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Friday, November 6, 2020 | History

2 edition of Studies on homologous series of oligomeric antioxidants. found in the catalog.

Studies on homologous series of oligomeric antioxidants.

Graham John Knight

Studies on homologous series of oligomeric antioxidants.

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  • 13 Currently reading

Published by University of Salford in Salford .
Written in English


Edition Notes

PhD thesis, Chemistry.

SeriesND2295/72
ID Numbers
Open LibraryOL20308801M

A prune extract was separated by an antioxidant-guided assay to obtain an oligomeric proanthocyanidin fraction. The antioxidative oligomer was characterized as a procyanidin oligomer with an average polymerization degree of five and composed of epicatechin and catechin by: homologous series (plural homologous series) any series of aliphatic organic compounds whose members differ only in the addition of a CH 2 group; for example, the carboxylic acids, CH 3 (CH 2) n COOH where n is any whole number.


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Studies on homologous series of oligomeric antioxidants. by Graham John Knight Download PDF EPUB FB2

Studies on homologous series of oligomeric antioxidants derived from p‐cresol/formaldehyde condensates. Evaluation in polystyrene M. Huglin. Materials Department, Royal Aircraft Establishment, Farnborough, Hants, England.

Department of Chemistry and Applied Chemistry, University of Salford, Lancashire, by: 1. Studies on homologous series of oligomeric antioxidants derived from p‐cresol/formaldehyde condensates.

III. Evaluation in an ethylene/propylene copolymer. Studies on homologous series of oligomeric antioxidants Author: Knight, Graham John. Studies on homologous series of oligomeric antioxidants derived from p‐cresol/formaldehyde condensates. III. Evaluation in an ethylene/propylene copolymer M.

Huglin; Edna Kay; G. Knight; W. Wright; Pages: ; First Published: 18 February What five things do homologous series have in common. [5] What happens to (a) BP and (b)MP and (c) reactivity (d) solubility as the carbon chain gets longer chain gets longer.

[4] Give the functional group of the following series (a) aldehydes (b) alkenes (c) alkynes (d) alcohols (e) carboxylic acids [5]. Melting points of the homologous series showed an odd–even alternating effect for alkyl chains longer than four CH2 units.

The TGA of n-alkylPOSS under nitrogen showed that the thermal stability temperatures are between and ° by: This series has enabled scientists and engineers to study different organic compounds in a systematic manner. They can predict the properties of organic compounds belonging to a particular homologous series based on the data available from the other members of the same series.

The study of organic compounds has been simplified. Studies on homologous series of oligomeric antioxidants. book There are a number of homologous series in organic compounds. Some important series of aliphatic compounds are listed below: If we examine the unbranched alkanes, we notice that each alkane differs from the preceding alkane by one —CH 2 — group.

Butane, for example, is CH 3 (CH 2) 2 CH 3 and pentane is CH 3 (CH 2) 3 CH room temperature (25°C) and 1 atm pressure, the first four. The present study describes the influence of the different stages of a lab-scale chocolate manufacturing process on the content of oligomeric proanthocyanidins and their antioxidant capacity.

The sum of the total proanthocyanidin content (∑ DP1-DP13) decreased from 30 mg epicatechin equivalents per gram non-fat dry matter in raw fresh cocoa beans to 6 mg epicatechin equivalents per gram in the final Cited by: Especially individual oligomeric proanthocyanidins demonstrated a significant contribution to the total antioxidant activity of cocoa compared to monomeric compounds.

An NP-HPLC-online-DPPH assay was developed for separating the homologous series of oligomeric proanthocyanidins and the simultaneous assessment of their antioxidant capacity in Cited by: The crystal structures of four homologous series of rod-like molecules are reviewed, two of which form hydrogen bonds and two with a symmetric chemical constitution.

Many of the compounds investigated turn into liquid crystalline phases upon temperature increase. It is of valuable interest to know possible conformations and possible packing arrangements as prerequisites to model liquid Cited by: 3.

In wild habitats, fruit dehiscence is a critical strategy for seed dispersal; however, in cultivated crops it is one of the major sources of yield loss. Therefore, indehiscence of fruits, pods, etc., was likely to be one of the first traits strongly selected in crop domestication.

Even with the historical selection against dehiscence in early domesticates, it is a trait still targeted in many Cited by: 5. Oligomers without end groups are readily separated into oligomer homologues on polar adsorbents by adsorption chromatography.

It is also easy to separate according to MM, oligomers with end groups for which the energies of interaction with adsorbent for the central (ε c) and end (ε e) units are similar.

The criteria are given that enable one to distinguish between the ranges of monomers, oligomers and polymers in homologous series. Theoretical aspects of a small-scale oligomer structure of and models for the formation of the supermolecular and the organization of liquid oligomeric systems are presented.

Cocoa beans are a well-known source of antioxidant polyphenols. Especially individual oligomeric proanthocyanidins demonstrated a significant contribution to the total antioxidant activity of cocoa compared to monomeric compounds.

An NP-HPLC-online-DPPH assay was developed for separating the homologous series of oligomeric proanthocyanidins and the simultaneous assessment of their antioxidant.

Therefore, an efficient methodology for the purification of oligomeric procyanidins with defined DP has been established in order to obtain sufficient amounts of test compounds for detailed structure-activity studies.

During the large scale purification of defined OPCs, a further homologous series of oligomeric cinchonains has been identified Cited by: Nature's chemistry Hydrocarbons and homologous series.

A homologous series is a family of hydrocarbons with similar chemical properties who share the same general formula. homologous series of condensed polyphenols for assessing their antioxidant capacity in relation to their degree of polymerisation (DP), simultaneously.

In this context, normal-phase chromatography allows separations of polyphenols based on their degree of polymerisation. This study showed that an unroasted cocoa extract contains condensedFile Size: KB. Functional groups and homologous series 10 ORGANIC CHEMISTRY HOMOLOGOUS SERIES The alkanes form a series of compounds all with the general formula C n H 2n+2, e.g.

methane CH 4 ethane C 2H 6 propane C 3H 8 butane C 4H 10 If one of the hydrogen atoms is removed what is left is known as an alkyl radical R – (e.g methyl CH 3 –; ethyl C 2 H 5 –).File Size: KB. Previous studies have shown that oil of M. pulegium varies within and among geogra phic -climatic zones [12, 13 ].

Pulegone ( ±%) constitutes the major compound of this oil [12, 14 ]. This study to identify the chemical composition of the essential oil of the mint commonly. In chemistry, a homologous series is a series of chemical compounds with the same general formula.

Usually these compounds vary by a single parameter such as the length of a carbon chain. Examples of such series are the straight-chained alkanes (paraffins), and some of their derivatives (such as the primary alcohols, aldehydes, and (mono)carboxylic acids).

Cyperus rotundus L. (Cyperaceae) is a medicinal herb traditionally used to treat various clinical conditions at home. In this study, chemical composition Cited by: 7.

In this video, we look at what a homologous series is, and how we can group different organic compounds into the same homologous series. Category Education; Created using.

Homologous series, any of numerous groups of chemical compounds in each of which the difference between successive members is a simple structural unit. Such series are most common among organic compounds, the structural difference being a methylene group, as in the paraffin hydrocarbons, or alkanes; the normal primary alcohols, or 1-alkanols; and the normal carboxylic acids, or alkanoic acids.

Thieme E-Books & E-Journals. Abstract. In continuation of studies focusing on the transdermal delivery of antiretroviral (ARV) drugs, the skin permeation ability of synthesized homologous series of both oligomeric and polymeric ethylene glycol (PEG) carbonates of zidovudine (3'-azido-3'-deoxythymidine, AZT, CAS ) and stavudine (2',3'-dideoxy-2',3'-didehydrothymine, d4T, CAS Author: David D.

N'Da, Jaco C. Breytenbach, J. Wilhelmina Breytenbach. (). Antioxidant oligomeric proanthocyanidins from Cistus salvifolius. Natural Product Research: Vol. 20, No. 13, pp. Cited by:   to unlock the full series of AS & A-level Chemistry videos for the new OCR, AQA and Edexcel specification.

In today’s video we’ll discuss the concept of homologous series. Disclaimer. All content on this website, including dictionary, thesaurus, literature, geography, and other reference data is for informational purposes only. TOTAL AMOUNTS OF ANTIOXIDANTS IN HERBS AND SPICES. Herbal/traditional plant medicine is the most antioxidant-rich category in the present study and also the category with the largest variation between products.

Half of the products have antioxidant values above the 90th percentile of the complete food table and the mean and median values Cited by: 3. Start studying Homologous Series and Polymers. Learn vocabulary, terms, and more with flashcards, games, and other study tools.

In this study, a light phase oil was obtained by molecular distillation from cold-pressed grapefruit essential oil and GC-MS was used to identify its chemical composition.

The antimicrobial activity of the light phase oil was tested by filter paper diffusion method, and the anticancer activity was determined by the Cell Counting Kit-8 (CCK-8 Author: Weihui Deng, Ke Liu, Shan Cao, Jingyu Sun, Balian Zhong, Jiong Chun.

An abundant chloroplast protein is implicated in the assembly of the oligomeric enzyme ribulose bisphosphate carboxylase-oxygenase, which catalyses photosynthetic CO2 Cited by: \hō-¦ mä-lə-gəs\ n.A family of organic compounds that have identical functionality with each succeeding member having one more –CH 2 – group in its molecule than the preceding member.

An example is the series methanol (CH 3 OH), ethanol (CH 3 CH 2 OH), propanol (C 3. The word "series" implies that the members can be arranged in a single file and uniquely identified by an integer parameter.

Thus a collection of compounds with shared functional group(s) (such as alkyne) or chemical properties (such as aromatic hydrocarbons) may constitute a "chemical family" or "class of homologous compounds", but not.

A homologous series in organic chemistry is a group of organic compounds [compounds that contain carbon (C) atoms] that diverge from each other by one methylene (CH 2) group. For example, methane, ethane, and propane are part of a homologous series. Characteristics of a homologous series. Solid State 13C-NMR, Infrared, X-ray Powder Diffraction and Differential Thermal Studies of the Homologous Series of some Mono-valent Metal (Li, Na, K, Ag) n-alkanoates: A comparative study.

Peter N. Nelson, Henry A. Ellis, Nicole A. White, Spectrochimica Acta Part A, () – DOI: / Definition. An homologous series is a group of compounds with similar structural features that can be represented by a general formula whose members differ by one -CH 2 - unit.

You can think of an homologous series as a 'family' or group of compounds, whose chemical behaviour is very similar and whose physical properties show trends when ascending the members of the group (in terms of number. Homolytic Aromatic Substitution: International Series of Monographs on Organic Chemistry Paperback – Decem by G.

Williams (Author) See all 3 formats and editions Hide other formats and editions. Price New from Used from Kindle Author: G. Williams. haustive study of these compounds which Masquelier named pycnogenols, a term no longer used in the scientific community today except as a trademark for OPCs derived from French maritime pine bark.

Today they are known as oligomeric proanthocyanidin. Oligomer molecule: A molecule of intermediate relative molecular mass, the structure of which essentially comprises a small plurality of units derived, actually or conceptually, from molecules of lower relative molecular mass.

Note. A molecule is regarded as having an intermediate relative molecular mass if it has properties which do vary significantly with the removal of one or a few of the. A homologous series in organic chemistry is a group of organic compounds (compounds that contain C atoms) that differ from each other by one methylene (CH2) group.

For example, methane, ethane, and propane are part of a homologous series. The onl. The species M. piperita has significant antioxidant activity and p antioxidant activity is associated with the presence of linalool major compound (%).Gas chromatography-mass spectrometry (GC-MS) analysis revealed the major components in black cumin essential oils which were thymoquinone (%) followed by p-cymene (%), α -thujene (%), thymohydroquinone (%), and longifolene (%), whereas the oleoresins extracted in different solvents contain linoleic acid as a major by: