase the extraction into the copper concentrate: Cu by 0,79 %, Au by 4,1 % and Ag by 2,4, while the sulfide concentrate yield decreased by a factor of 2. The disadvantage of this reagent composition is the increase in As content in the copper concentrate by 0,67 %. Of all tested dialkyldithiophosphate samples, the best incremental indices of copper and noble metals recovery were obtained when using the BTF-1552collector. The extraction into the copper concentrate increased: Cu by 1,9 %, Au by 3,2 %, and Ag by 1,8 %, while the sulfide concentrate yield decreased by 1,4 times. The increase in As content in the copper concentrate was 0,34 %.

60]Fullerene metal complexes with large effective two-photon absorption cross-section

Fourteen novel complexes of fullerene C(60) with metal dialkyldithiophosphate, {[(RO)(2)PS(2)](2)M}·2C(60) (R = Me and Et; M = Mn, Fe, Co, Ni, Cu, Zn and Pd), can be obtained in high yield by the reaction of metal(II) dialkyldithiophosphate complexes with C(60) fullerene. Their structures are determined by (1)H, (13)C, and (31)P NMR spectroscopy, elemental analysis, FT-IR and UV-vis, and are supplied by single crystal X-ray data. The compound {[(EtO)(2)PS(2)](2)Pd}·2C(60) was also studied by the HRTEM image and SAED patterns. Studies of the optical properties of the complexes of fullerene C(60) with metal dialkyldithiophosphate show that these compounds all have very strong nonlinear optical absorption effects. The nonlinear absorption of fourteen complexes of fullerene C(60) with metal dialkyldithiophosphate (in o-dichlorobenzene and in the solid state) was measured by the open-aperture Z-scan technique at a wavelength of 532 nm. DFT calculations are also used to discuss the stability of these complexes and to confirm the structural assignments.

Thermolysis of Dialkyl Dithiophosphates in Porous Anodic Alumina Template: A Versatile Route to Produce Semiconductor Metal Sulfide Nanowires

Abstract A facile and versatile method characterized by thermolysis of metal dialkyl dithiophosphates in porous anodic alumina templates was proposed for producing semiconductor metal sulfide nanowires. Highly crystalline nanowires of binary metal sulfide ME (M = Cd, Pb, or Zn) have been prepared and characterized by X-ray diffraction and electron microscopy (SAED, SEM, and TEM).

Effect of the structure and metal atom of dialkyldithiophosphate derivatives on the wear behaviour in steel‐zirconia contacts

AbstractWear investigations concerning the different structures and metal atoms of metal dialkyldithiophosphates (MeDTPs) were conducted using a ball‐on‐disc apparatus. Steel ball bearings (3.175 mm in diameter) and counterface discs, made of hot pressed ZrO2 partially stabilised by Y2O3, were used. The synthesised MeDTPs were made up of primary linear aliphatic alcohols with hydrocarbon lengths varying from 8 to 16 carbon atoms, and contained the following metals: zinc(II), iron(III), gallium(III), antimony(III), and copper(II). Tests were performed at room temperature. The sliding speed was set to a constant 0.03 m/s, and a constant 30 N load was used. The additives investigated were used as solutions in n‐hexadecane.The study also focused on the influence of additive concentration on wear. It was found that the effectiveness in reducing wear depends both on the metal atom and on the length of the hydrocarbon chain in the additive's molecules. The lowest wear volumes were observed for additives with n‐octyl and n‐tetradecyl hydrocarbon chains. The worst antiwear performance was observed for n‐dodecyl derivatives. For almost all additives, more concentrated solutions resulted in less wear. Some friction coefficient results are also presented.

Photostabilization of poly-(2,6-dimethyl-1,4-phenylene oxide) films by metal dialkyl dithio-phosphate

The photostabilization of poly-(2,6-dimethyl-1,4-phenylene oxide) film in air, using Cd(II) O, O′-diisopropyl dithiophosphate as a stabilizer, in the temperature range 313–363 K with a light intensity flux of 8·7 × 10 −9 einstein s −1 cm −2, was investigated. The course of stabilization has been determined by means of light scattering, potassium ferrioxalate actinometry and gel formation. The extent of stabilization was also followed by IR and UV spectroscopy and by monitoring the formation of carbonyl and hydroxyl groups. These results have been used to support the proposed mechanism of photostabilization.

Kinetics of photo-oxidative degradation and stabilization of poly(2,6-dimethyl-1,4-phenylene oxide) by metal dialkyl dithio phosphate

The kinetics of photo-oxidative degradation and stabilization of poly(2,6-dimethyl-1,4-phenylene oxide) have been studied in the temperature range 313-363 K using monochromatic light of 365 nm with a constant intensity flux of 8.7 × 10−9 einstein s−1 cm−2 in the absence and presence of Ni(II) O,O′-diisopropyldithiophosphate. The course of degradation and stabilization was determined by means of light scattering and spectroscopic techniques. The extent of photodegradation was followed by carbonyl formation, gel content and activation energy. The incorporation of 1.2 wt% stabilizer in the matrix of the polymer films exercises the maximum protective influence on the photodegradation of the polymer.

ChemInform Abstract: Reactions of Metal Dialkyl Dithiophosphates. Part 4. The Crystal Structure of (Ag(S2P(OEt)2)2)2‐ 2, a Silver Anion Containing Monodentate and Tridentate Dialkyl Dithiophosphate Groups.

AbstractThe title compound (III) crystallizes in the space group P21/c with Z=2.

含硫黄金属錯体による酸化防止の作用機構

This is a review on the antioxidant action of transition metal dialkyldithiophosphates and dialkyldithiocarbamates in autoxidation of hydrocarbon. These complexes interrupt autoxidation by trapping chain-propagating peroxy radicals and by decomposition of hydroperoxides into non-radical products. Trapping peroxy radicals occurs at sulphur atom or at central metal atom of these complexes. Hydroperoxide decomposition proceeds in three stages, i. e. a fast homolytic decomposition followed by an induction period, and a fast heterolytic decomposition. In the first or the second stage, these complexes change into ionic catalysts which are responsible for the heterolytic decomposition of the third stage. The kinetics, the products and the mechanisms of inhibition by these complexes are summarized.

Metal complexes as antioxidants. 9. Application of the spin scavenging technique to the reaction of transition metal dialkyldithiophosphates and dialkyldithiocarbamates with tertiary alkyl hydroperoxides

The spin scavenging technique has been applied to the initial homolytic reaction between tertiary alkyl hydroperoxides and zinc and nickel complexes of dialkyldithiophosphoric acids and dialkyldithiocarbamic acids using low concentrations of Galvinoxyl and 2,2,6,6-tetramethyl-4-oxo-1-piperidinyloxyl as radical scavengers. This method has demonstrated that these transition metal complexes react with hydroperoxides at 303 K to generate free-radicals. Quantitative kinetic data have been obtained from zero-order scavenger decays and the efficiency with which the transition metal complexes generate free-radicals increases in the order Zn[R2NCS2]2 < Zn[(RO)2PS2]2 < Ni[(RO)2PS2]2 < Ni[R2NCS2]2. Deviations from zero-order scavenger decay have been observed, particularly at high complex concentrations, and have been attributed to reaction of the complex with transient radicals to give products which do not react rapidly with the scavenger.

Gas chromatography of some metal dialkyldithiophosphates with packed and capillary columns using flame photometric detection

Metal dialkyldithiophosphates are suitable for selective detection with a flame photometric detector operated in either the S 2 or HPO emission mode. Comparison of dta for packed and capillary columns shows that the sensitivity in the HPO mode is only slightly greater than, and in the S 2 mode comparable with, that in the flame ionization deterctor. In addition, it is notable that hte sensitivity to the chelates in the HPO mode is inferior to that for simple organophosphorus compounds by an order of magnitude. Background permeation of CS 2 leads to some improvement in detection limits for nickel dithiophosphate. Baseline resolution of palladium and platinum derivatives is readily achieved on wall-coated open-tubular columns.

Gas chromatography of volatile metal dialkyldithiophosphates

Examination of a wide range of metal dialkyldithiophosphates has shown that the diethyl and diisopropyl derivatives of nickel, palladium, platinum, chromium and rhodium can be successfully eluted by gas chromatography on inert diatomaceous-earth supports such as Gas-Chrom Q or Chromosorb 750 coated with silicone stationary phases OV-101, SE-30 or PS-300. The corresponding zinc chelates, although volatile, display considerable tailing on all columns tested, and it is proposed that this phenomenon may be due to the presence of dimeric species in the gas phase. Thermal analysis of other metal dialkyldithiophosphates show them to be non-volatile and unsuitable for gas chromatography.

NEW ASPECTS IN THE MECHANISM OF INHIBITORY ACTION OF SULPHUR CONTAINING METAL COMPLEX COMPOUNDS IN THE OXIDATION OF HYDROCARBONS

Abstract The first studies dealing with the antioxidizing action of sulphur containing organic compounds in the stabilization of petroleum products, polymers, rubber etc., suppose an interaction of these inhibitors with hydroperoxides and the decomposition of the latter to molecular inactive products. The absence of reaction of the peroxide radicals, leading the chain of the autoxidation, with the inhibitor is presumed. The initiating properties of the inhibitors-peroxide decomposers were unknown\1, 2,3\. As a result of our and other authors' investigations was shown, that the sulphur containing antioxidants react with the peroxide radicals and they are able to initiate the autoxidation processes, because in the oxidation of hydrocarbons in the simultaneous presence of hydroperoxides and sulphur containing compound, a prooxidizing effect is observed i.e. acceleration of the oxidation in a certain period of the process\4,5,6\. It was observed, that a period of rapid oxidation, followed by autoretardation of the oxygen absorption, appears in the oxidation of tetraline and cumene, respectively in the presence of tetraline and cumene hydroperoxides and metal dialkyldithiophosphates, dithiocarbamates and dithiolates. The oxidation of cumene and tetraline, initiated by AIBN at 60C in the presence of zinc dithiophosphate, zinc dithiocarbamate and nickel dithiolate, proceeds with the appearance of induction periods. In this way, the existence of interaction between RO.2 and sulphur containing metal complex compounds is verified The Stoichiometric coefficient of inhibition depends on the concentraton of the used inhibitor, which is a proof that in the induction period, the inhibitor is consumed not only by an interaction with the peroxide radicals, but by means of another reaction. This fact explains the existence of different values of the stoichiometric coefficients, measured by different groups of authors, using different initial concentrations of the studied inhibitors. At a definite correlation between AIBN and sulfur containing complexes in the oxidation of cumene, an effect of oscillation is observed i.e. the induction period is followed by a periodical change of the oxygen absorption rate \7,8\. The frequence of oscillation increases with time and the differences between the inflexion become greater. similar effect was observed in the initiated by AIBN oxidation of cumene in presence of Zn-bis(diisopropyl)dithiophosphate-(I), Zn-bis(diethyl)dithiocarbamate-(II),Ni-bis(diphenylethylene)-dithiolate-(III). The existence of oscillating effect obviously is due to the competition of two parallel processes-the absorption and the liberation of gas. With the help of mass spectral I analysis, it was shown that as a result of the reaction of (I), (II), (III) inhibitors and hydroperoxides, oxygen is liberated. The use of acceptors of synglet oxygen (9,10-diphenylantracene) shows that the liberated gas is synglet oxygen\9\.

Microcalorimetric study of adsorption of oil additives by metal

1. 1. Oil additives of various structures (trichloromethylphosphonic acid esters, metal dialkyldithiophosphates) differ as regards heat of absorption by metals, determined microcalorimetrically. 2. 2. With an increase in the heat of adsorption of oil additives on metal, anti-wear properties improve on testing in a friction testing machine under low contact loads.

Intensity of characteristic bands in spectra of metal dialkyldithiophosphates

Integral intensities have been measured for the C-O-(P), P=S, and P-S bands in the spectra of potassium, barium, zinc, nickel, and lead dialkyldithiophosphates containing hydrocarbon radicals of various structures.

Infrared study of the effect of additives on motor oil oxidation

1. The antioxidation mechanism of oil additives can be examined by testing the oil under the severe test procedure method on a PZV rig, and then examining the oil by infrared spectroscopy. 2. This analytical method includes taking the IR-spectra (over the wave number rangeν =400–2000 cm−1) of the oxidized doped oil relative to air, fresh undoped oil, and the original doped oil. The background exclusion method is used for treating the spectra quantitatively. 3. Metal dialkyldithiophosphates at levels of 1% do not lead to any change in the composition of the oxidation products of the oil; differences in their efficiency only show up in the amount of oxidation products formed. Additives of this type reduce the content of oxygen-containing products in the oil 2–4 times. 4. The effect of metal sulfonate and alkylphenolate additives shows up specifically in an intensified formation of carboxylic acid salts. Calcium sulfonate also leads to an increase (2–3 times) in the amount of alcohols, ethers, and carboxylic acids in the oil. Barium alkylphenolate promotes a slight change in the ratio of the oxidation products; on the whole, however, accumulation of oxygen-containing compounds in the oil is retarded. 5. A copolymer based on methacrylate and a nitrogen-containing compound leads to the formation of increased amounts (1.5 times) of oxygen-containing compounds.

Comparative study of the antioxidant and anticorrosion properties of metal dialkyl- and diaryldithiophosphates

1. Laboratory tests have been conducted of metal (Ba, Ca, Zn, Pb, Ni) dialkyl and diaryldithiophosphates and also of zinc dialkylmonothiophosphate and phosphate as antioxidants and corrosion inhibitors at various temperatures. It is shown that all the compounds tested, except for zinc di(2-ethylhexyl) phosphate, retard the oxidation of hydrocarbons and are corrosion inhibitors. With an increase in temperature the action of the majority of additives is weakened. 2. Zinc and barium dinonylphenyldithiophosphates exhibit the greatest antioxidant and anticorrosion properties at ail temperatures tested. 3. It has been established that the anticorrosion activity, and the antioxidant activity of additives of the metal dialkyldithiophosphate type is caused primarily by the presence of thioic sulfur.

The Load-Carrying Properties of Metal Dialkyl Dithiophosphates: The Effect of Chemical Structure

The extreme pressure (e.p.) and mixed lubrication or antiwear (a.w.) properties of a range of metal dialkyl dithiophosphates have been examined using the four ball machine. The results show that the nature of the metal atom is a major factor in determining these properties, and that the factors governing e.p. and a.w. activities are different. Thus the order of decreasing e.p. activity is Bi(III) > Ag(I), Pb(II) > Sb(III), Sn(II) ≥ Cd(II), Fe(III), Ni(II) > Zn(II), whilst the order of decreasing a.w. activity is Cd(II), Zn(II), Ni(II) ≥ Fe(III) > Ag(I) > Pb(II) > Sb(III), Sn(II) > Bi(III) for a series of 4-methylpentyl-2 and n-hexyl salts. The nature of the alkyl group has a lesser effect on either e.p. or a.w. properties. Possible explanations for these results are presented.

Load-Carrying Properties of Metal Dialkyl Dithiophosphates: Application of Electron Probe Microanalysis

The surface topography and the nature of the surface layer of wear scars obtained with Bi(III), Pb(II), Cd(II), Ni(ll), and Zn(II) di-(4-methylpentyl-2) dithiophosphates, using the four-ball machine, have been studied using an electron probe microanalysis (EPMA) technique. The results show that the nature of the dithiophosphate markedly affects the surface topography, element content, and distribution of the wear scar in both the extreme pressure and mixed lubrication or antiwear regions. The implication of these EPMA results on the load-carrying mechanism of metal dialkyl dithiophosphates is discussed.

Infrared absorption spectra of metal dialkyldithio-phosphates

Infrared absorption spectra of metal dialkyldithio-phosphates