STUDIES ON REACTIONS RELATING TO CARBOHYDRATES AND POLYSACCHARIDES: XLIII. CYCLIC ACETAL AND KETAL FORMATION FROM α-PHENYL GLYCEROL AS FURTHER EXAMPLES OF THE "RING PARTITION PRINCIPLE"

1932 ◽  
Vol 7 (6) ◽  
pp. 629-642 ◽  
Author(s):  
Muriel E. Platt ◽  
Harold Hibbert
Keyword(s):  
Methyl Ether ◽  
Condensation Product ◽  
Direct Synthesis ◽  
Cyclic Acetal ◽  
Partition Theory ◽  
Ring Compounds ◽  
Viscous Oil ◽  
Partition Principle ◽  
Isopropylidene Derivatives ◽  
Crystalline Forms

The work represents an extension of the "Hibbert-Michael ring partition theory" to the interaction of α-phenyl glycerol with acetone and p-nitrobenzaldehyde respectively. The α-phenyl glycerol was prepared in the form of a pure crystalline product from cinnamyl alcohol and on condensation with acetone yielded the two expected, isomeric, five-membered (dioxolane) ring compounds. These two isopropylidene derivatives were isolated and their structures definitely determined by the usual hydrolysis and methylation technique. In this manner the corresponding α- and γ-methyl ethers of α-phenyl glycerol were isolated, the identity of which had been previously settled by direct synthesis employing well-established reactions.The β-methyl ether of α-phenyl glycerol was obtained by methylating crystalline 1:3 p-nitrobenzylidene α-phenyl glycerol and then hydrolyzing the ether.Condensation of p-nitrobenzaldehyde with α-phenyl glycerol should yield, according to the "ring partition principle", one six- and two five-membered cyclic acetals.The crystalline isomer separating from the crude condensation product was shown to be the six-membered cyclic acetal. Removal of this left a viscous oil containing the five-membered acetals which, on methylation, and subsequent hydrolysis, yielded a small amount of the γ-methyl ether of α-phenyl glycerol, thus indicating the presence of some 1:2 p-nitrobenzylidene glycerol in the original reaction product. Due to the large number of theoretically possible five-membered rings it was not found possible to isolate, or prove the presence of, both five-membered acetals in the oil left after removal of the crystalline six-membered acetal. Presumably both of the structural five-membered acetals were formed, but due to their mutual solubility relations it was not possible to bring about a separation of crystalline forms.

scholarly journals Clean Enzymatic depolymerization of highly crystalline polyethylene terephthalate in moist-solid reaction mixtures

2020 ◽  
Author(s):  
Sandra Kaabel ◽  
J. P. Daniel Therien ◽  
Catherine E. Deschênes ◽  
Dustin Duncan ◽  
Tomislav Friščić ◽  
...  
Keyword(s):  
Polyethylene Terephthalate ◽  
Metal Organic Framework ◽  
Direct Synthesis ◽  
Plastic Pollution ◽  
Solid Reaction ◽  
Pollution Problem ◽  
Metal Organic ◽  
Dilute Aqueous Solutions ◽  
Space Time Yield ◽  
Crystalline Forms

AbstractLess than 9% of the plastic produced is recycled after use, contributing to the global plastic pollution problem. While polyethylene terephthalate (PET) is one of the most common plastics, its thermomechanical recycling generates a material of lesser quality. Enzymes are highly selective, renewable catalysts active at mild temperatures; however, the current consensus is that they lack activity towards the more crystalline forms of PET. We report here that when used in moist-solid reaction mixtures instead of the typical dilute aqueous solutions, enzymes can directly depolymerize high crystallinity PET in 13-fold higher space-time yield and a 15-fold higher enzyme efficiency than prior reports. Further, this process shows a 26-fold selectivity for terephthalic acid over other hydrolysis products, which allows the direct synthesis of UiO-66 metal-organic framework.

STUDIES OF REACTIONS RELATING TO CARBOHYDRATES AND POLYSACCHARIDES.: XXVIII. THE STRUCTURE OF ISOPROPYLIDENE GLYCEROL

1930 ◽  
Vol 2 (3) ◽  
pp. 214-217 ◽  
Author(s):  
Harold Hibbert ◽  
J. G. Morazain
Keyword(s):  
Methyl Iodide ◽  
Methyl Ether ◽  
Copper Sulphate ◽  
Silver Oxide ◽  
Condensation Product ◽  
Neutral Medium ◽  
Physico Chemical ◽  
Isopropylidene Glycerol

Isopropylidene glycerol, prepared in neutral medium by the action of anhydrous copper sulphate as condensing agent, was methylated with silver oxide and methyl iodide; the product yielded only glycerol α-methyl ether on hydrolysis, thus proving the absence of any six-membered ketal in the condensation product of glycerol and acetone.The properties of both glycerol α- and β-methyl ethers have been carefully redetermined.A table of the isomeric acetals and ketals summarising their physico-chemical constants is given, in view of their usefulness as "type compounds" in investigations relating to fats, carbohydrates and polysaccharides.

The reaction of isopropenyl methyl ether with aldohexoses and their derivatives

1978 ◽  
Vol 31 (6) ◽  
pp. 1371 ◽  
Author(s):  
C Copeland ◽  
RV Stick
Keyword(s):  
Methyl Ether ◽  
Isopropylidene Derivatives

Methyl α-D-mannopyranoside, D-mannose, D-gulose and D-galactose have been converted into their 4,6-O-isopropylidene derivatives by use of isopropenyl methyl ether. The same reagent converts D-gulono- and D- galactono-1,4-lactones into their 5,6-O-isopropylidene derivatives.

A SYNTHESIS OF 1-HYDROXY-2-NAPHTHOIC NITRILE

1937 ◽  
Vol 15b (11) ◽  
pp. 480-485 ◽  
Author(s):  
John A. McRae ◽  
Léo Marion
Keyword(s):  
Ethyl Alcohol ◽  
Methyl Ether ◽  
Condensation Product ◽  
Neutral Product ◽  
Low Pressures

The neutral product of the condensation of phenylacetaldehyde with ethyl sodiocyanoacetate when distilled under low pressures loses the elements of ethyl alcohol and forms 1-hydroxy-2-naphthoic nitrile. This is identical with the synthetic substance prepared through a series of reactions from α-naphthol. The methyl ether has been prepared from both the synthetic substance and the product of the condensation. 1-Hydroxy-2-naphthoic nitrile can be coupled readily with p-nitrobenzenediazonium chloride. The evidence relating to the structure of the neutral condensation product is reviewed.

STUDIES ON REACTIONS RELATING TO CARBOHYDRATES AND POLYSACCHARIDES. XXVII. SYNTHESIS AND STRUCTURE OF TRICHLOROETHYLIDENE GLYCEROL

1930 ◽  
Vol 2 (2) ◽  
pp. 131-143 ◽  
Author(s):  
Harold Hibbert ◽  
J. G. Morazain ◽  
A. Paquet
Keyword(s):  
Sulphuric Acid ◽  
Methyl Ether ◽  
Ring Closure ◽  
Cyclic Acetal ◽  
Satisfactory Explanation ◽  
Carbonyl Derivative ◽  
Cyclic Acetals ◽  
Polyhydroxy Compounds

A discussion is given as to the nature of the factors involved in the mechanism of the formation of cyclic acetals and ketals from carbonyl and polyhydroxy derivatives. It is shown that in the two reactions involved, namely, the primary formation of a half-acetal, followed by removal of water and ring-closure, the polarity of the carbonyl derivative plays a very important rôle. Chloral combines with polyhydroxy compounds to give exceptionally stable half-acetals, which can be converted into the cyclic derivatives by the use of strong dehydrating agents.In contrast with the behavior of other aldehydes it is found that the condensation of chloral with glycerol yields only one ring compound, namely the five-membered derivative. No satisfactory explanation of this can, as yet, be given.The identity of the trichloroethylidene glycerol obtained by the condensation of glycerol and chloral under the influence of concentrated sulphuric acid has been established as a five-membered cyclic acetal by a comparison of the properties of its methyl ether with those of trichloroethylidene glycerol α-methyl ether prepared from glycerol α-methyl ether.

Characterization of Chemical Impurities in Glutaraldehyde

1975 ◽  
Vol 33 ◽  
pp. 620-621
Author(s):  
B. J. Grenon ◽  
A. J. Tousimis
Keyword(s):  
Glutaric Acid ◽  
Spectroscopic Analysis ◽  
Aldol Condensation ◽  
Condensation Product ◽  
Amorphous Solid ◽  
Water Soluble ◽  
Impurity Component ◽  
Chemical Impurities ◽  
Soluble Liquid

Ever since the introduction of glutaraldehyde as a fixative in electron microscopy of biological specimens, the identification of impurities and consequently their effects on biologic ultrastructure have been under investigation. Several reports postulate that the impurities of glutaraldehyde, used as a fixative, are glutaric acid, glutaraldehyde polymer, acrolein and glutaraldoxime.Analysis of commercially available biological or technical grade glutaraldehyde revealed two major impurity components, none of which has been reported. The first compound is a colorless, water-soluble liquid with a boiling point of 42°C at 16 mm. Utilizing Nuclear Magnetic Resonance (NMR) spectroscopic analysis, this compound has been identified to be — dihydro-2-ethoxy 2H-pyran. This impurity component of the glutaraldehyde biological or technical grades has an UV absorption peak at 235nm. The second compound is a white amorphous solid which is insoluble in water and has a melting point of 80-82°C. Initial chemical analysis indicates that this compound is an aldol condensation product(s) of glutaraldehyde.

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