Determination of Vapor Pressure of Chemical Compounds: A Group Contribution Model for an Extremely Large Database

2012 ◽  
Vol 51 (20) ◽  
pp. 7119-7125 ◽  
Author(s):  
Farhad Gharagheizi ◽  
Ali Eslamimanesh ◽  
Poorandokht Ilani-Kashkouli ◽  
Amir H. Mohammadi ◽  
Dominique Richon
Keyword(s):  
Vapor Pressure ◽  
Chemical Compounds ◽  
Group Contribution ◽  
Large Database ◽  
Group Contribution Model

MOLECULAR WEIGHTS FROM MICRO QUANTITIES OF MATERIALS

1949 ◽  
Vol 27b (3) ◽  
pp. 151-157 ◽  
Author(s):  
I. E. Puddington
Keyword(s):  
Molecular Weight ◽  
Vapor Pressure ◽  
Chemical Compounds ◽  
Unknown Compound ◽  
Molecular Weights ◽  
Pure Solvent ◽  
Unknown Substance ◽  
The Difference

A method is proposed for the determination of the molecular weight of chemical compounds in which the unknown substance may be used successfully m quantities of 1 mgm. or less. The method depends on the accurate measurement of the difference in vapor pressure between a solution of the unknown compound and the pure solvent, and this is accomplished with a modified mercury U-tube manometer. The results presented indicate that the difference between the experimental and theoretical molecular weights is of the order of 2%. Determinations require from two to three hours and the sample may be recovered.

Changes of some sewage sludge parameters prepared with an ultrasonic field

1997 ◽  
Vol 36 (11) ◽  
pp. 101-106 ◽  
Author(s):  
January Bien ◽  
Lidia Wolny
Keyword(s):  
Sewage Sludge ◽  
Microscopic Analysis ◽  
Chemical Compounds ◽  
Ultrasonic Field ◽  
Water Removal ◽  
Vacuum Filter ◽  
Additional Criterion ◽  
New Methods ◽  
Sludge Conditioning

Studies of sewage sludge conditioning by ultrasonic field concentrate on determination of the increase of water removal effect, which depends on kind of sludge and chemical compounds used in the dewatering process. An attempt was made to find new methods of sludge preparation before dewatering. Tests presented here focused on digested and difficult dewatered sludge. The sludge was dewatered on a vacuum filter after conditioning with polyelectrolytes and the ultrasonic field. The microscopic analysis was an additional criterion to evaluate changes in the sludge structure after preparation. The polyelectrolyte dose of 3 mg/g d.m. sonicated within 15 sec. resulted in the 50% decrease of sludge volume. Results presented confirmed our previous experiences, concerning the relation between conglomerates of sludge and the effect of dewatering.

Determination of Agarwood oil’s significant chemical compounds using principal component analysis

2020 ◽  
Author(s):  
Mohamad Hushnie Haron ◽  
Mohd Nasir Taib ◽  
Nurlaila Ismail ◽  
Nor Azah Mohd Ali ◽  
Saiful Nizam Tajuddin
Keyword(s):  
Principal Component Analysis ◽  
Principal Component ◽  
Chemical Compounds ◽  
Component Analysis ◽  
Significant Chemical

scholarly journals A group contribution model for determining the sublimation enthalpy of organic compounds at the standard reference temperature of 298K

2013 ◽  
Vol 354 ◽  
pp. 265-285 ◽  
Author(s):  
Farhad Gharagheizi ◽  
Poorandokht Ilani-Kashkouli ◽  
William E. Acree ◽  
Amir H. Mohammadi ◽  
Deresh Ramjugernath
Keyword(s):  
Organic Compounds ◽  
Group Contribution ◽  
Reference Temperature ◽  
Sublimation Enthalpy ◽  
Group Contribution Model

Determination of Bioactive Components of 60°С Volatiles from Cinnamomum camphora Branches by TD-GC/MS

2011 ◽  
Vol 230-232 ◽  
pp. 852-856
Author(s):  
Qing Li ◽  
Dang Quan Zhang ◽  
Qi Mei Liu ◽  
Kuan Peng
Keyword(s):  
Chemical Compounds ◽  
Chemical Components ◽  
Cinnamomum Camphora ◽  
Bioactive Components ◽  
Industrial Materials ◽  
Analytical Result ◽  
Main Components

The chemical components of helium volatiles from the fresh branches of Cinnamomum camphora were studied by TD-GC/MS. The analytical result by 60°С-based TD-GC/MS showed that 55 peaks were obtained from the helium volatiles from the fresh branches of Cinnamomum camphora and 53 chemical compounds were identified. The results showed that the main components were as: Bicyclo[2.2.1]heptan-2-one, 1,7,7-trimethyl-, (1R)- (15.4328%), 1,3-Benzodioxole, 5-(2-propenyl)- (14.881%), Tricyclo[2.2.1.0(2,6)]heptane, 1,7-dimethyl-7-(4-methyl-3-pentenyl)-, (-)- (12.694%), p-menth-1-en-8-ol (9.832%), Bicyclo[2.2.1]heptane, 2-methyl-3-methylene-2-(4-methyl-3- pentenyl)-, (1S-exo)- (6.143%), 1,6,10-Dodecatrien-3-ol, 3,7,11-trimethyl- (5.365%), Bicyclo[3.1.1] hept-2-ene, 2,6-dimethyl-6-(4-methyl-3-pentenyl)- (4.527%), Naphthalene, 1,2,3,5,6,8a- hexahydro-4,7-dimethyl-1-(1-methylethyl)-, (1S-cis)- (4.129%), 3-Cyclohexen-1-ol, 4-methyl-1- (1-methylethyl)- (2.965%), Borneol (2.627%), Bicyclo[2.2.1]heptan-2-ol, 1,7,7-trimethyl-, acetate, (1S-endo)- (2.586%), Copaene (2.534%), 1,6,10-Dodecatriene, 7,11-dimethyl-3-methylene-, (Z)- (1.612%), (-)-Isosativene (1.121%), etc. The analytical result suggested that the helium volatiles from the fresh branches of Cinnamomum camphora could be used as industrial materials of biomedicines and spicery.

Validasi dari Spektrofotometri UV-Vis dan Kandungan Total Flavonoid Ekstrak Etanol dari Akar Alang-Alang (Imperata cylindrica) dan Daun Pegagan (Centella asiatica) Anita Puspa Widiyana

2021 ◽  
Vol 3 (2) ◽  
pp. 126-136
Author(s):  
Anita Puspa Widiyana ◽  
Keyword(s):  
Chemical Constituents ◽  
Centella Asiatica ◽  
Ethanol Extract ◽  
Chemical Compounds ◽  
Imperata Cylindrica ◽  
Total Flavonoid ◽  
Analysis Method ◽  
Flavonoid Content ◽  
Validation Testing

Validation as a quality control for the content of chemical compounds from natural ingredients. One of the chemical constituents is the flavonoids which are found in the Imperatacylindrica roots and Centella asiatica leaves. This study aims to ensure the analysis method meets the requirements and determines the levels of flavonoids. The research stages included extraction, validation and determination of total flavonoid. Extraction was carried out by immersing dry simplicia in 96% ethanol solvent for 3x24 hours. The solvent is evaporated using a rotary evaporator until a thick extract is formed. Validation testing includes linearity, accuracy, precision, LOD and LOQ. Determinationof the total flavonoid was carried out by measuring the absorption at a maximum wavelength of 428.2 nm. The validation results includethe correlation coefficient (R) of 0.998, precision % RSD <2 %, %accuracy 99,53-97,98%, LOD 3.02ppm and LOQ 9.15 ppm. The total flavonoid of the ethanol extract of Imperata cylindrica roots was 36.39 ± 0.08 mg/g QE and Centella asiatica leaves was 102.10 ± 0.08 mg/g QE. The conclusion is that the method used met the validation requirements and the total flavonoid content of the ethanol extract of Centella asiatica leaves was higher than Imperata cylindrica roots

Determination of the Vapor Pressure and Evaporation Enthalpy of CeO2 Nano-Fuels Based on Isothermogravimetry

2021 ◽  
Vol 43 (1) ◽  
Author(s):  
Qian Ji ◽  
Deqing Mei ◽  
Chao Sun ◽  
Zongning Zhu ◽  
Dongmei Guo
Keyword(s):  
Vapor Pressure ◽  
Evaporation Enthalpy
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