Substitution at saturated carbon. Part 22. Rate constants for the substitution of tetraethyltin by mercury(II) carboxylates in t-butyl alcohol, acetonitrile, acetone, and ethyl acetate

1977 ◽  
pp. 1225 ◽  
Author(s):  
Michael H. Abraham ◽  
Davood Farshbaf Dadjour ◽  
Mohammad Reza Sedaghat-Herati
Keyword(s):  
Ethyl Acetate ◽  
Rate Constants ◽  
Butyl Alcohol

HSCCC Separation of Three Main Compounds from the Crude Extract of Dracocephalum Tanguticum by Using Dimethyl Sulfoxide as Cosolvent

2020 ◽  
Author(s):  
Xue Yang ◽  
Yongling Liu ◽  
Tao Chen ◽  
Nana Wang ◽  
Hongmei Li ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Ethyl Acetate ◽  
Dimethyl Sulfoxide ◽  
Efficient Method ◽  
Crude Extract ◽  
High Speed ◽  
Glacial Acetic Acid ◽  
Butyl Alcohol ◽  
Preparative Hplc ◽  
Counter Current

Abstract Separation of natural compounds directly from the crude extract is a challenging work for traditional column chromatography. In the present study, an efficient method for separation of three main compounds from the crude extract of Dracocephalum tanguticum has been successfully established by high-speed counter-current chromatography (HSCCC). The crude extract was directly introduced into HSCCC by using dimethyl sulfoxide as cosolvent. Ethyl acetate/n-butyl alcohol/0.3% glacial acetic acid (4: 1: 5, v/v) system was used and three target compounds with purity higher than 80% were obtained. Preparative HPLC was used for further purification and three target compounds with purity higher than 98% were obtained. The compounds were identified as chlorogenic acid, pedaliin and pedaliin-6″-acetate.

The reactivity of allyl and propargyl alcohols with solvated electrons: temperature and solvent effects

1979 ◽  
Vol 57 (8) ◽  
pp. 839-845 ◽  
Author(s):  
Alexei M. Afanassiev ◽  
Kiyoshi Okazaki ◽  
Gordon R. Freeman
Keyword(s):  
Activation Energy ◽  
Ethylene Glycol ◽  
Rate Constants ◽  
Allyl Alcohol ◽  
Trap Depth ◽  
Activation Energies ◽  
Butyl Alcohol ◽  
Solvated Electrons ◽  
Tert Butyl ◽  
Tert Butyl Alcohol

The rate constants k1 for the reaction of solvated electrons with allyl alcohol in a number of hydroxylic solvents differ by up to two orders of magnitude and decrease in the order tert-butyl alcohol > 2-propanol > 1-propanol ≈ ethanol > methanol ≈ ethylene glycol > water. In methanol and ethylene glycol the rate constants (7 × 107 M−1 s−1 at 298 K) and activation energies (16 kJ/mol) are equal, in spite of a 32-fold difference in solvent viscosity (0.54 and 17.3 cP, respectively) and 3-fold difference in its activation energy (11 and 32 kJ/mol, respectively). The reaction in tert-butyl alcohol is nearly diffusion controlled and has a high activation energy that is characteristic of transport in that liquid (E1 = 31 kJ/mol, Eη = 39 kJ/mol). The activation energies in the other alcohols are all 16 kJ/mol, and it is 14 kJ/mol in water. They do not correlate with transport properties. The solvent effect is connected primarily with the entropy of activation. The rate constants correlate with the solvated electron trap depth. When the electron affinity of the scavenger is small, a favorable configuration of solvent molecules about the electron/scavenger encounter pair is required for the electron jump to take place. The behavior of the rate parameters for propargyl alcohol is similar to that for allyl alcohol, but k1, A1, and E1 are larger for the former. The ratio k(propargyl)/k(allyl) at 298 K equals 10.5 in water and decreases through the series, reaching 1.3 in tert-butyl alcohol. Rate parameters for several other scavengers are also reported.

Comparison on Antimicrobial Activity of Different Solvent Extracts from Aerial Stem and Rhizome of Douttuynia cordata

2013 ◽  
Vol 706-708 ◽  
pp. 44-47
Author(s):  
Shao Juan Jiang
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Bacillus Subtilis ◽  
Aspergillus Niger ◽  
Ethyl Acetate ◽  
Water Extract ◽  
Butyl Alcohol ◽  
Alcohol Extract ◽  
Houttuynia Cordata ◽  
Aerial Stem

The 95% of ethanol crude extract of aerial stem and rhizome of houttuynia cordata was sequentially extracted with petroleum ether, ethyl acetate, n-butyl alcohol and water. Antimicrobial activity and minimum inhibitory concentration (MIC) of the different extracts against Staphylococlus aureus, Escherichia coli, Bacillus subtilis, Aspergillus niger and Saccharomycetes were examined with filter paper method. And antimicrobial activity between aerial stem and rhizome was compared. The result showed that, among the extracts of aerial stem and rhizome of houttuynia cordata, with regard to antimicrobial activity, water extract was strongest against Staphylococlus aureus, and ethyl acetate extract was strongest against Escherichia coli, and n-butyl alcohol extract was strongest against Bacillus subtilis and Saccharomycetes, while each extract had no significant antimicrobial activity against Aspergillus niger. Moreover, the antimicrobial activity of rhizome was stronger than that of the aerial stem.

On the Rate of the Acid-Catalyzedtrans-Esterification of Butyl Alcohol and Ethyl Acetate

1949 ◽  
Vol 71 (6) ◽  
pp. 1991-1994 ◽  
Author(s):  
L. Farkas ◽  
O. Schachter ◽  
B. H. Vromen
Keyword(s):  
Ethyl Acetate ◽  
Butyl Alcohol

Synthesis and thermolysis rate constants of diastereomeric oxadiazoline sources of acetoxy(methoxy)carbene — Reaction of acetoxy(methoxy)carbene with isocyanates

2006 ◽  
Vol 84 (7) ◽  
pp. 927-933 ◽  
Author(s):  
Wojciech Sokol ◽  
John Warkentin
Keyword(s):  
Acetic Acid ◽  
Ethyl Acetate ◽  
Carbonyl Group ◽  
Rate Constants ◽  
Acid Catalysis ◽  
Major Product ◽  
Acetyl Group ◽  
Methyl Pyruvate ◽  
Acetyl Transfer ◽  
Cis And Trans

Oxidation of the methoxycarbonylhydrazone of p-methoxyacetophenone affords both the cis- and trans-2-acetoxy-2-methoxy-5-(p-methoxyphenyl)-5-methyl-Δ3-1,3,4-oxadiazolines (also known as corresponding 2,5-dihydro-1,3,4-oxadiazoles) as well as methyl 1-acetoxy-1-(p-methoxyphenylethyl)diazenecarboxylate. The three isomers were separated and identified by spectroscopic means. Methyl 1-acetoxy-1-(p-methoxyphenylethyl)diazenecarboxylate is the major product from oxidation in dichloromethane. Oxidation in acetic acid did not afford the oxadiazolines but gave the diazenecarboxylate and, in addition, 1-(p-methoxyphenyl)ethyl acetate. Attempts to isomerize the diazenecar boxylate to the oxadiazolines by acid catalysis were not successful. Thermolysis of the oxadiazolines at 50.4 °C occurred with approximately the same rate constant (ca. 3.6 × 10–5 s–1) to afford acetoxy(methoxy)carbene, which rearranges to methyl pyruvate by acetyl transfer. The carbene, which reacts with relatively unhindered isocyanates to transfer the methoxy carbonyl group to carbon and the acetyl group to nitrogen, can be considered an acyl anion equivalent in that reaction.Key words: acetoxy(methoxy)carbene, diazene, oxadiazoline, isocyanate, (acetylamino)oxoacetate.

The transmission of polar effects. Part X. The esterification with diazodiphenyl-methane and the ionization of 9-substituted 10-anthroic and 8-substituted 1-naphthoic acids

1969 ◽  
Vol 47 (2) ◽  
pp. 185-190 ◽  
Author(s):  
Keith Bowden ◽  
D. C. Parkin
Keyword(s):  
Free Energy ◽  
Ethyl Acetate ◽  
Field Effect ◽  
Isopropyl Alcohol ◽  
Substituent Effects ◽  
Butyl Alcohol ◽  
Rate Coefficients ◽  
Linear Free Energy ◽  
Energy Relations ◽  
Substituted 1

The rate coefficients for the reaction with diazodiphenylmethane in methanol, ethanol, isopropyl alcohol, t-butyl alcohol, 2-methoxyethanol, 2-n-butoxyethanol, and ethyl acetate at 30° and the pKa values in 80% 2-n-butoxyethanol–water of a series of 9-substituted 10-anthroic and 8-substituted 1-naphthoic acids have been determined. The effect of substitution has been analyzed by linear free energy relations. The variation in the susceptibilities of the systems to polar substituent effects with the medium are examined. The occurrence of reversed dipolar substituent effects in the reactions of the 1,8-naphthoic acids is detected. The implications of the results for the inductive and field effect models for the transmission of polar effects are discussed.

The Antibacterial Activity of the Extracts of Apocynum Venetum and Apocynum Venetum Fiber

2011 ◽  
Vol 233-235 ◽  
pp. 2328-2331 ◽  
Author(s):  
Hui Juan Wang ◽  
Hao Chen ◽  
Guang Ting Han
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Bacillus Subtilis ◽  
Candida Albicans ◽  
Ethyl Acetate ◽  
Antibacterial Effect ◽  
Antibacterial Activities ◽  
Butyl Alcohol ◽  
Apocynum Venetum

In this study, the total flavone contents of Apocynum venetum extract and Apocynum venetum fiber extracts were evaluated. Their antibacterial activity was tested via testing the antibacterial effect of their aqueous, ethyl acetate and n-butyl alcohol extracts. The results were showed that both the materials extracts at the concentration of 100, 50mg/ml had significantly antibacterial activities against staphylococcus aureus, and had a few effect on bacillus subtilis, pseudomonadaceae, pseudomonas aeruginosa, staphylococcus epidermidis, escherichia coli and candida albicans.

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