Impact of fuel vapor pressure on emissions of non-methane volatile organic compounds from transport vehicles Wpływ prężności par benzyny na emisję nie-metanowych lotnych związków organicznych z pojazdów transportowych

2016 ◽  
Vol 1 (5) ◽  
pp. 151-154
Author(s):  
Stanisław Kruczyński
Keyword(s):  
Volatile Organic Compounds ◽  
Vapor Pressure ◽  
Organic Compounds ◽  
Fuel Vapor ◽  
Volatile Organic

scholarly journals Quantitative structure-property relationship studies for the prediction of the vapor pressure of volatile organic compounds

2019 ◽  
Vol 84 (12) ◽  
pp. 1405-1414
Author(s):  
Mounia Zine ◽  
Amel Bouakkadia ◽  
Leila Lourici ◽  
Djelloul Messadi
Keyword(s):  
Regression Analysis ◽  
Volatile Organic Compounds ◽  
Linear Regression ◽  
Vapor Pressure ◽  
Multiple Linear Regression ◽  
Organic Compounds ◽  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Test Set ◽  
Volatile Organic

A theoretical model (QSPR) using multiple linear regression analysis for predicting the vapor pressure (pv) of volatile organic compounds (VOCs) has been developed. A series of 51 compounds were analyzed by multiple linear regression analysis. First, the data set was separated arbitrarily into a training set (39 chemicals) and a test set (12 chemicals) for statistical external validation. A four-dimensional model was developed using as independent variables theoretical descriptors derived from Dragon software when applying the GA (genetic algorithm)?VSS (variable subset selection) procedure. The obtained model was used to predict the vapor pressure of the test set compounds, and an agreement between experimental and predicted values was verified. This model, with high statistical significance (R2 = 0.9090, Q2 LOO = 0.8748, Q2 ext = 0.8307, s = 0.24), could be used adequately for the prediction and description of the log pv value of other VOCs. The applicability domain of MLR model was investigated using a William?s plot to detect outliers and outsides compounds.

scholarly journals Volatile and Non-Volatile Organic Compounds Stimulate Oviposition by Aphidophagous Predators

Insects ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 683
Author(s):  
Eric W. Riddick
Keyword(s):  
Molecular Weight ◽  
Volatile Organic Compounds ◽  
Vapor Pressure ◽  
Organic Compounds ◽  
Egg Production ◽  
United States Department ◽  
Oviposition Stimulants ◽  
Molecular Weights ◽  
Production Ratio ◽  
Volatile Organic

Introduction: Evidence that volatile organic compounds (VOCs) and non-VOCs stimulate oviposition by aphidophagous predators is scattered throughout the literature. The objectives of this review are to (1) compile records indicating that VOCs and non-VOCs are responsible for oviposition stimulation, (2) calculate an egg production ratio (EPR) for stimulated predators, and (3) determine if EPR is correlated with vapor pressure and molecular weight of active compounds. Methods: The USDA (United States Department of Agriculture), National Agricultural Library, online digital catalog system was used to retrieve abstracts, then the full text of manuscripts on oviposition stimulants for predators. Oviposition-stimulating VOCs and non-VOCS were tabulated with molecular weights and vapor pressure estimates. EPRs were calculated for stimulated coccinellids, syrphids, and chrysopids. Results: Both VOCs and non-VOCs stimulated oviposition behavior by coccinellids and syrphids, but not chrysopids. EPR was greatest for syrphids. Two VOCs, (E)-β-farnesene and 3-methyl-2-butenal, stimulated very high EPR values by the syrphid Episyrphusbalteatus. Regardless of predator taxa, EPR was negatively and positively correlated with molecular weight and vapor pressure, respectively. Conclusions: Syrphids (rather than coccinellids or chrysopids) produce more eggs in response to VOCs. Organic compounds with low-to-moderate molecular weights and moderate-to-high vapor pressures might be most effective oviposition stimulants for aphidophagous predators.

Separation of Volatile Organic Compounds from Water by Pervaporation

MRS Bulletin ◽  
1999 ◽  
Vol 24 (3) ◽  
pp. 50-53 ◽  
Author(s):  
R.W. Baker
Keyword(s):  
Volatile Organic Compounds ◽  
Vapor Pressure ◽  
Organic Compounds ◽  
Driving Force ◽  
Liquid Mixtures ◽  
Vapor Condensation ◽  
Gas Pressure ◽  
Vapor Pressures ◽  
Volatile Organic ◽  
The Difference

Pervaporation is a membrane process used to separate liquid mixtures. Separation is achieved by a combination of evaporation and membrane permeation. As a result, the process offers the possibility of removing dissolved volatile organic compounds (VOCs) from water, dehydrating organic solvents, and separating mixtures of components with close boiling points or azeotropes that are difficult to separate by distillation or other means.A schematic diagram of the pervaporation process is shown in Figure 1. In the example shown, the feed liquid is a solution of toluene in water which contacts one side of a membrane that is selectively permeable to toluene. The permeate, enriched in toluene, is removed as a vapor from the other side of the membrane. The driving force for the process is the difference in the partial vapor pressures of each component in the feed liquid and the permeate gas. This driving force can be increased by raising the temperature of the feed liquid to increase its vapor pressure or by decreasing the permeate gas pressure. The permeate gas pressure can be adjusted by using a vacuum pump, but industrially the most economical method is to cool and condense the vapor. Condensation spontaneously generates a vacuum. The permeate vapor pressure is then determined by the temperature of the permeate condenser and the composition of the permeate liquid generated by cooling and condensing the permeate vapor.Pervaporation membranes are made by coating a thin layer of selective polymer material onto a microporous support.

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