An insight into regioselectivity in the transformation through a ruthenacycle

2020 ◽  
Vol 44 (5) ◽  
pp. 2129-2145
Author(s):  
Sayori Kiyota ◽  
Masafumi Hirano
Keyword(s):  
Conjugated Dienes ◽  
Induction Effect ◽  
Internal Alkynes ◽  
Conjugated Trienes ◽  
Insight Into

Ru(0)-Catalysed cross-dimerisation of unsymmetrical internal alkynes with conjugated dienes yields two conjugated trienes depending on the regioselectivity. The regioselectivity is dominantly controlled by the induction effect of the substituents.

Ru(0)-Catalyzed Direct Coupling of Internal Alkynes with Conjugated Dienes: An Efficient Access to Conjugated Trienes

2016 ◽  
Vol 35 (24) ◽  
pp. 4033-4043 ◽  
Author(s):  
Sayori Kiyota ◽  
Seonyong In ◽  
Ryo Saito ◽  
Nobuyuki Komine ◽  
Masafumi Hirano
Keyword(s):  
Conjugated Dienes ◽  
Direct Coupling ◽  
Efficient Access ◽  
Internal Alkynes ◽  
Conjugated Trienes

Steric Effects in Reactions of Decamethyltitanocene Hydride with Internal Alkynes, Conjugated Diynes, and Conjugated Dienes

2014 ◽  
Vol 33 (13) ◽  
pp. 3399-3413 ◽  
Author(s):  
Jiří Pinkas ◽  
Róbert Gyepes ◽  
Ivana Císařová ◽  
Jiří Kubišta ◽  
Michal Horáček ◽  
...  
Keyword(s):  
Conjugated Dienes ◽  
Steric Effects ◽  
Internal Alkynes ◽  
Conjugated Diynes

High-Molecular-Weight, High-Unsaturation Copolymers of Isobutylene and Conjugated Dienes. I. Synthesis

1976 ◽  
Vol 49 (4) ◽  
pp. 960-966 ◽  
Author(s):  
W. A. Thaler ◽  
D. J. Buckley
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Cationic Polymerization ◽  
Critical Role ◽  
Conjugated Dienes ◽  
Solution Properties ◽  
Insight Into

Abstract This investigation has provided insight into the critical role of solution properties on the course of cationic polymerization and has led to a technique for reconciling the opposing demands for synthesis of isoolefin-diene copolymers both free from gel and high in molecular weight. By this technique, the synthesis of a broad range of intermediate-unsaturation elastomers of quality has been realized.

scholarly journals Effects of microwave and conventional heating on the oxidative stability of corn oil enriched with different antioxidants

2019 ◽  
Vol 70 (4) ◽  
pp. 326
Author(s):  
A. Baştürk
Keyword(s):  
Antioxidant Activity ◽  
Fatty Acid ◽  
Reaction Rate ◽  
Corn Oil ◽  
Ascorbyl Palmitate ◽  
Conjugated Dienes ◽  
Conventional Heating ◽  
Rosemary Extract ◽  
Conjugated Trienes ◽  
Severe Deterioration

Four different corn oil samples including stripped (SCO, Control), refined (RCO), stripped corn oil enriched with rosemary extract (SCO+ROS) and ascorbyl palmitate (SCO+AP) were exposed to microwave (MWH) and conventional heating (CVH). For both heating methods, peroxide value (PV) and conjugated dienes increased at up to 230 °C, at which temperature hexanal (HEX) and conjugated trienes started to increase instead. Kinetic analysis revealed that PV and HEX formation were first ordered and the reaction rate among the samples was as follows: Control > SCO+ROS > RCO > SCO + AP for PV and SCO + ROS > RCO > SCO+AP > Control for HEX. The unsaturated fatty acid contents of CVH and MWH treated samples showed 9.5 and 12.9% reduction in SCO, while they were 2.9 and 7.7% in RCO, 3.6 and 6.1% in SCO + ROS, and finally 4.0 and 4.8% in SCO + AP. It was concluded that MWH led to a more severe deterioration and that the antioxidant activity of ROS was superior to that of AP for both heating methods.

Effect of Berries Extracts on the Oxidative Stability of Silybum marianum Oil and its 20% Oil-in-water Emulsion

2008 ◽  
Vol 59 (9) ◽  
Author(s):  
Mariana Pop ◽  
Alfa Xenia Lupea
Keyword(s):  
Oxidation Process ◽  
Conjugated Dienes ◽  
Silybum Marianum ◽  
Water Emulsion ◽  
Ambient Storage ◽  
Oil In Water ◽  
Conjugated Trienes ◽  
The Stability ◽  
Oil In Water Emulsion ◽  
Mountain Cranberry

The effect of Vaccinium vitis-idaea (mountain cranberry) and Vaccinium myrtilus (bilberry) fruits extracts on the stability of Silybum marianum oil and its 20% oil-in-water emulsion under ambient storage were investigated. The oxidation process of oil and emulsions was followed by measuring the peroxide value (PV), conjugated dienes (CD), conjugated trienes (CT) and p-anisidine value (p-AV).

scholarly journals Oxidation of Olive Oils during Microwave and Conventional Heating for Fast Food Preparation

2009 ◽  
Vol 27 (Special Issue 1) ◽  
pp. S173-S177 ◽  
Author(s):  
E. Abd El-Moneim Mahmoud ◽  
J. Dostálová ◽  
J. Pokorný ◽  
D. Lukešová ◽  
M. Doležal
Keyword(s):  
Fast Food ◽  
Oxidation Stability ◽  
Microwave Treatment ◽  
Conjugated Dienes ◽  
Microwave Oven ◽  
Oxidation Products ◽  
Conventional Heating ◽  
Olive Oils ◽  
Peroxide Values ◽  
Conjugated Trienes

The oxidation stability of extra virgin and refined olive oils produced in different countries were studied under different conditions of microwave heating (microwave oven Electrolux, 2450 MHz, 500 W) and conventional heating (200°C). Oils were heated in a microwave oven and in a conventional oven for 0, 3, 6, 9, 12, 15, 20, 25, and 30 minutes. The evaluated parameters were peroxide value, content of conjugated dienes, conjugated trienes (determined by absorbance at 233 nm and 274 nm, respectively), and fatty acid composition by GC. During microwave and conventional heating peroxide values and contents of dienoic compounds differed significantly between control and the heated samples. The microwave treatment did not produce significantly greater amount of oxidation products than traditional heating.

CpTiCl 2 ‐Catalyzed Cross‐Coupling between Internal Alkynes and Ketones: A Novel Concept in the Synthesis of Halogenated, Conjugated Dienes

2020 ◽  
Vol 26 (37) ◽  
pp. 8296-8301
Author(s):  
Esther Roldan‐Molina ◽  
Maria M. Nievas ◽  
Jorge A. R. Navarro ◽  
J. Enrique Oltra
Keyword(s):  
Cross Coupling ◽  
Conjugated Dienes ◽  
Internal Alkynes ◽  
Novel Concept

scholarly journals Oxidative stabilization of corn oil with spinach extract

2019 ◽  
Vol 54 (4) ◽  
pp. 375-382
Author(s):  
M Tehseen ◽  
S Hina ◽  
Alim Un Nisa ◽  
A Ahmad
Keyword(s):  
Antioxidant Activity ◽  
Fatty Acid ◽  
Corn Oil ◽  
Spinacia Oleracea ◽  
Conjugated Dienes ◽  
Synthetic Antioxidants ◽  
Oxidative Stabilization ◽  
Anisidine Value ◽  
Spinach Extract ◽  
Conjugated Trienes

The present study was aimed to analyze the antioxidant activity of spinach (Spinacia oleracea) extract in oxidative stabilization of refined, bleached and de-odorized (RBD) corn oil (CO). Corn oil was supplemented with three different concentrations 600, 1200 and 1800 ppm of methanolic spinach extract and then stored at 25oC and 60oC. Different oxidation measuring parameters such as peroxide value (PV), free fatty acid (FFA) value, iodine value (IV), conjugated dienes (CD), conjugated trienes (CT) and para-anisidine value (PAV) were examined. The potency of spinach extract as natural antioxidant was found to be as effective as the synthetic antioxidants BHA and BHT used as standards and highest stabilization was observed in the order CO-1800>CO-1200>CO-BHT> CO-BHA>CO-600>CO-control. The results showed a significant effect of spinach extract in enhancing the oxidative stability of corn oil. Bangladesh J. Sci. Ind. Res.54(4), 375-382, 2019

scholarly journals Oxidative Stability of Soybean Oil Supplemented with Pod Coat Extracts of Cluster Bean

2019 ◽  
pp. 1-11
Author(s):  
Sukriti Nehra ◽  
Sushila Singh
Keyword(s):  
Soybean Oil ◽  
Oxidative Stability ◽  
Oxidative Degradation ◽  
Quality Parameters ◽  
Conjugated Dienes ◽  
Acetone Extract ◽  
Cluster Bean ◽  
Crude Soybean Oil ◽  
Conjugated Trienes ◽  
Totox Value

The aim of present work was to determine the potency of phenolic extracts from cluster bean pod coats in improving shelf life of soybean oil. Pod coats of cluster bean were extracted with three solvents (acetone, ethylacetate and chloroform). Crude soybean oil samples were stabilised by adding different extracts at 1000 and 2000 ppm concentration and effect of addition of these extracts on oxidative stability of crude soybean oil at 50°C was observed. Rate of oxidative degradation of crude soybean oil was lowest in the sample treated with acetone extract (2000 ppm). The value of various oxidative quality parameters of crude soybean oil supplemented with acetone extract (2000 ppm) after 28 days of incubation are peroxide value (26.77 meq/kg oil), free fatty acids content (2.637%), p-anisidine value (25.18), TOTOX value (78.72), conjugated dienes (28.47%), conjugated trienes (13.97%) and TBA value (31.59 meq malonaldehyde/g). Results of present study indicate that pod coat extracts of cluster bean possess remarkable antioxidant potential and considerably lowered the rate of oxidative deterioration of crude soybean oil.

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