Synthesis of14C-propoxur (o-isopropoxyphenyl N-methylcarbamate-14C) insecticide

Propoxur (Baygon^®) is an insecticide with a broad spectrum of activity and a very low order of mammalian toxicity. Radiosynthesis of propoxur was performed by the reaction of acetyl-1¹⁴C chloride and sodium azide to produce methyl isocyanate which then reacted with o-isopropoxyphenol at 100°C. A two compartment reaction tube with a break seal was utilized. Chromatographic procedures for isolating the N-methylcarbamates from their reaction mixtures are reported. Acetyl-1–¹⁴C chloride was prepared from thionyl chloride and sodium acetate-1–¹⁴C. Grignard reaction between methyl iodide and carbon –14 dioxide yielded acetic acid –¹⁴C which was neutralized by sodium hydroxide solution to give sodium acetate 1-¹⁴C.     

Glycosylation of Bovine Serum Albumin with D-[<Superscript>14</Superscript>C]-Glucose

Certain parameters of the Maillard reaction between bovine serum albumin (BSA) and D-[¹⁴C]-glucose were investigated.__________Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 275–277, May–June, 2005.     

Δ<Superscript>8(14)</Superscript>-14α-deoxy- and 14α-deoxy-14α-hydroperoxyecdysteroids

Δ⁸⁽¹⁴⁾-14α-deoxy- and 14α-deoxy-14α-hydroperoxyecdysteroids were synthesized, the reduction of Δ⁸⁽¹⁴⁾-14α-deoxy-20-hydroxyecdysone diacetonide at treatment with complex hydrides of alkali metals was investigated, and the stereochemistry of the obtained 6-hydroxy derivative and its acetate was established.     

Oxidation of sodium (2-14C) acetate with alkaline permanganate

The mechanism and kinetics of the oxidation of sodium acetate with permanganate in alkaline and neutral media, has been investigated using (2-¹⁴C) acetate. The reaction is first order both with respect to permanganate and acetate ions. The initial second order rate constants depend linearly on the square of the hydroxide ion concentration. Arrhenius acitvation energy of the oxidation reaction carried out in 12M NaOH is 24.0 kcal/mole in the temperature interval 50–100°C. The mechanism of the principal path leading to the oxalate formation and the mechanism of the side reaction resulting in the carbon dioxide production has been proposed and discussed.     

Degradation of Sucrose,Glucose and Fructose in Concentrated Aqueous Solutions Under Constant pH Conditions at Elevated Temperature

ABSTRACT

The degradation of sucrose can decrease sucrose yield, reduce the efficiency of sugar factory and refinery processes, and effect end product quality. Characterization of sucrose degradation under modeled industrial processing conditions will underpin further technological improvements. Effects of constant reaction pH on sucrose degradation were investigated using simulated industrial model systems (100 °C; 65 °Brix [% dissolved solids]; N₂; 0.05-3 mol NaOH titrant; 8 h), with the use of an autotitrator. Reaction pH values ranged from 4.40 to 10.45. Polarimetry and ion chromatography with integrated pulsed amperometric detection (IC-IPAD) were used to quantify sucrose degradation and first-order reaction constants were calculated. Minimum sucrose degradation occurred between pH 6.45 - 8.50, with minimum color formation between pH's 4.40 - 7.00. Polarimetry, often used in U.S. sugar factories and refineries to monitor chemical sucrose losses, was shown not to be viable to measure sucrose degradation under alkaline conditions, because of the formation of fructose degradation products with an overall positive optical rotation. For comparison, fructose and glucose (80 °C; 65 °Brix; N₂; 3 mol NaOH; 2 h) were also degraded at constant pH 8.3 conditions. For sucrose, fructose, and glucose, formation of organic acids on degradation was concomitant with color formation, indicating they are probably produced from similar reaction pathways. For the glucose and fructose degradation reactions, color and organic acid formation also were highly correlated (R²>0.966) with changes in optical rotation values, confirming that these compounds are formed from similar reaction pathways.     

Determination of14C in spent HTGR fuel elements

Spent HTGR-fuel spheres were analysed chemically to determine their¹⁴C content.¹⁴C is mainly (∼96%) produced in the graphite matrix of the fuel. About 75% of the¹⁴C is derived from¹⁴N. More than 99% of¹⁴C is released as CO₂ during the combustion of the fuel elements. Assuming no¹⁴C retention, the maximum body burden at the critical region of a 50000 MW HTGR reprocessing plant will be ∼ 70 mrem/a. Paper presented at the 9th Radiochemical Conference, Piestany, CSSR.     

Thermodynamics of the conversion of aqueous glucose to fructose

The thermodynamics of the conversion of aqueous glucose to fructose has been investigated using both heat conduction microcalorimetry and high pressure liquid chromatography (HPLC). The reaction was carried out in both aqueous Tris/HCl buffer and in aqueous phosphate buffer in the pH range 7–8 using the enzyme glucose isomerase and the cofactors CoCl₂ and MgSO₄. The temperature range over which this reaction was investigated was 298.15–358.15 K. We have found that the enthalpy of reaction is independent of pH over the range investigated. A combined analysis of both the HPLC and microcalorimetric data leads to the following results at 298 15 K:ΔG° = 349 ± 53 J mol^-1, ΔH° = 2.78 ± 0.20 kJ mol^-1, and ΔC _p ^° = 76 ± 30 J mol^-1 K^-1. The stated uncertainties are based upon an analysis of both the random and systematic errors inherent in the measurements. Comparisons are made with literature data. The percent conversion of glucose to fructose has been calculated for the temperature range 300–373.15 K.     

Determination of biogenic amines by RPHPLC with fluorescent detection after derivatization with 2-(9-carbazole)ethyl chloroformate (CEOC)

Summary The use of 2-(9-carbazole)ethyl chloroformate (CEOC) for pre-column derivatization of biogenic amines (BA) has been tested for the first time. The reagent reacts completely with BA within 3 min at ambient temperature in acetonitrile solution to form stable derivatives that are readily analyzed by reversed-phase HPLC. Study of the derivatization conditions revealed derivatization yields to be excellent in borate buffer over the pH range 9.0–10.0. Maximum yields were obtained by use of a three- to fourfold molar excess of reagent. The reaction is extremely tolerant of common buffer salts, no decrease in reaction yield is discernible in well-buffered samples. The emission maximum for the CEOC-derivatives is 360 nm (λ _ex = 293 nm). All the derivatives fluoresced strongly and direct injection of the reaction mixture was possible, with no significant disturbance from the major fluorescent reagent degradation by-products, 2-(9-carbazole)ethanol (CEOC-OH) and bis-(2-(9-carbazole)ethyl) carbonate (CEOC)₂. Separation of the derivatized BA by high-performance liquid chromatography with gradient elution was tested on a Hypersil BDS C18 column. Excellent response linearity was observed over the concentration range from 0.25 to 94.6 μmol L⁻¹ for the labeled BA. Detection limits were 117–840 fmol at a signal-to-noise ratio of 3∶1. Analysis of BA in a shrimp sauce extract was conducted to demonstrate the applicability of the technique to real sample matrixes; results were satisfactory.     

Synthesis of 3β-Hydroxy[21-14C]-5β-pregn-8(14)-en-20-one from Chenodeoxycholic Acid

3β-Hydroxy[21-¹⁴C]5β-pregn-8(14)-en-20-one ( 17 ) was prepared from chenodeoxycholic acid ( 1a ). The synthetic sequence involved: (i) degradation of the bile-acid side chain to an etianic acid; (ii) formation of the 8(14)-double bond; (iii) inversion of the configuration at C(3); (iv) construction of the acetyl side chain at C(17) with the required isotopic label at C(21). Structures of all described products were confirmed by chemical and spectroscopic (IR, ¹H-NMR, ¹³C-NMR, MS) methods.     

Synthesis, properties, and the crystal structure of the complex Cp2Yb(DAD)

The diazadiene complex of trivalent ytterbium, Cp₂Yb(DAD) (1) (DAD=Bu^t−N=CH−CH=N−Bu^t) was prepared according to three different procedures, namely, by oxidation of Cp₂Yb(THF)₂ with diazadiene in THF, by the reaction of Cp₂YbCl with DAD²⁻Na⁺ ₂ taken in a ratio of 2∶1, and by the reaction of Cp₂YbCl(THF) with DAD²⁻Na⁺ ₂ taken in a ratio of 1∶1. Complex1 was characterized by microanalysis, IR spectroscopy, magnetochemistry, and X-ray diffraction analysis. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 384–386, February, 1999.     

A rapid automated method for wine analysis based upon sequential injection (SI)-FTIR spectrometry

A new process control methodology for the simultaneous determination of sugars, alcohols and organic acids in wine based on multivariate evaluation of mid-IR transmission spectra of wine samples is presented. In addition to ethanol several lower level wine components (glucose, fructose, glycerol, citric-, tartaric-, malic-, lactic- and acetic acid) were determined. To establish a multivariate calibration model a set of 72 calibration solutions was prepared and measured, using a novel, fully automated sequential injection (SI) system with Fourier transform infrared (FTIR) detection. The resulting spectra were evaluated using a partial least square (PLS) model. The developed PLS model was then applied to the analysis of real wine samples containing 79–91 g L^–1 ethanol, 5.9–8.1 g L^–1 glycerol, 0.4–6.9 g L^–1 glucose, 1.5–7.5 g L^–1 fructose, 0.3–1.6 g L^–1 citric acid, 1.0–1.7 g L^–1 tartaric acid, 0.02–3.2 g L^–1 malic acid, 0.4–2.8 g L^–1 lactic acid and 0.15–0.60 g L^–1 acetic acid, yielding results which were in good agreement with those obtained by an external reference method (HPLC-IR). The short analysis time (less than 3 min) together with high reproducibility makes the newly developed method applicable to process control and screening purposes (average of the standard deviations calculated from four repetitive measurements of six different real samples: ethanol: 0.55 g L^–1, glycerol: 0.037 g L^–1, glucose: 0.056 g L^–1, fructose: 0.036 g L^–1, citric acid: 0.020 g L^–1, tartaric acid: 0.010 g L^–1, malic acid: 0.052 g L^–1, lactic acid: 0.012 g L^–1 and acetic acid: 0.026 g L^–1). Received: 21 January 1998 / Revised: 5 March 1998 / Accepted: 6 March 1998     

Mild template synthesis in the CoII-dithiooxamide-glyoxal system in cobalt(II) hexacyanoferrate(II) gelatin-immobilized matrices

Complexation processes in a cobalt(II) hexacyanoferrate(II) gelatin-immobilized matrix under the action of aqueous solutions containing dithiooxamide H₂N−C(S)−C(S)−NH₂ and glyoxal HOC−CHO at pH>10 were studied. Under these conditions, mild template synthesis occurs to form a Co^III chelate with the (N,N,S,S)-ligand,viz. 2,7-dithio-3,6-diazaoctadiene-3,5-dithioamide-1,8, with a metal to ligand ratio of 1∶1, where dithiooxamide and glyoxal act as ligand synthons. The reaction mechanism is discussed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1999–2004, October, 1999.     

Determination of <Superscript>3</Superscript>H and <Superscript>14</Superscript>C in the Dry Active Wastes (DAW) generated from the Light Water Reactors (LWR) by a wet oxidation method

³H and ¹⁴C Measurements of the dry active waste (DAW), such as the cotton, paper, and vinyl, generated from a nuclear power plant (NPP) were conducted with wet oxidation using open vessel equipment based on simulation results. The recovery efficiency with the simulated samples was around 93% with a relative standard deviation (RSD) of 1–3%. A liquid scintillation counter (LSC) was used for counting and adjusted to a quenching correction curve. The counting value was evaluated for the minimum detectable activity (MDA), which was found to be about 4 × 10⁻¹ Bq/g for ³H and 2 × 10⁻² for ¹⁴C when approximately 5 g of the samples were measured. The measured DAW samples for the cotton, paper, and vinyl generated from NPP achieved of RSD values of 25, 25, and 60%, respectively, for ³H and 0–50% for ¹⁴C.     

Formation and structure of diruthenium complexes Ru2(CO)6−n (PPh3) n {μ-C(CH=CHPh)C(Ph)C(CH=CHPh)C(Ph)} (n=1, 2)

Ruthenium carbonyl triphenylphosphine complexes Ru₂(CO)_6−n (PPh₃) _n {μ-C(CH=CHPh)C(Ph)C(CH=CHPh)C(Ph)} (n=1, 2) were obtained by the reaction of complex Ru₂(CO)₆{μ-C(CH=CHPh)C(Ph)C(CH=CHPh)C(Ph)} containing the ruthenacyclopentadiene moiety with PPh₃ in refluxing toluene. The complexes were characterized by IR and by¹H,¹³C, and³¹P NMR spectroscopy, and by X-ray analysis. The monophosphine derivative is identical to the complex formed by fragmentation of the Ru₃(CO)₈(PPh₃){μ-C(CH=CHPh)C(Ph)C(CH=CHPh)C(Ph)} cluster and contains the PPh₃ ligand at the ruthenium atom of the ruthenacyclopentadiene moiety. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1836–1843, September, 1998     

Observation of a Doppler broadening of the 4438 keV gamma-line of12C in processes12C(n,n′γ)12C and9Be(α, nγ)12C

A Doppler broadening is described of the 4438 keV spectral gamma-line observed by means of a Ge(Li) detector during the deexcitation of nuclei of¹²C in an inelastic scattering¹²C(n, n′γ)¹²C using an²⁴¹Am−Be source as well as during the reaction⁹Be(α, nγ)¹²C taking place in the Am−Be source. The FWHM of the spectral line is equal to (90±4) keV in the latter reaction and (64±8) keV in the former process. Experimental values agree well with theoretical ones. Presented at the Instrumental Activation Analysis Conference, IAA 79, June 4–8, 1979, Klučenice, Czechoslovakia.     

Pilot determinations of 3H and 14C in gaseous releases from Kozloduy nuclear power plant

Methods for routine assessment of ³H and ¹⁴C content in gaseous releases from ventilation stacks of Kozloduy Nuclear Power Plant (Bulgaria) were developed. Technique for correction of incomplete desorption of tritium from exposed silica gel was proposed. The distribution and the concentrations of both nuclides in various chemical forms were constantly monitored for a period of 1 year. The results for annual normalized gaseous discharges were assessed for the fifth unit at 173 GBq/(GW.a) for ³H and 369 GBq/(GW.a) for ¹⁴C, while for the sixth unit—³H—98 GBq/(GW.a) and ¹⁴C—289 GBq/(GW.a).     

Study on the production of formaldehyde-14C by direct reduction of14CO2 with LiAlH4

A vial technique was developed for the synthesis of formaldehyde-¹⁴C from¹⁴CO₂ in an ether solution of lithium aluminium hydride. The yield of formaldehyde (40–50%) was achieved by optimization of the reaction parameters.     

The development of nuclear microprobe techniques for the spatial determination of13C and13C/12C ratios

Sensitive and selective nuclear reaction methods have been sought for the nuclear microprobe measurement of the spatial distributions of¹³C and¹³C/¹²C ratios. The¹³C(α, n)¹⁶O reaction, with neutron detection, is the most selective for¹³C, and has a sensitivity of ca. 100 ppm. The reactions¹³C(d, p)¹⁴C and¹²C(d, p)¹³C, with proton detection, are the most sensitive for the simultaneous measurement of¹³C and¹²C, with detection limits of 30 and 2 ppm respectively. Less sensitive alternative reaction pairs are;¹³C(³He, p)¹⁵N and¹²C(³He, p)¹⁴N;¹³C(d, nγ)¹⁴N and¹²C(d, pγ)¹³C;¹³C(³He, pγ)¹⁵N and¹²C(³He, pγ)¹⁴N. The conditions governing their use, particularly light element interferences, are detailed.     

Addition of diazocyclopropane generatedin situ to acrylic acid derivatives and transformations of resulting functionally substituted spiro(pyrazolinecyclopropanes)

The reaction of diazocyclopropane generatedin situ with acrylonitrile or methyl acrylate to give 1∶1, 1∶2, and 2∶1 cycloadducts was carried out. The products resulting from 1,3-dipolar cycloaddition and subsequent isomeriation,viz., 3-cyano- and 3-methoxycarbonylspiro(2-pyrazoline-5,1′-cyclopropanes), isolated in the first step in ∼70% yield, react in an alkaline solution with the above acrylates or diazocyclopropane as C(3)-nucleophiles to give the corresponding 3-(2′-cyanoethyl)-, 3-(2′-methoxycarbonylethyl)-, or 3-(cyclopropylazo)-1-pyrazolines. The thermal deazotization of these pyrazolines to spiropentane derivatives was investigated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 532–539, March, 1997.     

Differential determination of203Hg and14C or35S in double labelled biological samples

The differential determination of²⁰³Hg and¹⁴C or³⁵S in double labelled biological samples is presented. The biological samples were mineralized with 70% HClO₄ and 30% H₂O₂ in minivals MILLI-6. The γ-activity of²⁰³Hg was measured on a well scintillation counter. The total activity, due to²⁰³Hg and¹⁴C or³⁵S, was measured by the liquid scintillation technique after addition of Aquasol into the same vials. The method of external standard channel ratio was used for standardization. Very good recoveries were obtained: 100±0.7% for²⁰³Hg and 94.6–101.0% for¹⁴C and³⁵S. This method could be used for other β, γ and β-active nuclides with similar β-spectra.