Studies of waxes. VI. The n-acids of carnauba wax

Summary The proportion of normal acids among the acids of carnauba wax has been found, by a chromatographic separation method, to be 38%. The normal acid mixture has been separated into its components by amplified distillation of the methyl esters, which revealed the presence of the acids of even carbon number from C₁₈ to C₃₀. The acids were identified by their melting points, long crystal spacings, and crystal habit. An estimate of their relative amounts is as follows: C₁₈, 3%; C₂₀, 11.5%; C₂₂, 9%; C₂₄, 30%; C₂₆, 12%; C₂₈, 16.5%; C₃₀, 7%. Part V of this series: The Aliphatic Alcohols of Wool Wax, by K. E. Murray and R. Schoenfeld, J. Am. Oil Chem. Soc.,29; 416–420 (1952).     

Cuticular lipids of the booklouse,Liposcelis bostrychophila: hydrocarbons,aldehydes, fatty acids,and fatty acid amides

The booklouse, Liposcelis bostrychophila, is an increasingly common pest of stored food products worldwide. We report here the cuticular lipid composition of this pest (the first report of the hydrocarbons of any member of the Order Psocoptera and the first report of fatty acid amides as cuticular components for any insect). No unsaturated hydrocarbons were present. A homologous series of n-alkanes (C₂₁–C₃₄), monomethyl alkanes (3-, 4-, 5-, 7-, 9-, 11-, 12-, 13- and 15-methyl-) with a carbon chain range of C₂₈–C₄₂, and dimethyl alkanes (3, 7-; 9, 13-; 11, 15-; 13, 17-; 9, 21-; 11, 19-; and 13, 21-); with a carbon number range of C₃₁–C₄₃ were identified. The relative abundances of these hydrocarbons were low, comprising approximately 0.0125% of total biomass. The amides were a homologous series (C₁₆–C₂₂ in chain length), with the major amide being stearoyl amide. In addition to the amides, free fatty acids (C_16:1, C_16:0, C_18:2, C_18:1, and C_18:0 in chain length) and three straight chain aldehydes (C₁₅, C₁₆, and C_17:1 in chain length) also occurred as cuticular components. These findings are discussed in terms of the chemical and physiological ecology of this species.     

GC-MS detected difunctional carboxylic acids released by driedCladophora at the pH of lake ontario and the st. lawrence river

A study to identify the acidic components ofCladophora glomeata active againstAedes triseriatus larvae was extended to a mixture obtained by extracting the dried powdered alga in aqueous suspension at pH 8.5. The presence of 1,9-nonanedioic, 1,10-decanedioic, 1,11-undecanedioic and 4-ketononanoic acids was determined by GC-EIMS and GC-CIMS and confirmed by analytical coinjection GC. The presence of 5-pentyldihydro-2(3H)-furanone, a minor component, was also indicated. The group of major acidic constituents is different from those obtained by extracting driedCladophora with methanol. In contrast to the C₁₀–C₁₄ monocarboxylic acids, which hadLD ₅₀ values<20 ppm againstA. triseriatus, none of the dicarboxylic acids of the series G₄–C₁₄, C₁₆, and C₂₂ were active; nor were 4-ketononanoic acid and 5-pentyldihydro-2(3H)-furanone active.     

Explosive Hazard of Vapor–Gas Mixtures of Fluoride‐Containing Saturated Hydrocarbons with Fluoride and Chlorine Trifluoride

The limits of explosion of the CF₃CFH₂–F₂–N₂, C₃F₈–F₂–N₂, C₄F₈–F₂–N₂, C₄F₈–ClF₃–N₂, C₄F₁₀–ClF₃–N₂, and F₂ClCF₂Cl–F₂–N₂ mixtures are determined. For some compositions of the first two mixtures, the maximum pressure of explosion and the maximum pressuregrowth rate are measured. The transition from deflagration to detonation is observed in undiluted mixtures close to stoichiometric compositions. The burning rates of the mixtures examined are comparable with the burning rates of oxygen–hydrogen mixtures.     

Comparative analytical studies of fatty acids of the algaChlorella pyrenoidosa

Gas-liquid chromatography, several versions of paper chromatography, and alkaline isomerization have been applied to one preparation ofChlorella fatty acid methyl esters. GLC outranks other methods in rapidity, reproducibility, and resolving power. The presence of nonvolatile components in the sample can lead to erroneous results. Among PC methods which might arise from autoxidation and polymerization are detected. Esters or acids with 14 or fewer C atoms should be analyzed as nonvolatile derivatives. AI, as used here, introduces a systematic error in the determination of linoleic and linolenic acids. The quantitative results of the methods are in agreement for the major components, which all belong to the C₁₀ and C₁₈ series. A number of minor components have been revealed by GLC and/or PC. They are tentatively identified as <C₁₂, C₁₂, four C₁₄, C₁₅, two C₁₇, C₁₉, three C₂₀, two C₂₂, and C₂₄ acids. Several of these compounds have been found independently by different methods in hydrogenated form or as radioactive esters. This enhances the certainty of their identification. Eurichment by fractional distillation was essential for their detection. Possible losses in their distillation and other considerations make uncertain the assay of most of the minor components by GLC or PC. Work supported in part by grant RG-4226 from the Division of General Medical Sciences of the U. S. Public Health Service and in part by the Hormel Foundation.     

The fatty acids of menhaden oil

Summary Analysis of the fractions obtained as a result of distillation of the methyl esters of the hydrogenated acids of menhaden oil show the amounts indicated (wt. %): C₁₄, 6.9; C₁₆, 30.4; C₁₈, 26.8; C₂₀, 17.5; C₂₂, 10.8; C₂₄, 4.0; C₂₆, 1.2; above C₂₆, 2.4. In addition, about 0.1% of C₁₂ acids was demonstrated previously. Presented in partial fulfillment of the requirements for the degree of doctor of philosophy in the Graduate school.     

Composition of Cuticular Waxes on Osmunda regalis Fronds

The chemical composition of rodlet-shaped wax crystals on fronds of Osmunda regalis was analyzed. In all, 139 compounds belonging to 14 homologous series were detected in the surface extract. They included typical plant wax constituents: alkanes (C₂₅–C₃₃), alkyl esters (C₃₈–C₅₀), primary alcohols (C₂₂–C₃₂), secondary alcohols (C₂₇ and C₂₉), ketones (C₂₇–C₃₃), aldehydes (C₂₄–C₃₄), fatty acids (C₂₄–C₃₂), and -sitosterol. Additionally, bifunctional C₂₉ compounds (-diketone, ketols, diols) were identified. Nonacosan-10-one as the most abundant single compound, together with its bifunctional derivatives, is likely to form the wax crystals found on O. regalis fronds. Hence, a new type of wax crystals is defined morphologically and chemically. The occurrence of comparable wax aggregates on surfaces of higher plants is discussed.     

Isolation and identification of a sex attractant of a mushroom-infesting sciarid fly

A sciarid fly,Lycoriella mali (Fitch), is one of the most destructive pests to the commercial mushroom,Agaricus bisporus (Lange) Singer. Sanitation procedures and pesticide applications were ineffectual in controlling this pest. A supplemental pest control method employing sex pheromones was suggested since previous work indicated the presence of a sex attractant in the female. Diagnostic reactions performed on female extracts indicated saturated hydrocarbons as active components. The biologically most active fractions eluted from the gas chromatograph between standard hydrocarbons C₁₅ and C₂₂. Hydrocarbons C₁₅, C₁₆, C₁₇, and C₁₈ were isolated and identified via TLC, GC, and GC-MS. Male response to standard hydrocarbons C₁₅ to C₂₆ indicated that C₁₇ is a major attractant. Male response to varying amounts of C₁₇ indicated a preference for levels 10^–6g and 10^–9g.     

Sintering of MgO made from MgCl2

Conclusions The production parameters for a densely sintered magnesite powders made from MgO obtained from the thermal decomposition of MgCl₂ have been established. It is shown that the mechanical activation of MgO can be carried out in a vibromill for 10–20 min with an addition of a surface-active material (distillery waste or C₇-C₉ (fatty acids).Under pilot-plant conditions, using the process which has been developed, we obtained an MgO briquette of apparent density 3.20–3.33 g/cm³, an open porosity of 1.6–4.6%, and a MgO concentration of 97.9%. The magnesite and magnesite-chrome articles based on this briquette have excellent properties.Deceased.Translated from Ogneupory, No. 7, pp. 41–45, July, 1979.     

Solvent-free allylic oxidation of cycloolefins over mesoporous CrMCM-41 molecular sieve catalyst at 1 atm dioxygen

Oxidation of cycloolefins was effectively performed under aerobic (1 atm dioxygen) and mild solvent-free conditions using mesoporous CrMCM-41 molecular sieve catalyst. For instance, Cycloolefins (C₅–C₇) were selectively oxidized to the corresponding α,β-unsaturated ketones (for example, cyclohexene – 52.2% conversion and 71.2% selectivity) and cycloolefins (C₈–C₁₂) were oxidized to epoxides (for example, cis-cyclooctene – 50% conversion and >99% selectivity) at 323–353 K for 24 h. The catalytic activity over recycled catalyst remains nearly same.     

Direct evidence of intramolecular rearrangement in skeletal isomerization of n-butane over bifunctional catalysts

Mechanisms of skeletal isomerization of n-butane over bifunctional catalysts, Pt–Cs_2.5H_0.5PW₁₂O₄₀ and Pt-sulfated ZrO₂, as well as the corresponding solid acids were studied using 1,4-¹³C₂-n-butane. The isotopic distributions of the reactant and product were analyzed with field ionization mass spectrometry, by which the parent peak patterns were obtained. It was found that 1,4-¹³C₂-n-butane was selectively isomerized to ¹³C₂-isobutane over these catalysts in the presence of H₂ at 423–523 K, while the corresponding solid acids gave isobutane with binomial distributions of ¹³C. These results clearly demonstrate that the skeletal isomerization of n-butane proceeded mainly via a monomolecular path with intramolecular rearrangement on both the bifunctional catalysts, while it occurred through a bimolecular path with intermolecular rearrangement on the solid acids. This difference in reaction mechanism is reflected on that in the selectivity to isobutane.     

Defensive Role of Secretion of Ectal Mandibular Glands of the Wasp Polistes dominulus

Ectal mandibular glands of insects are exocrine glands localized in the anterior–lateral region of the head, close to the base of the mandibles. In social wasps, the gland is composed of secretory cells and a reservoir into which the secretion accumulates. At the time of emission the secretion flows onto a specialized cuticular area on the outside of the base of the mandibles. Secretion of Polistes dominulus is emitted only when wasps are greatly disturbed or in the presence of predators, and its function seems to be mainly defensive. Morphometric studies did not reveal any size differences between the glands of the queens and those of the workers. GC-MS analyses of the glands identified 32 compounds, mainly acids and aldehydes in the range C₂–C₁₈. The overall odor, caused by the mixture of aldehydes, is distinct. Workers do not respond strongly to the odor. The secretion probably serves as a warning signal to vertebrate predators.     

Double-layer capacitance and polarization potential of baked carbon anodes in cryolite-alumina melts

Baked carbon anodes with varying apparent densities and baking temperatures were tested in Na₃AlF₆–Al₂O_3(sat) melts at 1010° C. The double-layer capacitance (C _dl) was used as an indicator of the wetted surface area. For unpolarized anodes,C _dl increased with increasing time of immersion and reached a constant level after 1.5–2h. The values decreased with increasing polarization potential in the range 1–1.5 V positive to aluminium. TheC _dl of polished samples increased markedly during electrolysis, particularly at low current densities. No clear correlation was found betweenC _dl and apparent density. Semi-logarithmic plots of potential versus current could be divided into three segments. The lower two were linear, the ranges and slopes being 0.01–0.1 A cm^–2, 0.20–0.44 V per decade and 0.1–0.5 A cm^–2, 0.18–0.24 V per decade, respectively. At higher current densities the curves bent upwards. The current density corresponding to an overpotential of 0.5 V increased slightly with increasing apparent density, whereas the ohmic voltage drop. at constant current density decreased. The current densities were corrected for differences in wetted surface area on the basis of theC _dl data. The change in baking temperature from 970 to 1100°C had no appreciable effect on the overpotential, whereas samples baked at 1250°C showed a somewhat lower overpotential.     

Investigation of fibres based on rigid-chain polyamides by the wide-line nmr and ultrasonic acoustics

Conclusions -- A dependence of the second moment of the NMR line on the angle between the fibre axis and the magnetic field has been given; the structural coefficient C ₀, C ₂, and C ₄ have been calculated for fibres based on poly-p-phenyleneterephthalamide and poly-p-benzamide at temperatures of –196 and +20°C and for Kevlar-49, from –196 to +400°C.-- The intramolecular structural coefficients C ₀ ^im, C ₂ ^im, and C ₄ ^im have been calculated theoretically, and the orientation parameters and and the acoustic orientation factor f have been obtained, values for which indicate a high degree of orientation of the macromolecules in fibres.-- The smaller values of the second moment of the NMR line for PABI as compared with fibres based on PPTA in the temperature region 250–380°C indicate a more mobile structure for the PABI.-- In the range from –196 to +20°C thermal action leads to a more important change in the coefficient C ₀ for Kevlar-29 and Kevlar-49 as compared with PABI; this is apparently connected with thermal expansion in planes having a predominant concentration of van der Waals bonds for Kevlar-29 and Kevlar-49.Translated from Khimicheskie Volokna, No. 4, pp. 23–26, July–August, 1990.     

Volatile Components in Dorsal Gland Secretions of the White-Lipped Peccary, Tayassu pecari, from Bolivia

Secretions from the dorsal gland of male and female free-ranging adult white-lipped peccaries (Tayassu pecari) from Bolivia were analyzed by gas chromatography–mass spectrometry. Fifty compounds were identified, some provisionally. Secretions of both sexes contain saturated and unsaturated C₅–C₁₈ carboxylic acids as well as isomers of the diterpene springene. The females' secretions uniquely possess farnesyl esters of C₈ and C₁₀ carboxylic acids, whereas the males' secretions uniquely showed two compounds provisionally identified as monounsaturated C₁₆ lactones. Saturated high-molecular-weight esters of C₁₀ carboxylic acids are more abundant in the females' secretions than in those of the males. The secretions of both sexes also contain monoalkanoate esters of methylhydroquinone as major components.     

The synthesis and hydrolysis of dimethyl acetals catalyzed by sulfated metal oxides. An efficient method for protecting carbonyl groups

Sulfated metal oxides including SO₄ ^2–/ZrO₂, SO₄ ^2–/TiO₂, SO₄ ^2–/HfO₂, SO₄ ^2–/Fe₂O₃, SO₄ ^2–/SnO₂, and SO₄ ^2–/Al₂O₃ were highly efficient catalysts for the reaction of aldehydes and ketones with trimethyl orthoformate producing dimethyl acetals under mild reaction conditions. At room temperature, dimethyl acetal yields of 83–100% were obtained for the five carbonyl compounds chosen. These mesoporous solid acids also effectively catalyzed the hydrolysis of dimethyl acetal to regenerate the original carbonyl compounds in aqueous acetone. They not only provided an effective method for synthesizing dimethyl acetals of larger molecular size but also acted as a versatile catalyst for protecting and deprotecting carbonyl groups during organic synthesis.     

Resolution of Epoxydienes by Reversed-Phase Chiral HPLC and its Application to Stereochemistry Assignment of Mulberry Looper Sex Pheromone

Resolution of insect pheromonal cis-epoxydiene racemates derived from (Z,Z,Z)-3,6,9-trienes was examined with a reversed-phase chiral HPLC column. The results showed that a Chiralcel OJ-R column was suitable for separating the enantiomers having a C₁₇–C₂₃ unsaturated straight chain except for 9,10-epoxydienes with a C₂₁–C₂₃ chain. To determine the absolute configuration of the separated enantiomers, each of the optically active epoxydienes was hydrogenated over Pd-BaSO₄ and its behavior was examined on this chiral column by cochromatography with the corresponding chiral epoxy compound having a saturated chain, which was prepared via a Sharpless epoxidation reaction. This analysis showed that the dextrorotatory C₁₇–C₂₃ 3,4- and 6,7-epoxydienes and C₁₇–C₂₀ 9,10-epoxydienes with shorter R _ts possess (3S,4R)-, (6S,7R)-, and (9R,10S) configurations, respectively, and the levorotatory enantiomers with longer R _ts possess the opposite configuration. An abdominal tip extract of the mulberry looper, Hemerophila artilineata Butler (Lepidoptera: Geometridae: Ennominae), included (9S,10R)-(Z,Z)-cis-9,10-epoxy-3,6-octadecadiene as a main sex pheromone component. The synthetic (9S,10R)-9,10-epoxydiene, rather than its antipode, elicited strong antennal and behavioral responses from the male moths in electrophysiological and field tests.     

Catalytic oxidation of hydrocarbons over Co3O4 catalyst prepared by CVD

The total oxidation of C₂H₂, C₃H₆, C₃H₈, n-C₄H₈, n-C₄H₁₀ and i-C₄H₁₀ was studied in a monolithic flow reactor under temperature-programmed mode and highly diluted conditions. The non-catalytic combustion of the investigated hydrocarbons leads to a substantial formation of CO and traces of methane at intermediate temperatures. This drawback was suppressed upon the deposition of a thin layer of Co₃O₄ on the monolith and all investigated hydrocarbons tend to light off at 250–290 °C. The apparent activation energy was found to exhibit a linear correlation with the C–H bond dissociation energy, indicating that the C–H activation is still the rate-limiting step.     

Electrolytic oxidation of cuprocyanide electroplating waste waters under different pH conditions

The main purpose of this work was to investigate the electrolytic oxidation of cuprocyanide solution with various total cyanide to copper molar ratios ranging from 2.8 to 20 and under different pH conditions. In strong alkaline solution (pH12), cuprocyanide ions Cu(CN) _n ^/(n–1)– , wheren=2, 3 or 4, are directly electroxidized, and copper oxide precipitates on the anode. Cyanate ions, as well as nitrogen gas, were detected as the products and 0.30–0.43 g mol of total cyanide was destroyed per Faraday. For less alkaline solutions (pH<12), cuprocyanide ions first dissociated to free cyanide ions and then electroxidized. At a pH of 10.5–11.7, cyanate ion and brown azulmin polymer were produced in the anolyte. In the neutral solution (pH=7.0–8.6), carbonate and ammonium ions and azulmin were formed and 0.52–0.56 g mol of total cyanide was destroyed per Faraday. In weak acidic solution (pH=5.2–6.8), oxalate and ammonium ions and white oxamide were produced and 1.01–1.18 g mol of total cyanide were destroyed per Faraday.Nomenclature C _CN molar concentration of total cyanide (kmol m^–3) - C _Cu molar concentration of total copper (kmol m^–3) - C _d equivalent concentration of cyanide destroyed due to the formation of cupric oxide (kg m^–3) - C _f concentration of cyanide destroyed by dissociation of complex ion to free cyanide ion and then electroxidized (kg m^–3) - C _i initial concentration of total cyanide (kg m^–3) - C _t change of total cyanide concentration during electrolysis (kg m^–3) - F Faraday constant (96 487 C mol^–1) - K ₁,K ₂,K ₃ formation constant of dicyanocuprate, tricyanocuprate and tetracyanocuprate ions - R molar ratio of total cyanide concentration to total copper concentration (i.e.C _CN/C _Cu) - W weight of precipitates on electrodes or in anolyte (kg) - angle of incidence     

Contact angle of surfactant solutions on precipitated surfactant surfaces

In this study, the contact angle of a saturated aqueous surfactant solution onto the surface of a precipitate of that surfactant is investigated. Those precipitates include fatty acids (C₁₀, C₁₂, C₁₄, C₁₆, and C₁₈), sodium salts of fatty acids (C₁₄, C₁₆, and C₁₈), calcium salts of fatty acids (C₈, C₁₀, C₁₂, C₁₄, C₁₆, and C₁₈). On virgin surfaces, free fatty acids and calcium salts of fatty acids have advancing contact angles (θ_A) between 77 and 92°, with little dependence on alkyl chain length for C₁₂ and higher alkyl chains. The sodium salt of a fatty acid has a lower θ_A than the free fatty or the calcium salt of the soap. The calcium salt of dodecyl sulfate has a lower θ_A than the calcium salt of dodecanoic acid (θ_A = 46 vs. 82°), but the calcium salt of the 18-carbon hydrophobes showed nearly the same contact angle for the soap and the alkyl sulfate. Greasiness, or slipperyness, or a scummy feel of a precipitated surfactant does not necessarily correspond to a hydrophobic surface.