The composition of grape cuticle wax

1965 ◽  
Vol 18 (7) ◽  
pp. 1059 ◽  
Author(s):  
F Radler ◽  
DHS Horn
Keyword(s):  
Fatty Acids ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Oleanolic Acid ◽  
Light Petroleum ◽  
Oxidation Products ◽  
Straight Chain ◽  
Neutral Alumina ◽  
Chain Lengths ◽  
Long Chain

The cuticle wax of the grape is composed of a soft wax (30%) readily removed by light petroleum and a hard wax (30%), mainly oleanolic acid, removed by chloroform. The soft wax of the fresh grape is composed chiefly of long-chain alcohols together with smaller amounts of aldehydes, esters, fatty acids, hydrocarbons, oleanolic acid, and small amounts of high molecular weight substances. The soft wax of dried grapes is similar in composition but contains no aldehydes and larger amounts of high molecular weight substances and oxidation products. The aldehydes, unusual wax components, are straight chain and range from C16 to C32 with the even chain-lengths predominating. They were destroyed by neutral alumina but can be chromatographed on silicic acid.

THE APPLICATION OF THE ARNDT–EISTERT REACTION TO THE SYNTHESIS OF FATTY ACIDS OF HIGH MOLECULAR WEIGHT

1950 ◽  
Vol 28b (9) ◽  
pp. 556-560 ◽  
Author(s):  
F. A. Vandenheuvel ◽  
P. Yates
Keyword(s):  
Fatty Acids ◽  
Molecular Weight ◽  
Carboxylic Acid ◽  
Stearic Acid ◽  
High Molecular Weight ◽  
Efficient Method ◽  
Convenient Method ◽  
Ultraviolet Absorption ◽  
Aliphatic Carboxylic Acid ◽  
Eicosanoic Acid

The Arndt–Eistert reaction offers a convenient method for the synthesis of the higher members of the aliphatic carboxylic acid series. Nonadecanoic acid, eicosanoic acid, and heneicosanoic acid have been prepared successively from stearic acid in good yields. An efficient method of purification of the synthetic products is described. The ultraviolet absorption maxima for some diazoketones derived from the higher members of the aliphatic carboxylic acid series are recorded.

Spectral study on the oxidation products of conjugated dienes of high molecular weight

1965 ◽  
Vol 6 (1) ◽  
pp. 38-42
Author(s):  
R. M. Aseeva ◽  
Yu. G. Aseev ◽  
A. A. Berlin ◽  
V. I. Kasatochkin
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Spectral Study ◽  
Conjugated Dienes ◽  
Oxidation Products

scholarly journals The occurrence of polyenoic very long chain fatty acids with greater than 32 carbon atoms in molecular species of phosphatidylcholine in normal and peroxisome-deficient (Zellweger's syndrome) brain

1988 ◽  
Vol 253 (3) ◽  
pp. 645-650 ◽  
Author(s):  
A Poulos ◽  
P Sharp ◽  
D Johnson ◽  
C Easton
Keyword(s):  
Fatty Acids ◽  
Molecular Species ◽  
Carbon Chain ◽  
Normal Brain ◽  
Long Chain Fatty Acids ◽  
Brain Physiology ◽  
Chain Lengths ◽  
The Brain ◽  
Long Chain ◽  
Chain Fatty Acids

The n-6 tetra- and pentaenoic fatty acids with carbon chain lengths greater than 32 found in normal brain are located predominantly in a separable species of phosphatidylcholine. A similar phospholipid is found in increased amounts in the brain of peroxisome-deficient (Zellweger's syndrome) patients, but the fatty acid composition differs in that penta- and hexaenoic derivatives predominate. Our data strongly suggest that the polyenoic very long chain fatty acids are confined to the sn-1 position of the glycerol moiety, while the sn-2 position is enriched in saturated, monounsaturated and polyunsaturated fatty acids with less than 24 carbon atoms. It is postulated that these unusual molecular species of phosphatidylcholine may play some, as yet undefined, role in brain physiology.

Ligand-Unsymmetrical Phenoxyiminato Dinickel Catalyst for High Molecular Weight Long-Chain Branched Polyethylenes

2015 ◽  
Vol 4 (11) ◽  
pp. 1297-1301 ◽  
Author(s):  
Dongxu Shu ◽  
Aidan R. Mouat ◽  
Casey J. Stephenson ◽  
Anna M. Invergo ◽  
Massimiliano Delferro ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Long Chain

Behavior of Rubber Hydrocarbon in a Molecular Still

1939 ◽  
Vol 12 (4) ◽  
pp. 789-793 ◽  
Author(s):  
W. Harold Smith ◽  
Henry J. Wing
Keyword(s):  
Molecular Weight ◽  
Vapor Pressure ◽  
High Molecular Weight ◽  
Molecular Species ◽  
Decomposition Temperature ◽  
Sedimentation Equilibrium ◽  
Chain Molecules ◽  
Molecular Weights ◽  
Average Value ◽  
Long Chain

Abstract Some investigators believe that rubber consists of associated molecules, and others accept Staudinger's view that long-chain molecules are formed by polymerization. Pummerer, Andriessen and Gündel have obtained a molecular weight as low as 600. Meyer and Mark believe that it is approximately 5,000, although they calculated on the basis of osmotic pressures values as high as 350,000. They, as well as Pummerer, consider that rubber is an associated colloid and that high molecular weights are caused by aggregates, sometimes called micelles. Staudinger, however, considers that the long-chain rubber molecule itself has a molecular weight of 200,000 or even 350,000, and that products with lower values, which may be formed in rubber, result from degradation. if the molecules are small it might be possible to distil them if their vapor pressure could be sufficiently increased, but none would distil without decomposition if the molecules are very large. Because the vapor pressure of rubber below its decomposition temperature is low, it appeared of interest to attempt to distil the material in a molecular still. Paraffin wax and sugar, both substances of relatively high molecular weight, have been successfully distilled in this type of apparatus. Subsequent to the work described in this paper, the molecular weight of sol rubber prepared at this Bureau was determined by Kraemer and Lansing of E. I. du Pont de Nemours & Co., Inc. They used the Svedberg method of sedimentation equilibrium in an ultracentrifuge with ethereal solutions of sol rubber. The temperature of the solutions during determinations was approximately 10° C, and an average value of 460,000 was obtained. There was evidenced of a mixture of molecular species.

scholarly journals Unique molecular species of phosphatidylcholine containing very-long-chain (C24-C38) polyenoic fatty acids in rat brain

1990 ◽  
Vol 265 (3) ◽  
pp. 763-767 ◽  
Author(s):  
B S Robinson ◽  
D W Johnson ◽  
A Poulos
Keyword(s):  
Fatty Acids ◽  
Rat Brain ◽  
Molecular Species ◽  
Carbon Chain ◽  
Neonatal Rat ◽  
Adult Rat ◽  
Adult Rat Brain ◽  
Chain Lengths ◽  
Neonatal Rat Brain ◽  
Long Chain

Rat brain has been shown to contain polyenoic very-long-chain fatty acids (VLCFA) belonging to the n-3 and n-6 series with four, five and six double bonds and even-carbon chain lengths from 24 to 38. These fatty acids are almost exclusively located in unusual molecular species of phosphatidylcholine at the sn-1 position of the glycerol backbone, whereas saturated, monoenoic and polyenoic fatty acids with less than 24 carbon atoms are present at the sn-2 position. Polyenoic VLCFA phosphatidylcholine in neonatal rat brain is enriched with n-6 pentaenoic and n-3 hexaenoic VLCFA with up to 36 carbon atoms, whereas the corresponding phospholipid in adult rat brain mainly contains n-6 tetraenoic and n-3 pentaenoic VLCFA with up to 38 carbon atoms. The total amount of polyenoic VLCFA associated with phosphatidylcholine is highest in the brain of immature animals. Polyenoic VLCFA phosphatidylcholine appears to be predominantly confined to nervous tissue in rats, and it is envisaged that this phospholipid is of physiological significance.

Relationship between trisaturated glyceride composition and the softening point of milk fat

1979 ◽  
Vol 46 (4) ◽  
pp. 633-639 ◽  
Author(s):  
Peter W. Parodi
Keyword(s):  
Fatty Acids ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Milk Fat ◽  
Softening Point ◽  
Correlation Coefficients ◽  
Low Molecular Weight ◽  
Excellent Correlation ◽  
Trisaturated Glyceride ◽  
Glyceride Fraction

SummaryNo relationship was found between the trisaturated glyceride content and the softening point (SP) of milk fat. Inter-esterification of milk fat increased its SP, but did not change the trisaturated glyceride content or the fatty acid composition of the trisaturated glyceride fraction. Inter-esterification increased the amount of both low and high and decreased the amount of medium molecular weight triglyceride species in the trisaturated glyceride fraction. The increase in the amount of high molecular weight triglyceride species was up to 3 times greater than the increase in the amount of low molecular weight triglycerides.The triglyceride species composition of the trisaturated glyceride fraction of milk fat was found to vary seasonally. Excellent correlation was found between SP and groups of low molecular weight triglycerides, groups of high molecular weight triglycerides and some individual triglyceride species. Correlation coefficients were higher than those previously reported between groups of fatty acids and SP.

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