Search results for "Propene"

Comparison between catalytic and catalytic photo-assisted propene hydration by using supported polyoxometalate.

2012

A study on the catalytic perfomances of H3PW12O40 supported on TiO2 and SiO2 for propene hydration in the presence and in the absence of UV light

2012

1-METHYLCYCLOPROPENE DELAYS RIPENING AND IMPROVES POSTHARVEST QUALITY OF WHITE FLESH LOQUAT

2015

The ethylene inhibitor 1-methylcyclopropene (1-MCP) delayed ripening and improved postharvest fruit quality of loquat (Eriobotrya japonica Lindl.). 1-MCP was used on the white flesh sub-acid loquat cultivars ‘Claudia’ and ‘BRT20’ to evaluate the possible effect on fruit ripening and to prevent negative effects of cold storage, like internal browning and flesh leatheriness. 1-MCP was applied at 2°C for 20 h and concentrations of 1 and 5 μl L-1. After 1-MCP treatment fruit were held at 2°C for 7, 14, and 21 days and then moved to 18°C for 5 days. Fruit flesh firmness, titratable acidity (TA), total soluble content (TSS), weight loss, internal browning and flesh leatheriness were evaluated at …

Density Functional Theory Study on Propane and Propene Adsorption on Pt(111) and PtSn Alloy Surfaces

2011

Density functional theory calculations were performed to investigate the adsorption of propane, propene, and C and H atoms on Pt and PtSn surfaces employing the revised Perdew–Burke–Ernzerhof (RPBE) and vdW-DF functionals. Propane adsorption was found to be mediated by van der Waals interactions without significant site preference on any of the studied surfaces. The adsorption characteristics of propene are different: On the Pt(111) and Pt3Sn(111) surfaces, propene adsorption is covalent, and the molecule prefers a di-σ site to a π site. Alloying Pt(111) with Sn leads to weaker adsorption owing to geometric and relaxation effects, whereas electronic effects are found to be small. On the PtS…

Influence of gel composition in the synthesis of MoVTeNb catalysts over their catalytic performance in partial propane and propylene oxidation

2010

[EN] MoVTeNb mixed oxides catalysts have been prepared by a slurry method with different molar compositions (Mo/Te ratio from 2 to 6 and Nb/(V + Nb) ratio from 0 to 0.7) in the synthesis gel leading to different crystalline phases distribution and catalytic behaviour in the partial oxidation of both propane and propylene to acrylic acid. Chemical analysis indicates that the composition of samples before and after the heat-treatment changes, especially the Te-content, since a significant amount of Te is lost during the heat-treatment step when the amount of oxalate (from niobium oxalate) increases in the synthesis gel. Thus, the nature of the crystalline phases and the catalytic performance …

Extension of Walsh's rules to more general systems

1972

It is demonstrated that location of hydrogen atoms within bonding distance of a simple triatomic molecule can alter the order of energy levels relative to that of the parent system without significantly changing the behavior of the orbital energies under geometrical variation. As a result the ground state electronic configurations of H n AB2 systems often differ from those of triatomics with the same number of electrons and this fact is shown to be directly responsible for the existence of such distinctive geometrical structures as those possessed by cyclopropane, cyclopropyl and allyl cations and cyclopropene. Thus the familiar prescription of Walsh's rules which states that isoelectronic …

ALTERNATIVES TO METHYL BROMIDE IN STRAWBERRY CULTIVATION

2009

Inhibition of fatty acid delta 6- and delta 5-desaturation by cyclopropene fatty acids in rat liver microsomes.

1993

delta 6-Desaturation of linoleic acid and delta 5-desaturation of dihomo-gamma-linolenic acid were measured in liver microsomes from rats fed fresh Baobab seed oil containing cyclopropene fatty acids (malvalic acid and sterculic acid) or heated Baobab seed oil practically devoid of these fatty acids or control oil. The presence of cyclopropene fatty acids in the fresh Baobab oil diet highly depressed both desaturations, but delta 6- more than delta 5-desaturation. The decreased capacity of microsomes to desaturate was reflected in the lower arachidonic acid content in microsomal phospholipids from rats fed this oil. However it was also lower in rats fed heated oil although in vitro delta 6-…

Keggin heteropolyacid H3PW12O40 supported on different oxides for catalytic and catalytic photo-assisted propene hydration

2013

Catalytic and catalytic photo-assisted hydration of propene to form 2-propanol in gas–solid regime at atmospheric pressure and 85 1C were carried out by using a heteropolyacid (POM) supported on different oxides. Binary materials were prepared by impregnation of H3PW12O40 on different commercial and home prepared supports (TiO2, SiO2, WO3, ZrO2, ZnO, Al2O3). Some of the composites were active both for catalytic and catalytic photo-assisted reactions. The Keggin type POM was completely and partially degraded, when supported on ZnO and Al2O3, respectively, and these binary solids always resulted as inactive for both catalytic and catalytic photo-assisted reactions. The supported Keggin POM sp…

Effect of 1-methylcyclopropene on ripening of melting flesh peaches and nectarines

2004

Abstract 1-Methylcyclopropene (1-MCP), an ethylene action inhibitor, was applied to early season, melting flesh stone fruit to try to extend their shelf life. ‘Almog’ and ‘Oded’, two white flesh peaches, and ‘April Glow’, a yellow flesh nectarine, were tested. Application of 1-MCP was at both 20 and 0 °C for 5, 10 and 20 h and at concentrations from 0.5 to 20 μl l −1 . When treated at 0 °C the fruits were stored for 5 days before removal to 20 °C for ripening. 1-MCP slowed fruit softening in a concentration and time dependent manner, extending the period before the fruits became over-soft. The inhibition of softening was greater when fruits were treated and held at 20 °C than if they were t…