Nonglyceride complex of the seed oil ofOnopordum acanthium

Extraction of the comminuted seeds has yielded an oil from which have been isolated: C₃₃-C₂₅, C₁₈ and C₁₇ paraffinic hydrocarbons, C_18:1, C_18:2, C_18:3, C_17:1, C_17:2 and C_17:3 olefinic hydrocarbons, ethyl esters of C_32:0, C_31:0, C_30:0, C_29:0, and C_28:0 fatty acids, sterols with molecular weights of 414, 412, and 400, and the alcohols -amyrin and lupeol with their natural acetates. Extraction of the uncomminuted seeds has shown that the paraffinic hydrocarbons, ethyl esters, and alcohol acetates pass into the oil from the husks of the seeds. This is the first time that the C_31:0 and C_29:0 fatty acids have been detected as natural compounds, and it is the first time that the ethyl esters of C₃₄, C₃₃, C₃₂, C₃₁, and C₃₀ fatty acids have been isolated from seed oils of higher plants.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 612–615, September–October, 1979.     

Nonglyceride complex of the seed oil ofOnopordum acanthium

Extraction of the comminuted seeds has yielded an oil from which have been isolated: C₃₃-C₂₅, C₁₈ and C₁₇ paraffinic hydrocarbons, C_18:1, C_18:2, C_18:3, C_17:1, C_17:2 and C_17:3 olefinic hydrocarbons, ethyl esters of C_32:0, C_31:0, C_30:0, C_29:0, and C_28:0 fatty acids, sterols with molecular weights of 414, 412, and 400, and the alcohols α-amyrin and lupeol with their natural acetates. Extraction of the uncomminuted seeds has shown that the paraffinic hydrocarbons, ethyl esters, and alcohol acetates pass into the oil from the husks of the seeds. This is the first time that the C_31:0 and C_29:0 fatty acids have been detected as natural compounds, and it is the first time that the ethyl esters of C₃₄, C₃₃, C₃₂, C₃₁, and C₃₀ fatty acids have been isolated from seed oils of higher plants.     

Polymer bound pyrrole compounds,VII: Xanthobilirubinic acid esters and amides from an insoluble,polystyrene-supported precursor

Summary A series of xanthobilirubinic acid (XBR) esters (i.e.,1c to1p) and amides (2a–2c) have been prepared by a procedure involving detachment of the chromophore previously ester-bound to a functionalized, insoluble polystyrene (1b). Detachment is achieved by treatment with the respective alcohol in aqueous alkali or with the amines, yielding directly the corresponding esters or amides. With primary, short-chained alcohols the ester yields are high (60% forn-C₄H₉-OH to 99% for C₂H₅-OH), but decrease rapidly with chain length (40% forn-C₁₀H₂₁-OH and 0% forn-C₁₆H₃₃-OH). The same trends are observed with the amines. These results are interpreted in terms of an (increasingly) unfavourable entropic interaction between the polymer matrix to which the chromophore is bound and the (growing) alcohol chain. The impairment by the long chained nucleophile to reach the transesterification center could also contribute, and, for the most lipophylic alcohols, their low solubility in aqueous alkali is an additional drawback. With secondary and tertiary alcohols, no ester is obtained, in agreement with a B_AC2 mechanism involving a tetrahedral intermediate.

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Polymergebundene Pyrrolverbindungen, 7. Mitt.: Darstellung von Xanthobilirubinsäureestern und-amiden, ausgehend von einer unlöslichen polystyrolgebundenen Vorstufe

Zusammenfassung Unlösliche, durch eine Estergruppe an Polystyrol gebundene Xanthobilirubinsäurederivate liefern mit Alkoholen die monomeren Ester (1c–1p), mit Aminen die monomeren Amide (2a–2c). Die Ausbeuten für primäre kurzkettige Alkohole sind hoch (n-C₄H₉-OH: 60%, C₂H₅-OH: 99%), mit steigender Kettenlänge sinken sie rasch (n-C₁₀H₂₁-OH: 40%,n-C₁₆H₃₃-OH: 0%). Denselben Trend beobachtet man bei Aminen. Die Ergebnisse werden durch eine zunehmend ungünstige entropische Wechselwirkung zwischen Chromophor an der Matrix und Alkohol interpretiert. Durch die steigende Kettenlänge des Alkohols könnte auch aus räumlichen Gründen die Annäherung des Nucleophils an das Reaktionszentrum erschwert werden. Die geringe Löslichkeit der höheren lipophilen Alkohole in wäßrigem Alkali wirkt sich ebenfalls ungünstig auf den Reaktionsverlauf aus. Für sek. und tert. Alkohole wird keine Reaktion erhalten, wie es für einen B_AC2-Mechanismus mit tetraedrischem Zwischenprodukt zu erwarten ist.

     

Reduction of NO by C1-C4 hydrocarbons on cation-exchanged zeolites

New data are presented for the reduction of nitric oxide by C₁-C₄ hydrocarbons (alkanes and olefins) on active copper, cerium, and cobalt zeolite catalysts both with and without oxygen in the reaction mixture. The following hydrocarbon reactivity series were obtained. Olefins: C₄H₈ > C₃H₆ > C₂H₄. Alkanes: C₄H₁₀ > C₃H₈ > CH₄.L. V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine, 31 Prospekt Nauki, 252039 Kiev, Ukraine. Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 32, No. 4, pp. 238–242, July–August, 1996. Original article submitted September 14, 1995.     

Hydrocarbomethoxylation of C5-C9 olefins with formic acid and methanol under conditions of catalysis with phosphoric acid

Conclusions The methyl esters of branched carboxylic acids containing quaternary and tertiary C atoms in the-position, together with a small amount of the corresponding carboxylic acids, are formed during the hydrocarbomethoxylation of the straight-chain C₅-C₉ olefins at atmospheric pressure in the presence of concentrated H₃PO₄.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 454–456, February, 1973.     

Determination of the Critical Micelle Concentration of Surfactant in Aqueous Solution by Twisted Intramolecular Charge Transfer Probe DMABN

With p-N,N-dimethylaminobenzonitrile (DMABN) as a probe, the variations of the intensity of its second fluorescence emission (I_a) and the corresponding characteristic wavelength (λ_a) with the surfactant concentration (c), here the examined surfactants (C₁₂TABr, SDS, C₁₂E₂₃, and C₁₂-3-C₁₂·2Br), were measured by Hitachi F4500 fluorescence spectrophotometer. The results showed that both the break points on the I_a–c curve and the minimum of the derivative variation corresponding to the λ_a–c curve agreed very well with the critical micelle concentration (cmc) of the surfactant in aqueous solution as measured by surface tension technique. Due to strong aggregation of C₁₂-3-C₁₂·2Br in aqueous solution, the information about loose micellar structure could be obtained by its λ_a–c curve.     

(π-Cyclopentenyl)(π-cyclopentadienyl)nickel: A novel catalyst for the conversion of ethylene to 1-butene and n-hexenes

(π-Cyclopentenyl)(π-cyclopentadienyl)nickel, (h⁵-C₅H₅)Ni(h³-C₅H₇), is a novel, highly active, unicomponent catalyst for the conversion of ethylene to n-butenes and n-hexenes at 145–150° C. At high conversions of ethylene (70–90%), the dimeric product (80–86% yield) contains a high percentage (90–82%) of 1-butene. Experimental evidence is presented which strongly indicates that the cyclopentadienyl group remains bonded to the nickel during catalysis while the cyclopentenyl group is labile. A possible mode of activation is the reversible elimination of cyclopentadiene from (h⁵-C₅H₅)N₁(h³-C₅H₇) to generate π-cyclo pentadienylnickel hydride as a catalytically active intermediate. An improved synthesis of the title compound (70% yield) by direct hydrogenation of nickelocene is also reported.     

Effect of doping with small amounts of nickel on the catalytic properties of zirconium dioxide in the hydrogenation of carbon monoxide

Doping of zirconium dioxide with small amounts of nickel (0. 03 %) caused a several fold increase in the rate of formation of C₂-C₄ olefins, particularly isobutene, from CO and hydrogen. The combined catalyst ZrO₂-Ni/SiO₂ showed increased selectivity with respect to olefins in comparison with the Ni/SiO₂ catalyst.Science Prosp., 31. Translated from Teoreticheskiya i Éksperimental'naya Khimiya, Vol. 32, No. 6, 353–357, November-December, 1996. Original article submitted March 1, 1996.     

Synthesis of mixtures of aromatic and aliphatic hydrocarbons from CO and H2 over Fe catalysts

It was determined that 8.2% Fe-1–4.5% K/Al ₂ O ₃ catalysts are active in the synthesis of C ₁ -C ₆ aliphatic and C ₆ -C ₈ aromatic hydrocarbons (AH) from mixtures of CO:H ₂ =1:2–2:1. The AH content in the liquid reaction products is 90%. A discussion of the synthesis schemes for AH is presented.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 117334. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 3, pp. 546–551, March, 1992.     

Phytochemical Study on Moghania Strobilifera

n-C₂₆H₅₄, n-C₂₇H₅₆, n-C₂₈H₅₈, n-C₂₉H₆₀, n-C₃₀H₆₂, n-C₃₁H₆₄, n-C₃₂H₆₆, n-C₃₃H₆₈, stigmasterol, β-sitosterol and two unidentified compounds: a saturated ester (mp 79-81°C); an unsaturated alcohol (mp 87-88°C) were isolated from the whole herb of Moghania strotilifera.     

Die Umsetzung von Diphenylphosphinigsäurechlorid mit Natriumsalzen von aromatischen Sulfinsäuren zu Diphenylphosphinsäure-S-arylestern

Zusammenfassung Die Umsetzung von Diphenylphosphinigsäurechlorid mit Alkalisalzen aromatischer Sulfinsäuren führt unter Reduktion am Schwefel, Oxydation am Phosphor und Ausbildung einer Bindung zwischen Phosphor und Schwefel, zu Diphenylthiophosphinsäure-S-arylestern: (C₆H₅)₂P(O)–S–Ar (Ar=C₆H₅, 4-CH₃C₆H₄, 4-ClC₆H₄, 2-Cl-5-CH₃-C₆H₃, 2-C₁₀H₇). Die besten Ausbeuten (40–85%) wurden mitDMF als Lösungsmittel erhalten. Aliphatische Phosphinigsäurechloride geben keine Bindung zwischen P und S. Ebenso tritt keine Umsetzung ein, wenn im Säurechlorid eine P–O-Struktur vorliegt. Auch die Umsetzung von (C₆H₅)₂PCl und (C₆H₅)₂P(O)Cl mit Sulfonsäuren anstelle der Sulfinsäuren führt zu keiner P–S-Verknüpfung. Diese Phosphor-Schwefel-Bindung in den Thiophosphinsäure-S-estern stellt die schwächste Stelle im Molekül dar, da ein hydrolytischer, oxydativer oder reduktiver Angriff diese Bindung wieder löst.

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Reaction of diphenylchlorophosphine with alkali salts of aromatic sulfinic acids leads to diphenylthiophosphinates; reduction occurs at the sulfur atom, oxidation at the phosphorus atom and a bond between phosphorus and sulfur is formed: (C₆H₅)₂P(O)–S–Ar, Ar=C₆H₅, 4-CH₃C₆H₄, 2-ClC₆H₄, 2-Cl-5-CH₃-C₆H₃, 2-C₁₀H₇. The best yields were obtained in dimethyl formamide as solvent. With aliphatic chlorophosphines no bond formation beetween sulfur and phosphorus occurred. Similarly no reaction was observed, when a phosphorus atom in a higher state of oxidation was present, as for example in diphenylphosphonylchloride. Also, no reaction took place when sulfonic instead of sulfinic acids were used. The weakest bond found to exist in the diphenylthiophosphinates was the P–S-linkage, which readily undergoes hydrolytic, oxidative or reductive cleavage.

     

Force constant calculations of the LAM-1 modes ofn-alkanes and their substituted α-Monohalo- and α,ω-dihalo- species in their extended zig-zag planar configurations as found in urea inclusion compounds

Force constants were determined for the C₈, C₁₀, C₁₂ and C₁₄ series ofn-alkanes C _n H_{2n + 2} using an approximate SVFF calculation and observed LAM = 1 wave numbers. In this calculation the hydrogen atoms were neglected and only the carbon backbone chain and terminal atoms were considered; this was valid since only low-frequency vibrations were under consideration. Using force constant transfer, the wavenumbers of the LAM = 1 accordion modes for the analogous -C_n H_2n + 1 X and ,-C_n H_2nX₂ species, where X = C1, Br or I were calculated. For -chloroalkanes and ,-dichloroalkanes, them = 1 accordion modes are calculated to be in the 220–130 cm^–1 and 200–120 cm^–1 regions, respectively. For the bromo- and iodo-analogues them = 1 accordion modes are calculated to be in the 200–100 cm^–1, 150–90 cm^–1 and in the 170–100, 135–80 cm^–1 regions, respectively.     

Gas Electron Diffraction and Quantum-Mechanical Study of Dimethyloxalate

The geometrical structure and conformation of dimethyloxalate, CH₃OC(O)–C(O)OCH₃, have been studied by gas electron diffraction (GED) and quantum-chemical calculations (MP2 and B3LYP methods with 6-31G* and cc-pVTZ basis sets). The GED analysis with a dynamic model (T = 323 K) results in a mixture of two planar conformers, anti (C_2h symmetry) and syn (C_2v symmetry) orientation of the two C=O bonds. The energy difference between these conformers is 0.02(0.18) kcal/mol and barrier to internal rotation around the C–C bond is 0.44(0.41) kcal/mol. The CH₃ groups occupy synperiplanar positions with respect to the C=O bonds. The following main geometrical parameters for the anti conformer (Å and degrees) have been derived: r_g(C–C) = 1.532(3), r_g(C=O) = 1.203(2), r_g(C_sp3–O) = 1.436(3), r_g(C_sp2–O) = 1.333(3), (C_sp2–C_sp2–O) = 111.9(1.9), (C_sp2–O–C_sp3) = 116.3(1.6), (O–C= O) = 127.0(1.8).This paper is devoted to the 75th anniversary of gas electron diffraction method.     

Magnetische Untersuchungen an Komplexen von La(III), Pr(III) und Nd(III) mitSchiffschen Basen

Specific magnetic susceptibilities (_s) of several newly synthesized chelates of some of the lanthanons [La(III), Pr(III) and Nd(III)] are reported. These derivatives are of the general type,Ln(O-i-C₃H₇)_3–n (C₆H₅CHNRO) _n [where,Ln=La(III), Pr(III) or Nd(III);n=1 or 2 and R=CH₂CH₂, CH₂CHCH₃ or C₆H₄] and have been prepared by the reaction of the alkoxides of the lanthanons withSchiff bases such as benzylidene-2-hydroxyethylamine (C₆H₅CHNCH₂CH₂OH), benzylidene-2-hydroxy-n-propylamine (C₆H₅CHNCH₂CHOHCH₃) and benzylidene-o-aminophenol (C₆H₅CHNC₆H₄OH) in different molar relations in dry benzene.The resulting crystalline derivatives are non-volatile, light to deep yellow or blackish in colour. These tend to polymerize on keeping as shown by their insoluble nature and higher melting points, the polymerisation possibly occurring by the intermolecular coordination through oxygen atoms as reported earlier¹.UsingGouy method², the bis-isopropoxy mono-Schiff base and mono-isopropoxy bis-Schiff base complexes of La(III) have been shown to be diamagnetic, with _s values being in the range of –0.32 to –0.45×10^–6 and –0.39 to –0.55×10^–6 c.g.s. units at 305 K respectively.In the remaining derivatives, Pr(O-i-C₃H₇)_3–n (C₆H₅CH NRO) _n and Nd(O-i-C₃H₇)_3–n (C₆H₅CHNRO) _n (where,n=1 or 2 and R=CH₂CH₂, CH₂CHCH₃ or C₆H₄) the magnetic moment values range between 3.25 to 3.32 and 3.30 to 3.33 _B respectively indicating their paramagnetic nature.     

Synthesis ofcloso-3,3-(η3,η2-tricyclo[5.2.1.02,6]deca-4, 8-diene-3-yl)-1-(hydroxymethyl)-3,2,1-dicarbollylrhodium and the crystal structure of its dinier with the O-H...Rh bond

Protonation of the [closo-3,3-(⁴-C₁₀H₁₂)-1-(CH₂OH)-3,1,2-RhC₂B₉H₁₀]^– PPN⁺ (C₁₀H₁₂ — dicyclopentadiene, PPN⁺ — bis(triphenylphosphine)iminium cation) at the ethylene bond of the norbornene moiety yields the neutralcloso-3,3,3-(-C₁₀H₁₃)-1-(CH₂OH)-3,1,2-RhC₂B₉H₁₀ with an agostic C-H...Rh bond. On prolonged storage in EtOH, the latter complex is converted intocloso-3,3-(^3,2-C₁₀H₁₁)-1-(CH₂OH)-3,1,2-RhC₂B₉H₁₀ with -allylolefinic type coordination. Its crystal structure as dimeric aggregates with O-H...O and O-H...Rh bonds was determined by X-ray diffraction.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 776–778, April, 1995.     

Adsorption of n-Butanol from Aqueous Solutions on a Bi–Ga Electrode

Curves of the differential capacitance at the Bi–Ga/H₂O interface in 0.05 M Na₂SO₄ solutions with different concentrations of n-C₄H₉OH are obtained by a bridge method at 420 Hz and 32°C. Adsorption parameters of n-C₄H₉OH, determined by a regression analysis of these curves, are compared with relevant data for mercury and partially fused polycrystalline bismuth (pBi). That the adsorption behavior of organic molecules at Hg differs from that at pBi and Bi–Ga is due not to their different hydrophilicity but to a different physical interaction water–electrode. The reason for this phenomenon can be an unequal spread of electron density beyond the ionic cores of Hg and Bi. These notions are corroborated by the fact that the Bi–Ga data fit overall correlation dependence between the electronic capacitance of different electrodes in the absence of a chemisorption interaction metal–water and the adsorbability of the n-C₄H₉OH molecules on them.     

Molecular structure and conformational composition of 1-Chlorobutane, 1-Bromobutane,and 1-Iodobutane as determined by gas-phase electron diffraction and ab initio calculations

Gas-phase electron diffraction (ED), together with ab initio molecular orbital calculations, have been used to determine the structure and conformational composition of 1-chlorobutane, 1-bromobutane, and 1-iodobutane. These molecules may in principle exist as mixtures of five different conformers, but only three or four of these were observed in gas phase at temperatures of the ED experiments, 18C, 18C, and 23C, respectively. The observed conformational compositions (1-chlorobutane, 1-bromobutane, and 1-iodobutane) were AA (13 ± 12%, 21 ± 14%, 19 ± 17%), GA (60±13%, 33±32%, 17±31%), AG (12±16%, 8±12%, <1%), and GG (12 ±16%, 38± 34%, 64±31%). A and G denotesanti andgauche positions for the X-C₁-C₂-C₃ (X=Cl, Br, I), and the C₁-C₂-C₃-C₄ torsion angles. The results for the most important distances (r _g) and angles () from the combined ED/ab initio study for the GA conformer of 1-chlorobutane, with estimated 2 uncertainties, arer(C₁-C₂)=1.519(3)å,r (C₂-C₃)=1.530(3) å,r (C₃-C₄)=1.543(3) å,r (C₁-Cl)=1.800(4) å, <C₁C₂C₃=114.3(6), <C₂C₃C₄=112.0(6), <CCCl=112.3(5). The results for the GA conformer of 1-bromobutane arer (C₁-C₂)=1.513(4) å,r (C₂-C₃)=1.526(4) å,r (C₃-C₄)=1.540(4) å,r(C₁-Br)=1.959(8) å, <C₁C₂C₃=115.3(11), <C₂C₃C₄=112.8(11),<CCBr=112.1(14). The results for 1-chlorobutane and 1-bromobutane are compared with those from earlier electron diffraction investigations. The results for the GA conformer of 1-iodobutane arer (C₁-C₂)=1.506(5) å,r (C₂-C₃)=1.518(5) å,r (C₃-C₄)=1.535(5) å,r (C₁-I)=2.133(11) å, <C₁C₂C₃=116.8(15), <C₂C₃C₄=115.3(15), <CCI=110.2(14). Differences in length between the different C-H bonds in each molecule, between the different C-C bonds, between the different CCH angles, and between the different CCC angles were kept constant at the values obtained from the ab initio calculations.     

Steric and Electronic Influences in Os3(CO)11(PR3) Structures

The structures of Os₃(CO)₁₁(PR₃) with R=F, OPh, Et, p-C₆H₄Me, o-C₆H₄Me, p-C₆H₄(CF₃) and C₆H₁₁, and with PR₃=P(OCH₂)₃CMe have been determined. The Os–Os bond lengths in these compounds are compared to the Os–Os lengths for the other structures of Os₃(CO)₁₁(PR₃) clusters reported in the literature. In most cases, the Os–Os bond length remote from the P ligand [range, 2.8666(4)–2.9044(4) Å] and that in the pseudo-trans position [range, 2.8712(5)–2.900(1) Å] show little variation as the steric and electronic properties of the P ligand are varied. The Os–Os length cis to PR₃ shows more variation [range, 2.879(1)–2.9429(4) Å] and is sensitive to both the size and the -donor/-acceptor properties of the PR₃ ligand: larger or better donor PR₃ ligands cause an increase in the Os–Os bond length. The Os–P distances [range, 2.15(2)–2.478(1) Å] show a similar dependence on the steric and electronic properties of the PR₃ ligand.     

Quantum-Chemical Study of Alkyl Carbenium Ions in 100% Sulfuric Acid

A quantum-chemical study of neutral and protonated monoalkyl sulfates RHSO₄and [RH₂SO₄]⁺(where R = CH₃, C₂H₅, iso-C₃H₇, and tert-C₄H₉) is carried out. Calculations are performed using the Hartree–Fock method in the 6-31G** and 6-31++G** basis sets taking into account electron correlation according to the Müller–Plesset perturbation theory MP2/6-31+G*//6-31+G*. Protonated tert-butyl sulfate was also calculated by the DFT B3LYP/6-31++G** method. It was found that monoalkyl sulfates are covalent compounds, and the complete abstraction of alkyl carbenium ions from them has substantial energy cost: 196.4, 161.7, 150.8 and 136.0 kcal/mol, respectively. Protonated methyl and ethyl sulfates are also covalent compounds according to the calculation. They have lower but still high energies of heterolytic dissociation (65.0 and 33.5 kcal/mol, respectively). The energy of R⁺abstraction from protonated isopropyl sulfate is much lower: 23.6 kcal/mol. The main covalent state and the ion–molecular pair, which is a carbenium ion [C(CH₃)₂H]⁺solvated by the H₂SO₄molecule, have about the same energy. The ground state of protonated tert-butyl sulfate corresponds to the ion–molecular complex [C(CH₃)⁺ ₃H₂SO₄] with still lower energy of carbenium ion [C(CH₃)₃]⁺abstraction, which is equal to 10.0 kcal/mol. Calculation according to the DFT B3LYP/6-31++G** method shows the absence of a minimum for the protonated tert-butyl sulfate with a covalent structure on the potential energy surface.     

Determination of n-paraffinic structure in petroleum fraction by infrared spectroscopy

Summary The characteristic strong absorption infrared band near 720–725 cm^–1 of an open chain methylene group of the type (CH₂) _n (n = 4 or more) has been used to estimate the number of n-paraffinic methylene groups in an average molecule of saturates, urea adductables and non-adductables of various gas-oil and vacuum gas oil fractions. The method was developed by computing the average absorptivity at 725 cm^–1 of several pure n-paraffins (C₁₄-C₃₂). Although the interference due to the aromatic C — H band at 740 cm^–1 disturbs the estimation of shorter chains, it is seen from the data on adductables and non-adductables that the estimation can be done in long chain paraffins even in the presence of aromatics.

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Bestimmung von n-Paraffinstrukturen in Erdölfraktionen mit Hilfe der Infrarot-Spektroskopie

Zusammenfassung Die charakteristische starke IR-Absorptionsbande der paraffinischen Methylengruppe des Typs (CH₂) _n (n = 4 oder mehr) bei 720–725cm^–1 wurde zur Bestimmung der Anzahl von Methylengruppen in einem durchschnittlichen Molekül von gesättigten Kohlenwasserstoffen, Harnstoffprodukten sowie Nicht-Addukten verschiedener Gasöl- und Vakuum-Gasöl-Fraktionen benutzt. Das Verfahren wurde durch Berechnung der durchschnittlichen Extinktion bei 725 cm^–1 von mehreren reinen n-Paraffmen (C₁₄-C₃₂) entwickelt. Wenn auch die Bestimmung kürzerer Ketten durch die aromatische C — H-Bande bei 740 cm^–1 gestört wird, so ergibt sich doch aus den Werten für Addukte und Nicht-Addukte, daß die Bestimmung bei langkettigen Paraffinen selbst in Gegenwart von Aromaten durchgeführt werden kann.