The Course of Autoöxidation Reactions in Polyisoprene and Allied Compounds. III. The Oxidation of Rubber in the Presence of Acetic Acid or Acetic Anhydride

1944 ◽  
Vol 17 (2) ◽  
pp. 267-276
Author(s):  
George F. Bloomfield
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Chain Scission ◽  
Considerable Proportion ◽  
Hydroxyl Groups ◽  
Carbonyl Groups ◽  
Free Hydroxyl ◽  
Hydrolysis Of ◽  
Oxygenated Products ◽  
Oxidative Attack

Abstract Oxidation of rubber by oxygen in the presence of acetic anhydride leads to formation of highly oxygenated products containing a considerable proportion of acetoxyl groups. The residual unsaturation of the products of highest acetoxyl content, taken in conjunction with other analytical characteristics, indicates that three, rather than two, acetoxyl groups normally combine with each isoprene unit attacked. Although the bulk of the oxygen introduced is present in the form of acetoxyl groups, a portion occurs as carboxyl and carbonyl groups; also, whenever acetic acid is used (partly or wholly) in place of acetic anhydride, some free hydroxyl groups appear in the oxidized rubber. The proportions of carboxyl and carbonyl groups observed can be correlated satisfactorily with the extent of chain-scission occurring during the oxidation, the groups in question forming the new ends of the severed molecules. Hydrolysis of the acetylated products yields hydroxy acids, which readily undergo lactonic elimination of water. Acetic anhydride and acetic acid can clearly act as auxiliary reagents in autoöxidation reactions, and the detailed results obtained with rubber can be best accounted for on the basis of α-methylene peroxidation, followed by decay reactions involving incorporation of the auxiliary reagent as well as oxidative attack at the double bonds of the rubber.

NMR study of the synthesis of17O-enriched acetic acid by hydrolysis of acetic anhydride with17O-enriched water

2003 ◽  
Vol 41 (11) ◽  
pp. 959-961 ◽  
Author(s):  
Heidi M. Hultman ◽  
Kristina Djanashvili ◽  
Joop A. Peters
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Nmr Study ◽  
Hydrolysis Of

Synthetic application of cyclobutanes V. α-Carbalkoxymethylation of α, β-unsaturated ketones

1977 ◽  
Vol 55 (5) ◽  
pp. 822-830 ◽  
Author(s):  
Hsing-Jang Liu ◽  
Patrick Chi-Lin Yao
Keyword(s):  
Hydrogen Peroxide ◽  
Acetic Acid ◽  
Acetic Anhydride ◽  
Potassium Carbonate ◽  
Alkyl Iodide ◽  
Keto Ester ◽  
Unsaturated Ketones ◽  
Synthetic Application ◽  
Hydrolysis Of ◽  
Villiger Oxidation

Two general methods for α-carbalkoxymethylation of both enolizable and nonenolizable (towards the γ-position) α,β-unsaturated ketones have been developed. Method A involves three synthetic steps: photocycloaddition of the starting enone to 1,1-dimethoxyethylene, hydrolysis–oxidation of the adduct with acetic acid and 30% hydrogen peroxide, and O-alkylation of the resulting mixture of lactone and acid using anhydrous potassium carbonate and an alkyl iodide, e.g., 13 → 17 → 21 + 22 → 23. Method B differs from method A in the means of securing the required cyclobutanone intermediate. Thus, photocycloaddition of 13 to vinyl acetate followed by hydrolysis of the adduct gave two epimeric keto alcohols 39 whose oxidation with dimethyl sulfoxide and acetic anhydride afforded diketone 40. Baeyer–Villiger oxidation of 40 followed by methylation of the products 21 and 22 completed the overall α-carbomethoxymethylation process to give keto ester 23.

Fluorine-containing Heterocycles: Part II Synthesis and Reactions of New Thieno[2,3-b]Pyridine Derivatives Bearing Trifluoromethyl Group

2005 ◽  
Vol 2005 (7) ◽  
pp. 461-468 ◽  
Author(s):  
Abdu E. Abdel-Rahman ◽  
Etify A. Bakhite ◽  
Elham A. Al-Taifi
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Formic Acid ◽  
Triethyl Orthoformate ◽  
Trifluoromethyl Group ◽  
Pyridine Derivatives ◽  
Unexpected Product ◽  
Acyl Azide ◽  
Hydrolysis Of ◽  
Heterocyclic Aldehydes

Ethyl [3-cyano-6-(2-thienyl)-4-trifluoromethylpyridin-2-ylthio]acetate (2) and ethyl 3-amino-6-(2-thienyl)-4-trifluoromethylthieno[2,3-b]pyridine-2-carboxylate (3) were prepared by reaction of 3-cyano-6-(2-thienyl)-4-trifluoromethylpyridine-2(1H)-thione (1) with ethyl chloroacetate. The reaction of both 2 and 3 with hydrazine hydrate under different conditions was studied. The main products were [3-cyano-6-(2-thienyl)-4-trifluoromethyl-2-pyridinylthio]acetohydrazide (4) and 3-amino-6-(2-thienyl)-4-trifluoromethylthieno[2,3-b]pyridine-2-carbohydrazide (5). The condensation of acethydrazide 4 with some aromatic or heterocyclic aldehydes yielded the corresponding hydrazones 6a–d which underwent intramolecular Thorpe–Ziegler cyclisation to give the N1-aryl or heteroaryl-methylene-3-amino-6-(2-thienyl)-4-trifluoromethylthieno[2,3-b]pyridine-2-carbohydrazides (7a–d). Treatment of 7a–d with triethyl orthoformate led to the formation of pyridothienopyrimidine derivatives 8a–d. Heating carbohydrazide 5 with acetic acid gave an unexpected product which was assigned as 3-amino-2-methyl-7-(2-thienyl)-9-trifluoromethylpyrido[3′,2′:4,5] thieno[3,2-d]pyrimidine-4(3H)-one (12). Moreover, the reaction of 5 with other reagents such as acetic anhydride, formic acid, acetylacetone and/or triethyl orthoformate were carried out and their products were identified. Diazotisation of 5 produced the corresponding acyl azide 18 which underwent Curtius rearrangement to furnish the imidazolone derivative 20. Hydrolysis of the ester 3 gave the aminoacid 21 which in turn was converted into the oxazinone derivatives 22 and 23. Recyclisation of 22 and 23 into some pyrimidinone derivatives (12 and 24–26) was carried out.

Studies on the Lignin of Eucalyptus regnans. II. The Nature of the Hydroxyl Groups and the Presence of the Carbonyl Group in Thiolignin

1948 ◽  
Vol 1 (2) ◽  
pp. 241
Author(s):  
JWT Merewether
Keyword(s):  
Benzoyl Chloride ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Carbonyl Groups ◽  
Eucalyptus Regnans ◽  
Trimethyl Ether ◽  
Free Hydroxyl ◽  
Active Methylene ◽  
Methylene Group ◽  
Alcoholic Hydroxyl

E. regnans thiolignin reacts with p-toluenesulphonyl chloride in pyridine to form a hexatosyl derivative ; its trimethyl ether reacts likewise to form a tritosyl derivative. Both compounds still have a free hydroxyl group which can be acetylated. Similarly they yield a hexabenzoate and tribenzoate respectively by the Schotten-Baumann reaction, but in pyridine, thiolignin reacts with benzoyl chloride to give a heptabenzoate and trimethylthiolignin a tetrabenzoate. No reaction takes place when trimethyl thiolignin is treated with triphenylchloromethane in pyridine. The above data are interpreted as evidence that of the four alcoholic hydroxyl groups three are secondary and one tertiary. With phenylhydrazine, thiolignin yields a phenylosazone ; with p-nitrophenylhydrazine it yields a p-nitrophenylhydrazone. On the other hand, trimethylthiolignin does not react with phenylhydrazine, indicating the absence of non-enolizable carbonyl groups. Thiolignin condenses with benzaldehydes indicating the presence of an active methylene group. From this evidence it is deduced that the grouping CH2-CO-CHOH- is present.

The Cardiac Glycosides of Gomphocarpus fruticosus R.Br. II. Gomphoside

1957 ◽  
Vol 10 (1) ◽  
pp. 79 ◽  
Author(s):  
RR Watson ◽  
SE Wright
Keyword(s):  
Acetic Acid ◽  
Absorption Spectra ◽  
Cardiac Glycosides ◽  
Chromium Trioxide ◽  
Periodic Acid ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Colour Reaction ◽  
Infra Red ◽  
Hydrolysis Of

Gomphoside is the second glycoside which has been isolated from Gomphocarpus fruticosus R.Br. grown in Australia. This compound analyses for the formula C29H44O8 and contains neither methoxyl nor acetyl groups, but forms a diacetate, C33H48O10, which is unstable to chromium trioxide in acetic acid. Although gomphoside gives a negative Keller-Kiliani reaction, a quantitative oxidation by periodic acid indicates the presence of two free adjacent hydroxyl groups in the molecule. Hydrolysis of gomphoside gives gomphogenin, C23H34O5, which does not give a colour reaction with tetranitromethane. The acetylation of gomphogenin yields acetylgomphogenin, C25H36O6, which is unstable to chromium trioxide in acetic acid. Gomphoside and its derivatives have ultraviolet and infra-red absorption spectra typical of those of the normal digitaloid compounds. The reactions which have been carried out on these substances indicate the presence of an hydroxyl group in gomphogenin, besides the normal hydroxyl groups at C3 and C14, which is resistant to acetylation, but which can be oxidized by chromium trioxide in acetic acid. The nature of the carbohydrate is as yet unknown.

Methylthiomethyl ethers: Their use in the protection and methylation of hydroxyl groups

1978 ◽  
Vol 31 (5) ◽  
pp. 1031 ◽  
Author(s):  
PM Pojer ◽  
SJ Angyal
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Dimethyl Sulfoxide ◽  
Methyl Iodide ◽  
Good Yield ◽  
Hydroxyl Groups ◽  
Nickel Boride ◽  
Tertiary Alcohols ◽  
Methylthiomethyl Ethers

Methylthiomethyl ethers are obtained in good yield from primary, secondary and tertiary alcohols by treating them with a mixture of dimethyl sulfoxide, acetic anhydride and acetic acid. The methyl- thiomethyl groups are readily removed on heating the compounds with methyl iodide in moist acetone. The methylthiomethyl ethers are converted into methyl ethers by the action of 'nickel boride'.

Simplified Rapid Technic for the Extraction and Determination of Serum Cholesterol without Saponification

1956 ◽  
Vol 2 (5) ◽  
pp. 353-368 ◽  
Author(s):  
Julius J Carr ◽  
I J Drekter
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Total Cholesterol ◽  
Simple Procedure ◽  
Cholesterol Esters ◽  
Color Development ◽  
Acid Catalyzed ◽  
Hydrolysis Of ◽  
Room Lighting

Abstract An accurate yet simple procedure for the determination of total cholesterol, based upon the application of a Liebermann-Burchard color reaction directly in the solvent employed for extraction of cholesterol from serum, has been described. Extraction of cholesterol and removal of protein are accomplished by means of acetic acid and acetic anhydride. Serum water is removed by the acid-catalyzed hydrolysis of acetic anhydride. The Liebermann-Burchard color is then developed with a stable, modified reagent consisting of equal volumes of H2SO4 and acetic acid. Excellent agreement with the technic of Schoenheimer and Sperry is obtained. Equal intensities of color are produced by equivalent concentrations of free and esterified cholesterol. Preliminary saponification of cholesterol esters is therefore not required. Color development may proceed in ordinary room lighting without loss of accuracy.

Studies on the Lignin of Eucalyptus regnans. III. The Isolation of an Alkali Lignin from Sulphate Pulping

1949 ◽  
Vol 2 (1) ◽  
pp. 117
Author(s):  
JWT Merewether
Keyword(s):  
Acetic Anhydride ◽  
Alkaline Hydrolysis ◽  
Empirical Formula ◽  
Benzoyl Chloride ◽  
Dimethyl Sulphate ◽  
Hydroxyl Groups ◽  
Equivalent Weight ◽  
Eucalyptus Regnans ◽  
Alkali Lignin ◽  
Hydrolysis Of

An alkali lignin containing no sulphur has been obtained as a by-product from the sulphate pulping of Eucalyptus regnans. Like other alkali lignins it contains hydroxyl groups, both acidic and alcoholic, as well as methoxyl groups. Acetic anhydride in pyridine yields an octoacetyl derivative which is readily hydrolysed by boiling water to a heptacetyl derivative. In pyridine, benzoyl chloride yields an octobenzoyl derivative while in aqueous alkali it yields a hexabenzoyl compound. Dimethyl sulphate yields a heptamethyl alkali lignin, diazomethane a hexamethyl derivative, while cold alkaline hydrolysis of the latter gives a pentamethyl derivative, and hot alkaline hydrolysis yields an anhydrotrimethyl alkali lignin. One of the methoxyl groups formed by methylation is unstable to acetylation by acetic anhydride in pyridine, heptamethyl alkali lignin yielding a hexamethyldiacetyl derivative, hexamethyl alkali lignin a pentamethyltriacetyl derivative, pentamethyl alkali lignin a tetramethyltetracetyl derivative, and anhydrotrimethyl alkali lignin the corresponding anhydrodimethyltetracetyl alkali lignin. Triphenylchloromethane in pyridine yields a monotrityl derivative.p-Nitrophenylhydrazine gives a di-p-nitrophenylhydrazone and phenylhydrazine a phenylhydrazone-osazone. Potentiometric titration shows two points of inflection and an equivalent weight of 863. The data are consistent with the empirical formula C92Hl04O34(1754) or C73H54O9,(OCH3)14,(OH)3,C(OH),CO-CH20H,C0,COOH

Hydrolysis of Acetic Anhydride in Concentrated Acetic Acid without Catalysis

1957 ◽  
Vol 49 (2) ◽  
pp. 197-201 ◽  
Author(s):  
H. J. Janssen ◽  
C. H. Haydel ◽  
L. H. Greathouse
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Hydrolysis Of
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