Beiträge zur Analytik von Estersulfonaten

Contributions to the Analysis of Sulfonated Esters Several methods for the characterization and determination of α-Sulfo fatty acid methyl esters are described. The sulfonated ester is detected by thin layer chromatography on silica gel plates with tetrahydrofuran + acetone (1+9 v/v) as solvent and with pinacryptol yellow/UV-light for the visualization. Pyrolysis-gas liquid chromatogrphy with heating a sample/P₂O₅-mixture at 400°C yields the chain length distribution of the fatty acids initially used. The amount of an α-sulfo fatty acid ester is determined by extraction with i-propanol and by two-phase titration (Epton). the saponification product of the sulfonated ester is in the i-propanol insoluble part. For a quantitative determination of the α-sulfo fatty acid methyl ester by thin layer chromatography the sample solution is directly applied to the thin layer plate. A range of defined volumes, with increasing amounts of the sample are applied to the plate by means of an applicator. The chromatograms are visually compared. Ion chromatogrphy with the mobile phase, NH₃/Acetonitrile separates the α-sulfo fatty acid esters by chain-length. Determination is achieved by standards with defined chain-length.     

Synthesis and properties of a phosphate ester as curing agent in an epoxy resin system

Phosphate ester compounds display good flame retardancy effect in epoxy resin systems. In this paper, several novel phosphate esters, used as curing agents for epoxy resins, were synthesized based on P₂O₅, phosphoric acid, and different types of alcohol. The structures of phosphate esters were characterized by ³¹P nuclear magnetic resonance (³¹P NMR). Then, a series of flame retardant epoxy composites were prepared by curing the epoxy resins (E-44) with the phosphate esters. The flame retardancy and thermal degradation behaviors of flame retardant epoxy composites were investigated by cone calorimeter test (CCT) and thermogravimetric analysis (TGA), respectively. The results of CCT indicated that phosphate esters can significantly decrease heat release rate, total heat release (THR), and smoke production rate. The sample cured by butyl phosphate ester from phosphorus pentoxide, phosphoric acid and butanol showed the best flame retardant performance among all samples. The TGA results showed that phosphate esters could enhance char residues of flame retardant epoxy composites when compared with those of a composite using T31 as a curing agent at high temperature. It may be concluded that good flame retardant properties of flame retardant epoxy composites are related to the formation of a protective phosphorus-rich char layer. These phosphate esters have a good future on flame retardant epoxy composites.     

Reactions of phosphoric acid in the autoxidation of fats

At the elevated temperatures used in accelerated stability tests phosphoric acid was shown to react with fatty peroxides in such a manner as to prevent their estimation by the usual iodometric methods. A dark, phosphorus-containing precipitate formed, which was apparently polymeric in nature. Phosphoric acid also reacted with oxidized fat to form an undisassociated fat-soluble complex but did not react with fresh unsaturated fatty esters. In addition to the well known sparing action of phosphoric acid ona-tocopherol, it was shown thata-tocopherol and quinone also exerted a marked sparing action on the phosphoric acid.     

Successive processes for purification and extraction of phosphoric acid produced by wet process

Different technologies were tested for purification of phosphoric acid produced by the wet process. Iliminite clay was found suitable for removal of humic acids and suspended materials from crude phosphoric acid. Minimizing of ferric ions from phosphoric acid was carried out using silica, while removal of fluoride was proceeded by addition of carbonate salt. Isoamyl alcohol was used for extraction of P₂O₅ giving value of 78.5%. Using McCabe–Thiele diagram, the number of stages for complete extraction of P₂O₅ was predicted as two stages. Warm distilled water had a good efficiency for stripping of P₂O₅. Flow chart for sequential treatment process and extraction was constructed.     

EXTRACTION OF PHOSPHORIC ACID FROM NITRATE SOLUTIONS WITH ISOAMYL ALCOHOL

The extraction of phosphoric acid with isoamyl alcohol from aqueous solutions relevant to and produced by leaching of phosphatic iron ore by nitric acid has been studied. The results indicate that the extraction of phosphoric acid is not temperature dependent in the range 25–40°C, and that it increases with increasing the concentration of HNO₃ or H₂SO₄. The salting-out effect of the different nitrate salts on the extraction of phosphoric acid is found to be in the order of Mg²⁺> Ca²⁺ > Na+> NH+₄ K+. The presence of Fe³⁺ and Al³⁺ may reduce the extraction of phosphoric acid. Phosphoric acid can be extracted selectively against the different nitrate salts but nitric acid is coextracted. The excess coextraction of nitric acid from the aqueous phase will result in the precipitation of some phosphate complexes of Fe, Al, Ca, etc. Some tests of the continuous multistage extraction were also performed and a flowsheet for the recovery of the phosphoric acid is suggested.     

The estimation of mono and di alkyl phosphate in the presence of phosphoric acid and alcohol

Summary A method is presented for the determination of mono and di alkyl phosphates in the presence of the contaminants usually present when the sample is prepared by the reaction of P₂O₅ or H₃PO₄ on fatty alcohol. Total PO₄, free H₃PO₄, hydroxyl, ash, and water are determined by simple methods and the percentage of mono and di esters are calculated therefrom.     

Isomeric monoethylenic fatty acids in herring oil

Monoethylenic fatty acids from herring oil were concentrated by chromatography by chromatography on silver nitratesilicic acid columns. Examination of consecutive fractions by open tubular gas chromatography confirmed the preferential elution of longer chain length esters and of esters within one chain length with the double bond closer to the terminal methyl group. Isomeric monoethylenic fatty acids with double bonds in the positions closer to the carboxyl group than the approximate midpoint of the even-numbered fatty acid chains could not be adequately separated by gas chromatography and were determined by ozonolysis. The isomers observed are consistent with primary formation from saturated acids through the action of an enzyme specifically removing hydrogen atoms in positions Δ⁹ and Δ¹⁰ relative to the carboxyl group. Chain extension of particular monoethylenic isomers by two carbon atoms in the C₂₀ and longer chain lengths is apparently influenced by the position of the double bond. This work was carried out in partial fulfillment of MSc requirements at Dalhousie University.     

Evaluation of problematic indigenous phosphate deposits for phosphoric acid manufacture

To examine the possible utilization of indigenous phosphate reserves, bench scale studies were under-taken to assess their suitability for phosphoric acid manufacture.It was found out that in spite of few problems, the Silicious phosphate reserves of 2–3 million tons could be utilized for phosphoric acid manufacture, because low sulphuric acid consumption 2.52 ton acid/ton P₂O₅ and better P₂O₅ recovery yield (94.71) was achieved. The dolomitic phosphate reserves of 4–5 million tons (having 5–6% MgO) remained problematic, giving low P₂O₅ recovery yield (89.25) and higher sulphuric acid consumption 4.08 tons acid/ton P₂O₅.Product acid from the dolomitic reserves upon concentration became paste like at 36–38% P₂O₅ and therefore, these indigenous dolomitic phosphate reserves could not be utilized for the production of phosphoric acid.     

Fatty Acid Composition in Ergosteryl Esters and Triglycerides from the Fungus Ganoderma lucidum

Free and esterified ergosterols are detected almost solely in fungi and are often employed as a biomarker of living fungi. In this work, the fatty acid composition and δ¹³C values of major fatty acids in triglycerides and ergosteryl esters from the fungus Ganoderma lucidum were analyzed by gas chromatography–mass spectrometer and gas chromatography–isotopic ratio mass spectrometer, respectively. The results showed that the fatty acid profiles varied in triglycerides and ergosteryl esters. The percentage of saturated fatty acids in ergosteryl esters was remarkably higher than that in triglycerides, where C_18:1^Δ9c was the predominant fatty acid and constituted 61.26 % of the total fatty acids. In contrast, C_16:0 was the predominant fatty acid and constituted 71.88 % of the total fatty acids in ergosteryl esters. The study suggests that, after fungal death, free ergosterols in the cell membrane of the dead fungus were esterified with preferentially saturated fatty acids, mainly C_16:0, from triglycerides and then stored in lipid particles for a longer period while free ergosterol markedly decreased. The δ¹³C values of C_16:0, C_18:0, C_18:1 and C_18:2 in ergosteryl esters exhibit a pronounced depletion in ¹³C compared with that in triglycerides within the range of ?1.3 to ?0.9 ‰, supporting the above inference. It is again suggested that free ergosterol in the cell membrane should be used as an indicator of living fungi, and ergosteryl esters in the lipid particles should not be included in the measurement of living fungal biomass.     

The composition of beeswax alkyl esters

The alkyl esters of beeswax, after isolation from the unhydrolyzed wax by preparative layer chromatography (PLC), have been analyzed directly by high temperature GLC using 1.5% OV1 as liquid phase. In two commercial wax samples examined the ester homologues are predominantly even carbon numbered ranging from C₃₆ to C₅₄. The principal alkyl esters are C₄₀, C₄₂, C₄₄, C₄₆ and C₄₈. The GLC analysis of the ester hydrolysis products revealed that the variations in ester chain length are produced by variations in the esterified primary alcohol chain lengths. The esterified fatty acid is chiefly hexadecanoic acid. The esterified fatty acids differ in composition from the free fatty acids which are also present in the wax.     

The electrochemical hydrogenation of edible oils in a solid polymer electrolyte reactor. I. Reactor design and operation

A new electrochemical method has been devised and tested for the moderate temperature/atmospheric pressure hydrogenation of edible oils, fatty acids, and fatty acid methyl esters. The method employed a solid polymer electrolyte (SPE) reactor, similar to that used in H₂/O₂ fuel cells, with water as the source of hydrogen. The key component of the reactor was a membrane-electrode-assembly, composed of a RuO₂ powder anode and either a Pt-black or Pd-black powder cathode that were hot-pressed as thin films onto the opposing surfaces of a Nafion cation-exchange membrane. During reactor operation at a constant applied current, water was back-fed to the RuO₂ anode, where it was oxidized electrochemically to O₂ and H⁺. Protons migrated through the Nafion membrane under the influence of the applied electric field and contacted the Pt or Pd cathode, where they were reduced to atomic and molecular hydrogen. Oil was circulated past the back side of the cathode and unsaturated triglycerides reacted with the electrogenerated hydrogen species. The SPE reactor was operated successfully at a constant applied current density of 0.10 A/cm² and a temperature between 50 and 80°C with soybean, canola, and cottonseed oils and with mixtures of fatty acids and fatty acid methyl esters. Reaction products with iodine values in the range of 60–105 were characterized by a higher stearic acid content and a lower percentage of trans isomers than those produced in a traditional hydrogenation process.     

The potential of Hazara phosphates for phosphoric acid manufacture

The phosphate reserves in Pakistan are small. The largest ore body (Lagarban area) of Hazara Administrative Division located in the North East of the country has 3.25 (measured) and 6.71 (inferred) million tons phosphates rock of silicious and dolomitic nature with 25.8% average P₂O₅ contents besides high impurities of R₂O₃ (3.3%) and MgO (up to 6%).The deposits are not beneficiable by dry and wet screening due to significant phosphate losses which take place. Phosphate flotation recoveries are also low. Heavy intensity magnetic separation removes iron after the removal of dust from classified fraction. Acid leaching is efficient for removing MgO (up to 84%) with low P₂O₅ losses. However, removal of iron and MgO by these methods is not considered feasible on economic grounds.Laboratories and pilot plant processing trials showed that phosphoric acid of 23–25% P₂O₅ can be manufactured from Lagarban rock. As most of the impurities of the rock Fe₂O₃, Al₂O₃, MgO and part of SiO₂ are washed down during processing the resulting product acid is of poor quality with high viscosity.Triplephosphates prepared from this acid are hygroscopic and have low P₂O₅ availability (86%).To overcome the problem of these objectionable impurities in the product acid, removal of these impurities during the processing of phosphoric acid is required, i.e. aggolomeration with gypsum crystals-Pembrook pocess, Occidental process.     

The monounsaturated acyl- and alkyl-moieties of wax esters and their distribution in commercial orange roughy (Hoplostethus atlanticus) oil

Wax esters were isolated from commercial orange roughy (Hoplostethus atlanticus) oil by column chromatography and fractionated by argentation thin layer chromatography. Following transesterification, the resultant fatty acid methyl esters and fatty alcohols were analyzed by gas chromatography. both acyl- and alkyl-moieties were mainly of the monoene structure within the 16∶1–22∶1 range. After derivatization, the positions of the double bonds of even numbered fatty acid and fatty alcohol isomers were located by chromatography-mass spectrometry and compared. Results of these positional analyses indicate that the primary desaturation reactions takes place in the Δ9 position of pre-existing (C₁₄ to C₂₄) acyl chains. It is proposed that acyl components from 18∶1 are subjected to chain elongation to form a mixture of 24∶1 isomers as the final product. Apart from the 24∶1 acyl moiety of the wax esters, in which the double bond was almost exclusively in the Δ15 position, de novo biosynthetic reactions on acids and alcohols appear to yield related acyl- and alkyl-moieties of resynthesized wax esters.     

PURIFICATION OF WET PROCESS PHOSPHORIC ACID BY SOLVENT EXTRACTION WITH ISOAMYL ALCOHOL. PART II. STUDY OF THE IMPURITIES DISTRIBUTION.

ABSTRACT

In the present paper, information about the purifying of wet process phosphoric acid (WPA) by Isoamyl Alcohol (iA) is reported. Distribution coefficients of impurities such’ as Fe, Al, Mg, SO⁼ ₄and F, as well as the distribution of Phosphoric Acid (PA) and Isoamyl alcohol were obtained.

Furthermore the variation of the relative distribution coefficients and selectivities of the different impurities was studied as a function of the PA weight percent (wt%) in the organic phase. Removal of the impurities Fe, Al, Mg and SO⁼ ₄is favoured when decreasing PA wt% in the organic phase. Selectivity of F shows different behaviour, passing through a maximum when plotted against PA wt% in the organic phase     

Determination of physicochemical properties of some fatty acid methyl esters by gas liquid chromatography

Physicochemical data such as vapor pressures (p⁰), heats of vaporization (ΔH_v), activity coefficents at infinite dilution (γ^∞) and excess partial molar entropy (ΔS _e ⁰ ) are considered important for conducting unit processes and designing reactor equipment. Scanty information regarding such data is available in the literature for the higher fatty acid methyl esters. The objective of this research was to determine the physicochemical properties of higher fatty acid methyl esters (C₁₁–C₂₃) by a gas-liquid chromatographic technique with SE-30 and diethylene glycol adipate as stationary phases. Correlations between carbon numbers and various thermodynamic properties have indicated definite trends, which could be useful in predicting the properties of unknown fatty acid methyl esters. The data generated may be useful to chemical engineers in the construction of storage tanks, solvent extractors and distillation columns. IICT communication no. 2993.     

Formation of a thiamine disulfide complex with fatty acid: Mechanism of formation of the complex

The formation of complexes between thiamine disulfide (TDS) orO-acetyl thiamine disulfide (O-acetyl TDS) and fatty acid or fatty acid methyl ester in methanol has been studied by fluorescence quenching and¹³C NMR relaxation (T₁) measurements. The association constants (K-values) of TDS andO-acetyl TDS with fatty acids (from 11∶0 to 18∶0, and 18∶1, 18∶2, 18∶3 and 20∶4) and fatty acid methyl esters have been determined. These values do not depend on either the number of carbon atoms or the degree of unsaturation of the fatty acid. The K-values of TDS andO-acetyl TDS with fatty acid were 7.8 M⁻¹ and 5.1 M⁻¹, respectively. The K-values of TDS andO-acetyl TDS with fatty acid methyl ester were very small. These results show that the-OH moiety in TDS and the-COOH moiety in the fatty acid are necessary for formation of the complex     

Heart-Cut Two-Dimensional Countercurrent Chromatography for the Isolation of a Furan Fatty Acid Triacylglycerol from Latex Gloves and Identification of Further Lipid Compounds

Hevea brasiliensis latex from specific genotypes such as RRIM501 or PB235 is one of the richest natural sources of furan fatty acid 9-(3-methyl-5-pentylfuran-2-yl)-nonanoic acid (9M5), which is mainly present in the form of triacylglycerols. In this study, we successfully isolated a triacylglycerol esterified with three 9M5 molecules (tri-9M5) with a purity of 97% from the lipid extract of latex gloves by means of countercurrent chromatography (CCC). The gas chromatography with a mass spectrometry (GC/MS) spectrum of tri-9M5 not only featured the diagnostic fragment ion [M-RCOO]⁺ of triacylglycerols but also a fragment ion shifted by 16 Da to higher mass which corresponded with [M-RCO]⁺. [M-RCO]⁺ was only detected in triacylglycerols substituted with at least one furan fatty acid. Additionally, five γ-tocotrienyl fatty acid esters (γ-T₃-FA esters), namely, γ-T₃-16:0, γ-T₃-18:0, γ-T₃-18:1n-9, γ-T₃-18:2n-6 and γ-T₃-20:0, were detected in the sample. Contributions of γ-T₃-FA esters with 18:1n-9 and 18:2n-6 which co-eluted in GC/MS could be calculated after mathematical correction for contributions of the ¹³C₂ isotope peak of γ-T₃-18:2n-6 to γ-T₃-18:1n-9. This was necessary for quantitation of these two γ-T₃-FA esters. Improved separation of the γ-T₃-FA esters could be achieved by the novel heart-cut recycling CCC mode (four cycles). Sterols detected in disposable latex gloves were β-sitosterol, Δ⁵-avenasterol, and stigmasterol along with small quantities of 24-methylene-cycloartenol and Δ⁵-citrostadienol.     

Production of defluorinated dicalcium phosphate from phosphate rock concentrate

A new process to produce defluorinated dicalcium phosphate (DCP) using phosphate rock concentrate has been developed. This new process has as main characteristic the low concentration of P₂O₅ in the liquid phase. The process comprises three main steps: solubilization of the phosphate rock concentrate with sulfuric acid, defluorination of the phosphoric acid solution with potassium sulfate and neutralization of the phosphoric acid solution with calcium hydroxide. The P₂O₅ precipitated in the pH range between 2.00 and 5.00 consisted basically of anhydrous dicalcium phosphate. This revised version was published online in August 2006 with corrections to the Cover Date.     

Metathese ungesättigter Fettsäureester – ein einfacher Zugang zu langkettigen Dicarbonsäuren

Metathesis of Unsaturated Fatty Acid Esters – a Simple Approach to Long-Chained Dicarboxylic Acids Long-chained, symmetric unsaturated C₁₈-, C₂₀- und C₂₆-dicarboxylic acid esters are easily accessible from natural fatty acid esters by metathesis in a two-step procedure. In the first step unsaturated fatty acid esters are cleaved by metathesis with ethylene. Pure oleic acid ester or fatty acid methylesters, produced from high-oleic sunflower oil or from rapeseed oil by transesterification with methanol, are converted to 1-decene and 9-decenoic acid methylester. From erucic acid methylester 1-decene and 13-tetradecenoic acid methylester are achieved. Using our newly developed high efficient catalytic system B₂O₃-Re₂O₇/Al₂O₃-SiO₂ + SnBu₄ conversion rates of 86 – 96% are obtained and the terminally unsaturated fatty acid esters are isolated in yields of 61 – 83%. In the second step 9-decenoic and 13-tetradecenoic acid methylester as well as 10-undecenoic methylester, which is commercially obtained by pyrolysis of ricinoleic acid ester, are converted to 9-octadecenedioic-, 13-hexacosenedioic- and 10-eicosenedioic acid dimethylester, by which process ethylene is eliminated. The conversion rates are 89 – 99% and the dicarboxylic acid dimethylesters are isolated in yields of 77 – 84%.     

Occurrence of wax esters and 1-O-alkyl-2,3-diacylglycerols in goat epididymal sperm plasma membrane

Two unusual lipid classes were detected by thin-layer chromatography in the neutral lipids derived from goat cauda-epididymal sperm plasma membrane. The lipids were identified as wax esters and 1-O-alkyl-2,3-diacylglycerols based on chromatographic properties, identity of their hydrolysis products, and infrared/¹H nuclear magnetic resonance spectral evidence. The membrane containedca. 3 and 5 μg/mg protein of wax esters and alkyldiacylglycerols, respectively. The relative proportions of wax esters and alkyldiacylglycerols in the total neutral lipids were 1.5% and 2.4%, respectively. The lipids contained fatty acids with chain lengths of C₁₄ to C₂₂. The major fatty acids of the wax esters were 14∶0, 16∶0, 16∶1ω7, 18∶0 and 18∶1ω9. The fatty acids in alkyldiacylglycerol were 16∶0, 18∶0, 22∶5ω3 and 22∶6ω3. Alkyldiacylglycerol was particularly rich in docosahexaenoic acid 22∶6ω3) representing 30% of the total fatty acids. The alcohols of wax ester were all saturated with C₂₀–C₂₉ carbon chains. The deacylated products derived from alkyldiacylglycerols were identified as hexadecyl, octadecyl and octadec-9′-enyl glycerol ethers.