Handbook of Antioxidants

George Wypych

• Publisher: ChemTec Publishing
• Year: 2020
• eBook ISBN: 9781927885604
• Topic: Physical Sciences
• Subtopic: Physical & Theoretical Chemistry

Handbook of Antioxidants provides a wealth of information on the mechanics, practical effects and applications of a wide range of antioxidants. The book starts by introducing the general concepts relating to antioxidants and their application, then segues into a discussion on existing natural and synthetic antioxidants, characterizing their general properties and application. Formation and action of oxidizing species in living organisms, ambient air, industrial environments, and chemical reactions are covered next. Subsequent chapters cover the theories and mechanisms of stabilization, performance indicators, antioxidant selection, degradation and stabilization of different polymers and rubbers, specific effects on other components of formulation, and analytical methods. This book is an excellent companion to the Databook of Antioxidants which has also been published recently. Both books supplement each other without repeating the same information – one contains data another theory, mechanisms of action, practical effects and implications of application.- Provides theory, mechanisms of action, practical effects and implications of application for an array of antioxidants- Looks at different aspects of phenomena occurring when materials are exposed to ambient air which contains oxygen, ozone, singlet oxygen, and other oxidizing species (radicals)- Covers natural and synthetic antioxidants, their stability, performance indicators, degradation and stabilization mechanics, and more

1

INTRODUCTION

The two most popular definitions of oxidation processes are based on the description of chemical reaction which leads to the formation of oxidation product (a combination of the substance being oxidized and oxygen) or in broader terms a reaction in which one atom loses electron but increases its valence.

There are several terms that are almost synonymous with oxidation, such as combustion, rusting, nitrification, calcination, converting food to energy, or breathing. Oxidation has a negative connotation when materials or leaving cells are being damaged in the process and positive meaning when we produce new compounds, convert the energy of molecular bonds to heat, passivate the surface of metals, or simply breath air. From this subjective division comes prevention or its lack. For all these negative connotations, we develop systems preventing or delaying oxidation. The additives which take the impact of oxidation reaction are called antioxidants, and they are the primary subject of this book.

The action of antioxidants is more complicated than just a simple replacement of material targeted by oxygen. Oxidation is a chain reaction involving free radicals and hydroperoxide intermediates. Therefore, antioxidants must also act by reacting and decomposing free radicals and hydroperoxide intermediate species.

Because of widespread applications, various groups of chemicals (in total 32 groups of additives) are involved in antioxidation, including acids and their esters, algae, amines, anthocyanidines, ascorbates, benzofuranones, benzoimidazoles, benzoquinones, biopolyphenols, curcumin, coumarin, enzymes, extracts, flavonoids, graphene, hydrazide metal deactivators, hydroquinidines, hydroquinones, hydroxylamines, isoflavones, lignanamides, liposomes, mitochondria-targeted antioxidants, oil derivatives, peptides, phenolics, phosphites, phospholipides, polyphenols, stilbene derivatives, sulfur-containing compounds, terpenoids, and tocopherols. Chapter 2 contains a brief discussion of the general properties of these groups of antioxidants with emphasis on chemical composition, physical-chemical properties, UV absorption, forms, application to polymers and final products, and concentrations used. This chapter contains only a summary of the properties of groups of antioxidants involved. The details on different representatives of the groups are included in the companion book – Databook of Antioxidants, which brings information on individual products. The selection of antioxidants is critical because, in modern applications, synthetic antioxidants are gradually being replaced by the products obtained from renewable resources, mostly of plant origin. This conversion in the area of cosmetics, medicine, pharmacy, food additives, and food protection is very advanced. In polymer processing, the application of natural antioxidants is still on the developmental stage but essential to know for future replacement options and performance.

Chapter 3 contains information on the physics and chemistry of oxidation and antioxidation, including the influence of UV radiation. In this chapter, peculiarities of oxidation and its prevention by antioxidants are discussed for different groups of antioxidants. In total, 25 groups of antioxidants are discussed in separate sections of this chapter. The focus of the evaluation of research findings is on the mechanism of action of antioxidants, their stability, and eventual methods of its improvement.

A separate discussion of the effects of oxidation and photooxidation on living cells is included in Chapter 4. In the introduction, the differences and similarities between the behavior of polymers and livings things and their use of antioxidants are briefly outlined. The opening is followed by separate sections discussing oxidation phenomena in microorganisms, plants, fish, animals, and humans.

Chapter 5 constitutes the technological part of the book, which includes the analysis of progress and applications of antioxidants in different polymers and rubbers. In total, 66 polymers are discussed in separate sections of this chapter. The main subjects of this discussion include mechanisms of degradation and its prevention by antioxidants. Selection of the most suitable antioxidants and methods of their use constitutes one of the main subjects of discussion. This part of the book heavily relies on patent literature in addition to the scientific findings. The emphasis is given to the most recent applications rather than a historical review of applications.

2

TYPICAL GROUPS OF ANTIOXIDANTS

In this chapter, the information on typical groups of antioxidants is presented in the form of tables containing information on the range of properties (general, physical, chemical, health, ecological, and uses). The presented data are based on information obtained from manufacturers of several hundred commercial additives and data found in research papers.

2.1 ACIDS AND THEIR ESTER

GENERAL
Names: coumaric acid, ellagic acid, ferulic acid, gallic acid, isochlorogenic acid, kojic acid, lipoic acid, nordihydroguaiaretic acid, propyl galate, salvianolic acid, sulfonic acid
CAS #: 62-46-4, 121-79-9, 149-91-7, 476-66-4, 500-38-9, 501-30-4, 501-98-4, 1135-24-6, 2450-53-5, 30931-67-0, 121521-90-2
Molecular weight: 142-718	Biobased: Y/N	Mixture: N
PHYSICAL
Color: white, off-white, beige, brown, cream, yellow		pKa: 3.52-9.56
Boiling point, °C: 312	Freezing point, °C: 45-260	State: solid
Odor: odorless, balsamic, faint	Specific gravity: 1.29-1.69
Solubility: acetone, DMF, DMSO, ethanol, ethyl acetate, chloroform, glycerol, glycol, methanol, pyridine
Max. UV absorbanc...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Chapter 1: INTRODUCTION
• Chapter 2: TYPICAL GROUPS OF ANTIOXIDANTS
• Chapter 3: PHYSICS AND CHEMISTRY OF OXIDATION AND ANTIOXIDANTS
• Chapter 4: OXIDATION IN LIVING CELLS
• Chapter 5: PREVENTION OF OXIDATION OF SELECTED POLYMERS AND RUBBERS
• INDEX