157. Acylation reactions catalysed by strong acids. Part V. Mixtures of zinc chloride and acetyl chloride or acetic anhydride as sources of acetylium ions

1951 ◽  
pp. 726 ◽  
Author(s):  
H. Burton ◽  
P. F. G. Praill
Keyword(s):  
Acetic Anhydride ◽  
Zinc Chloride ◽  
Acetyl Chloride ◽  
Strong Acids ◽  
Acylation Reactions

Color Reactions of Rubber and Gutta-Percha

1929 ◽  
Vol 2 (2) ◽  
pp. 193-196
Author(s):  
F. Kirchhof
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Zinc Chloride ◽  
Trichloroacetic Acid ◽  
Acetyl Chloride ◽  
Oxidation Products ◽  
Arsenic Trichloride ◽  
Gutta Percha ◽  
Long Time ◽  
Color Reactions

Abstract THE present paper was suggested by a recent publication of Pauly on the same subject, who applied the well known sterol reactions of Hesse, Liebermann, Tschugajeff, etc., to the hydrocarbons of rubber and gutta-percha. These reactions depend either upon the action of concentrated H2SO4 on chloroform solutions of the substances in the presence or absence of acetic anhydride (Liebermann, Burchard and Hesse reactions) or other solvents, or condensation reagents are used, such as acetyl chloride and zinc chloride by Tschugajeff, and acetic acid with arsenic trichloride by Kahlenberg, and trichloroacetic acid with a trace of formaldehyde by Godoletz. All the known sterol reactions take place also with rubber or gutta-percha, with the appearance of intense red or violet colorations of varying stability, the color depending in part upon the quality and in part upon the purity of the samples. The Burchard reaction in particular is very sensitive in these respects. Thus with rubber purified with alkali by the Pummerer method, the color is a Bordeaux red which does not change for a long time, whereas solutions of unpurified rubber change rapidly, a change which is rightly ascribed by Pauly to relatively rapid oxidation in the presence of oxidation products in the case of the unpurified rubber.

CATALYZED NITRATION OF AMINES: VIII. THE MEDIUM USED IN NITRATION OF SECONDARY ALIPHATIC AMINES

1948 ◽  
Vol 26b (3) ◽  
pp. 294-308 ◽  
Author(s):  
Thelma Connor ◽  
George F Wright ◽  
G. N. R. Smart
Keyword(s):  
Nitric Acid ◽  
Acetic Anhydride ◽  
Hydrogen Chloride ◽  
Zinc Chloride ◽  
Acetyl Chloride ◽  
Maximum Amount ◽  
Initial Formation ◽  
Reaction Systems ◽  
Elemental Chlorine ◽  
Rate Controlling Step

The reaction [Formula: see text] has been found to be reversible in acetic anhydride. Analysis for electropositive chlorine and for nitric acid in this reacting system indicates that consumption of NO3− and production of Cl+ passes through a maximum after which nitric acid is regenerated and electropositive chlorine disappears. This phenomenon has been interpreted as an initial formation of chlorine acetate (or other chlorine ester) which then decomposes to give elemental chlorine. The increased demand for hydrogen chloride then shifts the equilibrium toward regeneration of nitric acid. The reaction has been found to be second order in its kinetics, with an activation energy of about 8000 cal. It is probably not the rate-controlling step in the catalyzed nitration, except perhaps where such nitration is easy and efficient. When nitration is difficult the electropositive chlorine tends to accumulate. When it becomes elemental chlorine, it is ineffective for nitration catalysis and is destructive to the amine. The catalysts acetyl chloride and zinc chloride have been studied. Electropositive chlorine formation occurs at the same rate with acetyl chloride as with hydrogen chloride. Zinc chloride, on the other hand, has been found to generate the maximum amount of electropositive chlorine immediately. This indicates that zinc chloride would be a good catalyst for easily nitrated amines but less efficient for amines which react more slowly, since the chlorine acetate not consumed by chloramination would decompose to give the destructive elemental chlorine. No mono-, di-, or trichloroacetic acids, nor perchloric acid, could be detected in aged reaction systems initially hydrogen chloride – nitric acid – acetic anhydride.

scholarly journals THE ESTIMATION OF SOME 17-ALKYL-SUBSTITUTED STEROIDS WITH THE ZINC CHLORIDE – ACETYL CHLORIDE (TSHUGAEV) REAGENT AND A POSTULATED REACTION MECHANISM

1951 ◽  
Vol 29 (2) ◽  
pp. 217-222 ◽  
Author(s):  
R. H. Cox ◽  
E. Y. Spencer
Keyword(s):  
Reaction Mechanism ◽  
Acetic Anhydride ◽  
Sulphuric Acid ◽  
Zinc Chloride ◽  
Acetyl Chloride ◽  
Maximum Absorption ◽  
Ring Cleavage ◽  
Reaction Products ◽  
Experimental Support

The reactivity of a number of 17-alkyl-substituted steroids toward the zinc chloride – acetyl chloride (Tshugaev) reagent has been investigated. Maximum absorption values of reaction products were determined spectrophotometrically. A general parallelism between the Liebermann–Burchard (sulphuric acid-acetic anhydride) and the Tshugaev reagent was confirmed except in the case of 5: 6 unsaturated 7-ketosteroids, which reacted to the latter reagent only. Arguments against currently suggested mechanisms for the Liebermann–Burchard reaction are presented, and a new mechanism for color production is postulated which involves ring cleavage. Experimental support is offered.

scholarly journals Catalytic oxidation of toluene by ozone in the system "acetic anhydride–strong acid"

2021 ◽  
pp. 106-111
Author(s):  
E.V. Potapenko ◽  
◽  
P.Y. Andreev ◽  
I.P. Isayenko ◽  
N.S. Andreeva
Keyword(s):  
Transition Metals ◽  
Acetic Anhydride ◽  
Kinetic Parameters ◽  
Catalytic Oxidation ◽  
Decisive Role ◽  
Strong Acid ◽  
Oxidation Products ◽  
Substrate Conversion ◽  
High Degree ◽  
Strong Acids

The process of catalytic oxidation of toluene by ozone in the solution of a mixture "acetic anhydride–a strong acid" has been studied in the presence of compounds of transition metals. It is shown that the main oxidation products in the system Mn(Ac)2–(СН3СО)2О–Н2SO4 at 200C are benzylacetate and benzylidene diacetate with the yields of 39% and 29%, respectively. In the system Со(Ac)2–(СН3СО)2О–НА, the reaction is accompanied mainly by the formation of benzylidene diacetate (68.0%) and the yield of benzylacetate does not exceed 4.0%. The kinetic parameters of the main stages of the catalytic cycle were investigated. It was found that strong acids play a decisive role in increasing the activity of oxidized forms of the metal. Under the conditions of activation by strong acids, the reaction of methylbenzene with Me3+ occurs with a high degree of substrate conversion. It was found that the reduction of Me3+ in the reaction with the solvent becomes noticeable, along with the oxidation of toluene, with increasing the concentration of strong acids. It was stated that the selective oxidation of toluene under catalysis is initiated by the reaction with an oxidized form of the metal formed by the interaction of ozone with the catalyst.

Acetylation and Formylation of 3-Ferrocenylpyrroles

1999 ◽  
Vol 64 (1) ◽  
pp. 99-106
Author(s):  
Battsengel Gotov ◽  
Štefan Toma ◽  
Eva Solčániová
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Aluminum Chloride ◽  
Acetyl Chloride ◽  
Trifluoroacetic Anhydride ◽  
Acid Mixture ◽  
Chloride Method

Acetylations of 3-ferrocenyl-1-methylpyrrole as well as 3-cyano-4-ferrocenylpyrrole and 3-cyano-4-ferrocenyl-1-methylpyrrole were performed. The course of the acylation is highly dependent on the acylation agent, that is acetyl chloride/aluminum chloride (method A), trifluoroacetic anhydride-acetic acid mixture (method B) or acetic anhydride/Sc(OTf)3 (method C). Method A gives the acetylation on ferrocene moiety, method B affords the trifluoroacetylation on pyrrole moiety and method C affords pyrrole moiety acetylation. Vielsmeier-Haack formylation gives the products of substitution on pyrrole moiety.

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