STRUCTURE OF A HEMICELLULOSE FROM MAPLE WOOD PREVIOUSLY EXTRACTED BY LIQUID AMMONIA

The extraction of maple wood meal with anhydrous liquid ammonia under pressure near 20° altered the wood in such a way that an additional small amount of lignin could be extracted with ethanol, and 1.9% of crude hemicelluloses with hot water. An additional 0.25% of nitrogen was retained, apparently as insoluble amides, by the residual wood. After elimination of pectic material by acetylation, the three subtractions of the hemicellulose acetate had identical specific rotations of −61 ± 1° in chloroform; all three corresponded in composition to a combination of one methylglucuronic anhydride to six anhydroxylose units. A conventional study by the methylation method suggested that the hemicellulose was a branched-chain structure averaging four anhydroxylose units linked 1—4, with one also substituted in the second position, and another linked 1—3.

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Effect of Surfactant Molecular Structure on Emulsion Stability Investigated by Interfacial Dilatational Rheology

Polymers ◽

10.3390/polym13071127 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1127

Author(s):

Yuejie Jin ◽

Dingrong Liu ◽

Jinhua Hu

Keyword(s):

Emulsion Stability ◽

Chain Structure ◽

Interfacial Film ◽

Future Design ◽

Rheological Method ◽

Viscoelastic Modulus ◽

Hydrophobic Chain ◽

Branched Chain ◽

The Stability ◽

Branched Structure

Polyglycerol polyricinolate (PGPR) and polyglycerol-2 dioleate were selected as model surfactants to construct water-in-oil (W/O) emulsions, and the effect of interfacial rheological properties of surfactant film on the stability of emulsions were investigated based on the interfacial dilatational rheological method. The hydrophobicity chain of PGPR is polyricinic acid condensed from ricinic acid, and that of polyglycerol-2 dioleate is oleic acid. Their dynamic interfacial tensions in 15 cycles of interfacial compression-expansion were determined. The interfacial dilatational viscoelasticity was analyzed by amplitude scanning in the range of 1–28% amplitude and frequency sweep in the range of 5–45 mHz under 2% amplitude. It was found that PGPR could quickly reach adsorption equilibrium and form interfacial film with higher interfacial dilatational viscoelastic modulus to resist the deformation of interfacial film caused by emulsion coalescence, due to its branched chain structure and longer hydrophobic chain, and the emulsion thus presented good stability. However, polyglycerol-2 dioleate with a straight chain structure had lower interfacial tension, and it failed to resist the interfacial disturbance caused by coalescence because of its lower interfacial dilatational viscoelastic modulus, and thus the emulsion was unstable. This study reveals profound understanding of the influence of branched structure of PGPR hydrophobic chain on the interfacial film properties and the emulsion stability, providing experimental reference and theoretical guidance for future design or improvement of surfactant.

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AMMONOLYSIS OF URONIC ESTER GROUPS IN BIRCH XYLAN

Canadian Journal of Chemistry ◽

10.1139/v64-358 ◽

1964 ◽

Vol 42 (11) ◽

pp. 2434-2439 ◽

Cited By ~ 29

Author(s):

Paul Y. Wang ◽

H. I. Bolker ◽

C. B. Purves

Keyword(s):

Alkaline Hydrolysis ◽

Uronic Acid ◽

Liquid Ammonia ◽

Treated Wood ◽

Hot Water ◽

Amide Nitrogen ◽

White Birch

Solvent-extracted white birch, kept near 20° in liquid ammonia under pressure for 72 h and then extracted with methanol to remove acetamide, retained 0.25% of amide nitrogen. Extraction of the very finely ground residual wood with hot water yielded 21% as a 4-O-methylglucuronoxylan containing 0.53% of amide nitrogen. Alkaline hydrolysis removed the amide absorption in the infrared and restored the normal xylan spectrum. These results, supported by various control experiments, showed that amide groups in the ammonia-treated wood were derived from lactone or ester groups in the original 4-O-methylglucuronoxylan. Some of the uronic acid groups in the native wood presumably existed as ester crosslinks.

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STUDIES ON REACTIONS RELATING TO CARBOHYDRATES AND POLYSACCHARIDES: LXI. PROPERTIES OF THE FRACTIONATED NITRATES OF TWO FRACTIONS OF CORN STARCH

Canadian Journal of Research ◽

10.1139/cjr46b-033 ◽

1946 ◽

Vol 24b (5) ◽

pp. 246-253 ◽

Cited By ~ 5

Author(s):

W. R. Ashford ◽

T. H. Evans ◽

Harold Hibbert

Keyword(s):

Relative Stability ◽

Corn Starch ◽

Chain Structure ◽

Linear Type ◽

Relative Stabilities ◽

Preferential Adsorption ◽

Chain Fraction ◽

Branched Chain ◽

Nitrogen Contents

Corn starch has been separated into two individual components, arbitrarily designated as amylose (linear fraction) and amylopectin (branched-chain fraction) by means of preferential adsorption on cellulose (Tanret–Pacsu method). These components have been nitrated and their nitrates fractionated by dissolution in ethanol. The relative stabilities and nitrogen contents of the nitrated fractions have been studied.Unfractionated amylose nitrate has greater stability than unfractionated amylopectin nitrate as judged by the Bergmann–Junk test. Dissolution methods of fractionation showed a much higher solubility of the amylopectin nitrate, the greater relative stability of the amylose fractions, and the somewhat greater stabilizing action of ethanol in the case of the latter.The widely different solubilities of amylose and amylopectin nitrates in conjunction with the lower ethanol solubility of whole starch nitrate are in accordance with the theory of a branched-chain structure for amylopectin and the linear type for amylose.

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Sacrificial amphiphiles: Eco-friendly chemical herders as oil spill mitigation chemicals

Science Advances ◽

10.1126/sciadv.1400265 ◽

2015 ◽

Vol 1 (5) ◽

pp. e1400265 ◽

Cited By ~ 27

Author(s):

Deeksha Gupta ◽

Bivas Sarker ◽

Keith Thadikaran ◽

Vijay John ◽

Charles Maldarelli ◽

...

Keyword(s):

Crude Oil ◽

Oil Spill ◽

Oil Spills ◽

Cold Water ◽

Marine Ecosystem ◽

Hot Water ◽

Sea Surface ◽

Marine Biota ◽

Polar Group ◽

Branched Chain

Crude oil spills are a major threat to marine biota and the environment. When light crude oil spills on water, it forms a thin layer that is difficult to clean by any methods of oil spill response. Under these circumstances, a special type of amphiphile termed as “chemical herder” is sprayed onto the water surrounding the spilled oil. The amphiphile forms a monomolecular layer on the water surface, reducing the air–sea surface tension and causing the oil slick to retract into a thick mass that can be burnt in situ. The current best-known chemical herders are chemically stable and nonbiodegradable, and hence remain in the marine ecosystem for years. We architect an eco-friendly, sacrificial, and effective green herder derived from the plant-based small-molecule phytol, which is abundant in the marine environment, as an alternative to the current chemical herders. Phytol consists of a regularly branched chain of isoprene units that form the hydrophobe of the amphiphile; the chain is esterified to cationic groups to form the polar group. The ester linkage is proximal to an allyl bond in phytol, which facilitates the hydrolysis of the amphiphile after adsorption to the sea surface into the phytol hydrophobic tail, which along with the unhydrolyzed herder, remains on the surface to maintain herding action, and the cationic group, which dissolves into the water column. Eventual degradation of the phytol tail and dilution of the cation make these sacrificial amphiphiles eco-friendly. The herding behavior of phytol-based amphiphiles is evaluated as a function of time, temperature, and water salinity to examine their versatility under different conditions, ranging from ice-cold water to hot water. The green chemical herder retracted oil slicks by up to ~500, 700, and 2500% at 5°, 20°, and 35°C, respectively, during the first 10 min of the experiment, which is on a par with the current best chemical herders in practice.

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New Route to Branched-chain Aminodeoxy Sugars by Reaction of Ketoses with Acetonitrile. Synthesis of Methyl 3-C-2′-Aminoethyl-2-deoxy-α-D-arabino-hexopyranoside

Canadian Journal of Chemistry ◽

10.1139/v74-008 ◽

1974 ◽

Vol 52 (1) ◽

pp. 51-54 ◽

Cited By ~ 4

Author(s):

Alex Rosenthal ◽

G. Schöllnhammer

Keyword(s):

Catalytic Hydrogenation ◽

Liquid Ammonia ◽

High Yield ◽

Lithium Amide ◽

Branched Chain

Addition of methyl 4,6-O-benzylidene-2-deoxy-α-D-erythro-hexopyranosid-3-ulose (1) to acetonitrile in liquid ammonia at −50 to −60° in the presence of lithium amide gave, in high yield, crystalline methyl 4,6-O-benzylidene-3-C-cyanomethyl-2-deoxy-α-D-arabino-hexopyranoside (2) exclusively. The proof of structure 2 is described. Debenzylidenation of 2 afforded the branched-chain cyano glycoside 3. Compound 3 was converted into its 3,4,6-tri-O-acetate (8) and 4,6-di-O-p-nitrobenzoate (9) derivatives. Catalytic hydrogenation of 3 over rhodium on alumina yielded methyl 3-C-2′-aminoethyl-2-deoxy-α-D-arabino-hexopyranoside which was characterized as its N-2,4-dinitrophenyl derivative (7).

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Chemiluminescence parameters of peroxynitrous acid in the presence of short-chain alcohols and Ru(bpy)32+

Chemical Papers ◽

10.2478/s11696-011-0081-7 ◽

2011 ◽

Vol 65 (6) ◽

Author(s):

Lijun Wei ◽

Huifen Xia ◽

Zhaopin Wang ◽

Ping Yuan ◽

Tong Zhou ◽

...

Keyword(s):

Excited State ◽

Carbon Chain ◽

Chain Structure ◽

Short Chain ◽

Peroxynitrous Acid ◽

Optimum Conditions ◽

Chemiluminescence Intensity ◽

Branched Chain

AbstractThe chemiluminescence behaviour and mechanism of peroxynitrous acid and Ru(bpy)32+ were studied in the presence of short-chain alcohols (methanol, ethanol, propan-1-ol, propan-2-ol, butanol, 2-methylpropan-1-ol, pentanol). It was found that the chemiluminescence intensity of peroxynitrous acid and Ru(bpy)32+ system could be significantly enhanced by these seven short-chain alcohols. The maximum chemiluminescence wavelength of 608 nm of [Ru(bpy)32+]* in the excited state was attributed to the reaction between Ru(bpy)32+ and dihydroxyalkyl radicals which were generated during the redox course of peroxynitrous acid and alcohols. In addition, the chemiluminescence signals of the system presented depended largely on the solubility and branched-chain structure as well as the length of carbon chain. The analytical characteristics and parameters of the peroxynitrous acid/Ru(bpy)32+/alcohols chemiluminescence system were investigated under optimum conditions.

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