Perchloric acid catalyzed acylation of anisole

1976 ◽  
Vol 10 (3) ◽  
pp. 363-364
Author(s):  
B. M. Savin ◽  
S. A. Kesler
Keyword(s):  
Perchloric Acid ◽  
Acid Catalyzed

The acid-catalyzed demetalation of 1-(tri-n-butylstannyl)-2-phenylethyne. A surprisingly small β-stannyl effect

1996 ◽  
Vol 74 (7) ◽  
pp. 1366-1368 ◽  
Author(s):  
I. Egle ◽  
V. Gabelica ◽  
A.J. Kresge ◽  
T.T. Tidwell
Keyword(s):  
Key Words ◽  
Isotope Effect ◽  
Acid Concentration ◽  
Rate Constant ◽  
Perchloric Acid ◽  
Hydronium Ion ◽  
Stabilizing Effect ◽  
Aromatic Product ◽  
Acid Catalyzed ◽  
The Difference

Rates of conversion of 1-(tri-n-butylstannyl)-2-phenylethyne to phenylethyne in H2O and D2O solutions of perchloric acid were found to be proportional to acid concentration, giving the hydronium ion rate constant [Formula: see text] and the isotope effect [Formula: see text]. The magnitude of this isotope effect suggests that the reaction occurs by rate-determining hydron transfer to the substrate, producing a vinyl carbocation; this carbocation then loses its tributylstannyl group, giving phenylacetylene as the only detectable aromatic product. The hydronium ion rate constant, when compared to the rates of protonation of phenylethyne and 1-(trimethylsilyl)-2-phenylethyne, gives a β-stannyl stabilizing effect of δΔG≠ = 6.6 kcal mol−1 and a differential β-stannyl/β-silyl effect of δΔG≠ = 3.2 kcal mol−1. These stabilizations are very much smaller than previously reported β-stannyl effects. Possible reasons for the difference are suggested. Key words: β-stannyl effect, β-silyl effect, carbocation stabilization, protodemetalation.

ChemInform Abstract: Silica Supported Perchloric Acid Catalyzed Rapid N-Formylation under Solvent-Free Conditions.

ChemInform ◽  
2012 ◽  
Vol 43 (32) ◽  
pp. no-no
Author(s):  
Mohd. Imran Ansari ◽  
Mohd. Kamil Hussain ◽  
Nisha Yadav ◽  
Puneet K. Gupta ◽  
K. Hajela
Keyword(s):  
Perchloric Acid ◽  
Solvent Free ◽  
Solvent Free Conditions ◽  
Acid Catalyzed

Oxidation of 1,4-dimethylcyclohexane by perchloric acid catalyzed by polyphenylferrosiloxane

1998 ◽  
Vol 47 (3) ◽  
pp. 435-437 ◽  
Author(s):  
V. S. Kulikova ◽  
M. M. Levitsky ◽  
A. F. Shestakov ◽  
A. E. Shilov
Keyword(s):  
Perchloric Acid ◽  
Acid Catalyzed

Determination of Mercaptosilanes by Perchloric Acid-Catalyzed Acetylation and with Mercuric Acetate.

1964 ◽  
Vol 36 (6) ◽  
pp. 1156-1157 ◽  
Author(s):  
Abe. Berger ◽  
J. A. Magnuson
Keyword(s):  
Perchloric Acid ◽  
Mercuric Acetate ◽  
Acid Catalyzed

EFFECT OF PRESSURE AND TEMPERATURE ON THE RATE OF THE ACID-CATALYZED HYDRATION OF ETHYLENE

1965 ◽  
Vol 43 (9) ◽  
pp. 2453-2456 ◽  
Author(s):  
B. T. Baliga ◽  
E. Whalley
Keyword(s):  
Transition State ◽  
Perchloric Acid ◽  
Kcal Mole ◽  
Effect Of Pressure ◽  
Energy Entropy ◽  
Acid Catalyzed ◽  
Aqueous Perchloric Acid

The rate of hydration of ethylene in dilute aqueous perchloric acid has been measured in the range 170–190 °C at 100 bars and 100 to 3 000 bars at 180 °C. The energy, entropy, and volume of activation are 33.3 ± ~1 kcal mole−1, −5.7 ± ~2.5 cal deg−1 mole−1, and − 15.5 ± ~1.5 cm3 mole−1 respectively. The volume of activation shows that at least one molecule of water is strongly bound in the transition state.

scholarly journals Acid-Catalyzed Hydrolysis of Some Secondary Alkyl Phenyl Ethers in Perchloric Acid: Kinetics and Mechanism.

1992 ◽  
Vol 46 ◽  
pp. 726-731 ◽  
Author(s):  
Martti Lajunen ◽  
Mika Kähkönen ◽  
Yngve Stenstrøm ◽  
Adolf Gogoll ◽  
Kjell Undheim ◽  
...  
Keyword(s):  
Perchloric Acid ◽  
Kinetics And Mechanism ◽  
Acid Catalyzed ◽  
Phenyl Ethers ◽  
Hydrolysis Of

ChemInform Abstract: Silica-Supported Perchloric Acid Catalyzed One-Pot Synthesis of 1,4-Dihydropyridines.

ChemInform ◽  
2012 ◽  
Vol 43 (12) ◽  
pp. no-no
Author(s):  
Dasari Ramesh ◽  
Singanaboina Rajaram ◽  
Manchala Narasimhulu ◽  
Thummalpally Srikanth Reddy ◽  
Kondempudi Chinni Mahesh ◽  
...  
Keyword(s):  
Perchloric Acid ◽  
One Pot ◽  
One Pot Synthesis ◽  
Acid Catalyzed

The hydration of mesitylketene in aqueous solution: detection of acid catalysis for an aromatic ketene

1995 ◽  
Vol 73 (4) ◽  
pp. 539-543 ◽  
Author(s):  
J. Andraos ◽  
A.J. Kresge ◽  
N.P. Schepp
Keyword(s):  
Aqueous Solution ◽  
Carbon Atom ◽  
Perchloric Acid ◽  
Reaction Rate ◽  
Acid Catalysis ◽  
Sodium Perchlorate ◽  
Nucleophilic Attack ◽  
Acid Solutions ◽  
Uncatalyzed Reaction ◽  
Acid Catalyzed

Mesitylketene was generated flash photolytically in aqueous solution by the photo-Wolff reaction of 2,4,6-trimethyldiazoacetophenone and also by rearrangement of mesitylynol obtained through photodecarbonylation of mesitylhydroxycyclopropenone, and rates of hydration of this ketene were measured in dilute perchloric acid, sodium perchlorate, and sodium hydroxide solutions as well as in concentrated sodium perchlorate and perchloric acid solutions. In dilute solution only an uncatalyzed reaction and a sodium-hydroxide-catalyzed process were observed, both of which could be attributed to nucleophilic attack, by water and by hydroxide ion, respectively, at the ketene carbonyl carbon atom. In concentrated sodium perchlorate solutions, a mild decrease in reaction rate with increasing salt concentration was observed, as expected on the basis of decreasing water activity and a consequent slowing of the uncatalyzed reaction. A similar mild decrease was found in perchloric acid solutions up to [Formula: see text] but this then gave way to a rate increase that became dominant above [Formula: see text] This appearance of acid catalysis indicates a change in reaction mechanism from nucleophilic attack of water to an electrophilic process involving rate-determining protonation on the β-carbon atom of the ketene group. Analysis of the acid-catalyzed reaction rate by the Cox–Yates method gives the catalytic coefficient [Formula: see text] This, when compared with [Formula: see text] for ketene itself, shows that the mesityl group retards acid-catalyzed hydration by a factor of 2200, and consequently the acid-catalyzed reaction of this, and other aromatic ketenes as well, becomes apparent only under strongly acidic conditions. Keywords: mesitylketene, ketene hydration, acid catalysis, Cox–Yates excess acidity correlation.

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