scholarly journals Preparation of Triacetoneamine, I

1977 ◽  
Vol 32 (3) ◽  
pp. 328-337 ◽  
Author(s):  
G. Sosnovsky ◽  
M. Konieczny
Keyword(s):  
Gas Chromatography ◽  
Calcium Chloride ◽  
Room Temperature ◽  
Mesh Size ◽  
Mesityl Oxide ◽  
Diacetone Alcohol ◽  
Weight Yield ◽  
Optimized Conditions

The preparation of triacetoneamine (1) by the condensation of acetone with ammonia in the presence of calcium chloride at room temperature is investigated. In addition to 1, acetonin (8), diacetone alcohol (4), mesityl oxide, and diacetoneamine (7) are formed during the reaction. The progress of the reaction is monitored by gas chromatography. The effects of the extent and the rate of stirring, the amount of ammonia introduced on the critical first day of the reaction, and the mesh size and the amount of calcium chloride on the purity and weight yield of 1 are studied. The yield of 1 is maximized by recovery of the unreacted acetone. The reaction at room temperature under optimized conditions is described.

scholarly journals Preparation of Triacetoneamine, II

1977 ◽  
Vol 32 (3) ◽  
pp. 338-346 ◽  
Author(s):  
G. Sosnovsky ◽  
M. Konieczny
Keyword(s):  
Gas Chromatography ◽  
Calcium Chloride ◽  
Ammonium Chloride ◽  
Weight Yield ◽  
Optimized Conditions ◽  
Yield And Purity

The preparation of triacetoneamine (1) by the condensation of acetone with ammonia in the presence of calcium chloride is investigated. The progress of the reaction is monitored by gas chromatography. The effects of added ammonium chloride, the total amount of ammonia introduced, and the temperature of the reaction on the weight yield and purity of 1 are investigated. The optimized conditions for the preparation of 1 at 59 °C are described.

Off-Line Direct Deposition Gas Chromatography/Surface-Enhanced Raman Scattering and the Ramifications for On-Line Measurements

2005 ◽  
Vol 59 (11) ◽  
pp. 1305-1309 ◽  
Author(s):  
David A. Heaps ◽  
Peter R. Griffiths
Keyword(s):  
Gas Chromatography ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Room Temperature ◽  
Warm Up ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
On Line ◽  
Enhanced Raman Scattering ◽  
Moving Liquid

Surface-enhanced Raman spectra (SERS) of molecules separated by gas chromatography (GC) were measured off-line by condensing the analyte on a moving, liquid-nitrogen-cooled ZnSe window on which a 5 nm layer of silver had been formed by physical vapor deposition. After the components that eluted from the chromatograph had been deposited, the substrate was allowed to warm up to room temperature and transferred to the focus of a Raman microspectrometer where the spectrum of each component was measured. Band intensities in the spectrum of 3 ng of caffeine prepared in this way were approximately the same as in the spectrum of bulk caffeine. By making some logical assumptions, it was shown that identifiable GC/SERS spectra of 30 pg of many molecules could be measured over a 300 cm−1 region in real-time and that if an optimized substrate were used the minimum identifiable quantity could be reduced to 1 pg or less.

Zinc carbonate recovery from brass melting slag

2021 ◽  
Vol 98 ◽  
pp. 14-18
Author(s):  
Thao Nguyen Thi ◽  
◽  
Nam Pham Ky ◽  
Ngoc Tran Vu Diem
Keyword(s):  
Sulfuric Acid ◽  
High Purity ◽  
Room Temperature ◽  
Ph Value ◽  
Zinc Carbonate ◽  
Leaching Solution ◽  
Optimized Conditions ◽  
Melting Slag

Brass melting slag (20.38 wt.% Zn) was leached in sulfuric acid with concentration of (50 + 80) g/l H2SO4, leaching temperature of (30 + 60) °C for (30 + 120) min. The optimized conditions for 94.16% Zn extraction from brass melting slag were found as 70 g/l H2SO4, room temperature and 90 min. The leaching solution was purified by removal of Fe through Fe(OH)3 precipitation when adding ZnO to adjust pH value of 5. The solution was continuously cemented by Zn metal at 60 °C for 60 min to obtain Cu metal with high purity of 99 wt.% Cu. The purified solution with 37.64 g/l Zn was modified by Na2C03 to have pH value of about 6 and precipitation of ZnC03 (94.14 %).

scholarly journals VALIDATION AND ANALYSIS OF DIALLYL DISULFIDE AND DIALLYL TRISULFIDE IN GARLIC (ALLIUM SATIVUM L.) USING GAS CHROMATOGRAPHY

2020 ◽  
pp. 163-166
Author(s):  
HARMITA HARMITA ◽  
HERMAN SURYADI ◽  
LIDWINA DEVIANI LIKASA
Keyword(s):  
Gas Chromatography ◽  
Allium Sativum ◽  
Limit Of Detection ◽  
Diallyl Disulfide ◽  
Diallyl Trisulfide ◽  
Ionization Detector ◽  
Limit Of Quantification ◽  
Flame Ionization ◽  
Precision Limit ◽  
Optimized Conditions

Objective: The purpose of this research was to optimize and validate a method for measuring the levels of diallyl disulfide (DADS) and diallyl trisulfide(DATS) in garlic and single clove garlic.Methods: The analysis was performed using gas chromatography (GC) equipped with an HP-1 column and a flame ionization detector. The initialcolumn temperature was set at 140°C and increased at 1°C/min to 180°C. The injector and detector temperatures were set to 200°C, the carrier gasflow rate was 0.80 mL/min, and the injection volume was 1.0 μL. The optimized conditions of analysis were then validated which included selectivity,linearity, accuracy, precision, limit of detection (LOD), and limit of quantification (LOQ).Results: Using the validated assay and a concentration range of 0.5–20 μg/mL, the coefficient of correlation (r) for DADS was 0.9999 and the LODand LOQ for DADS were 0.3063 μg/mL and 1.0210 μg/mL, respectively. Using the validated assay and a concentration range of 0.5–20 μg/mL, thecoefficient of correlation for DATS was 0.9999 and the LOD and LOQ for DATS were 0.1986 μg/mL and 0.6621 μg/mL, respectively. The percentage ofrecovery was in the range of 98.05–101.76% and coefficient of variation ≤ 2%.Conclusion: This GC method accurately measures the levels of DADS and DATS in garlic.

scholarly journals Practical Determination of the Solubility Parameters of 1-Alkyl-3-methylimidazolium Bromide ([CnC1im]Br, n = 5, 6, 7, 8) Ionic Liquids by Inverse Gas Chromatography and the Hansen Solubility Parameter

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1346 ◽  
Author(s):  
Qiao-Na Zhu ◽  
Qiang Wang ◽  
Yan-Biao Hu ◽  
Xawkat Abliz
Keyword(s):  
Gas Chromatography ◽  
Ionic Liquids ◽  
Physicochemical Properties ◽  
Solubility Parameter ◽  
Room Temperature ◽  
Inverse Gas Chromatography ◽  
Retention Volume ◽  
Solubility Parameters ◽  
Hansen Solubility Parameter ◽  
Hansen Solubility

The physicochemical properties of four 1-alkyl-3-methylimidazolium bromide ([CnC1im]Br, n = 5, 6, 7, 8) ionic liquids (ILs) were investigated in this work by using inverse gas chromatography (IGC) from 303.15 K to 343.15 K. Twenty-eight organic solvents were used to obtain the physicochemical properties between each IL and solvent via the IGC method, including the specific retention volume and the Flory–Huggins interaction parameter. The Hildebrand solubility parameters of the four [CnC1im]Br ILs were determined by linear extrapolation to be δ 2 ( [ C 5 C 1 im ] Br ) = 25.78 (J·cm−3)0.5, δ 2 ( [ C 6 C 1 im ] Br ) = 25.38 (J·cm−3)0.5, δ 2 ( [ C 7 C 1 im ] Br ) =24.78 (J·cm−3)0.5 and δ 2 ( [ C 8 C 1 im ] Br ) = 24.23 (J·cm−3)0.5 at room temperature (298.15 K). At the same time, the Hansen solubility parameters of the four [CnC1im]Br ILs were simulated by using the Hansen Solubility Parameter in Practice (HSPiP) at room temperature (298.15 K). The results were as follows: δ t ( [ C 5 C 1 im ] Br ) = 25.86 (J·cm−3)0.5, δ t ( [ C 6 C 1 im ] Br ) = 25.39 (J·cm−3)0.5, δ t ( [ C 7 C 1 im ] Br ) = 24.81 (J·cm−3)0.5 and δ t ( [ C 8 C 1 im ] Br ) = 24.33 (J·cm−3)0.5. These values were slightly higher than those obtained by the IGC method, but they only exhibited small errors, covering a range of 0.01 to 0.1 (J·cm−3)0.5. In addition, the miscibility between the IL and the probe was evaluated by IGC, and it exhibited a basic agreement with the HSPiP. This study confirms that the combination of the two methods can accurately calculate solubility parameters and select solvents.

Headspace Sampling and Gas Chromatographic Determination of Styrene Migration from Food-Contact Polystyrene Cups into Beverages and Food Simulants

1981 ◽  
Vol 64 (5) ◽  
pp. 1122-1130 ◽  
Author(s):  
Sandra L Varner ◽  
Charles V Breder
Keyword(s):  
Gas Chromatography ◽  
Room Temperature ◽  
Detection Limits ◽  
Chromatographic Determination ◽  
Headspace Sampling ◽  
Ionization Detector ◽  
Migration Studies ◽  
Flame Ionization ◽  
And Storage

Abstract Migration studies using coffee, tea, water, and 8% ethanol were conducted with various types of foodcontact polystyrene cups. Study conditions simulated filling and storage at room temperature and hot-filling or pasteurization above 150°F (65.6°C). The quantity of styrene migrating was determined by headspace sampling and gas chromatography (GC). The GC column was 6% Carbowax 20M on Chromosorb 101 with quantitation via a flame ionization detector. Detection limits ranged from 3 to 10 ppb in various liquids. The method and results of the migration studies are presented.

Preliminary Studies on Weathering of Chlordane Residues

1965 ◽  
Vol 48 (5) ◽  
pp. 952-954
Author(s):  
Alfred D Thruston
Keyword(s):  
Gas Chromatography ◽  
Quantitative Determination ◽  
Plant Extracts ◽  
Room Temperature ◽  
Agricultural Products ◽  
Qualitative And Quantitative ◽  
Chromatographic Peaks ◽  
The Many ◽  
Ppm Level

Abstract The qualitative and quantitative determination of chlordane residues on raw agricultural products has been best achieved by gas chromatography techniques. While good recoveries (90–100% at the 0.1 ppm level) have been obtained from plant extracts with added standard chlordane, weathered chlordane residues show changes in number and size of gas chromatographic peaks. Chlordane at the 50 µg level, when exposed to the air at room temperature over a period of time, showed progressive decomposition and loss of the many components that make up chlordane.

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