Esters

5 Key excerpts on "Esters"

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  Hamilton and Hardy's Industrial Toxicology

  • Raymond D. Harbison, Marie M. Bourgeois, Giffe T. Johnson(Authors)
  • 2015(Publication Date)
  • Wiley

    (Publisher)

  57 Esters Raymond D. Harbison and C. Clifford Conaway

  Esters are compounds that result from the reaction of an alcohol or phenol with acids or derivatives of acids. Almost all the aliphatic Esters are prepared by the reaction between carboxylic acids and alcohols. The subclasses of Esters presented in this chapter include the aliphatic Esters, halogenated acid Esters, alkyl Esters of sulfuric acid, important phosphate Esters, nitrate Esters, and Esters of phthalic acid. Some Esters, such as aliphatics Esters, may present human health hazards (USEPA, 2007), if exposure occurs via the respiratory or dermal routes.

  Many organic Esters are used extensively in the plastic industry, either as resins or as plasticizers, and as solvents for lacquers. The group of Esters, including succinate, adipate, azelate, sebacate, citrate, and phthalate is generally used as plasticizers. Esters of inorganic acids, such as Esters of sulfuric acid and phosphate Esters, may have prominent corrosive or pharmacological properties. See Table 57.1

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  Chemistry for Today

  General, Organic, and Biochemistry

  • Spencer Seager, Michael Slabaugh, Maren Hansen, , Spencer Seager, Spencer Seager, Michael Slabaugh, Maren Hansen(Authors)
  • 2021(Publication Date)
  • Cengage Learning EMEA

    (Publisher)

  This same buffer is used in medicines and in human blood that is used for transfusions. In blood, it also functions as an anticoagulant. 15.5 Carboxylic Esters Learning Objective 6 Recognize and write key reactions for ester formation. A very important reaction occurs when carboxylic acids are heated with alcohols or phenols in the presence of an acid catalyst. A molecule of water splits out and a carboxylic ester is formed. C carboxylic acid 1 H 2 O carboxylic ester O 1 OH C O R R R9 H H 1 , heat General reaction: O alcohol or phenol R9 O (15.8) As before, R9 indicates that the two R groups can be the same or different. The process of ester formation is called esterification, and the carbonyl carbon–oxygen single bond of the ester group is called the ester linkage: C O O C ester group ester linkage The ester functional group is a key structural feature in fats, oils, and other lipids (see Chapter 18). Also widely found in fruits and flowers, many Esters are very fragrant and represent some of nature’s most pleasant odors (see Figure 15.10). Because of this char- acteristic, Esters are commonly used as flavoring agents in foods and as scents in personal products (see Figure 15.11). carboxylic ester C O OR A compound with the functional group. esterification The process of forming an ester. ester linkage The carbonyl carbon–oxygen single bond of the ester group. FIGURE 15.10 Esters are partially responsible for the fragrance of oranges, pears, bananas, pineapples, and strawberries. © Mark Slabaugh FIGURE 15.11 Esters are common in familiar flavorings. (a) Grape flavoring, the ester methyl anthranilate, is added to children's Tylenol to make it tastier. (b) Methyl salicylate, present in wintergreen, has analgesic and anti-inflammatory properties as well as a unique flavor. a b Keith Homan/Shutterstock.com Gabriela Beres/Shutterstock.com Copyright 2022 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part.

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  Surfactants in Personal Care Products and Decorative Cosmetics

  • Linda D. Rhein, Mitchell Schlossman, Anthony O'Lenick, P. Somasundaran, Linda D. Rhein, Mitchell Schlossman, Anthony O'Lenick, P. Somasundaran(Authors)
  • 2006(Publication Date)
  • CRC Press

    (Publisher)

  The Esters having fewer carbon atoms for the most part do not have the requisite oiliness. The ester, unlike the hydrocarbon, contains a polar group. That polar group is made up of a carbonyl group and an oxygen group, commonly referred to as an ester linkage. The nature of this polar group alters the properties vis-à-vis hydrocarbons. As will become evident, there are a number of ester types, each of which results in a variety of solubilities, polarities, and viscosities. Each will have a function in the preparation of stable pigment dispersions. 21.2.1 S IMPLE E STERS Simple Esters are made by the reaction of a fatty acid and a fatty alcohol. The reaction is as follows: O O ∂∂ ∂∂ R ´ OH + R’C ´ OH R’ ´ C ´ OR + H 2 O The reaction is conducted at high temperature (typically 180 to 240 ° C), and the water generated is removed under vacuum. Since the reaction is done at high temperature, the introduction of air during processing will result in significant darkening. Therefore, reactions are often carried out under a nitrogen blanket. 21.2.1.1 Fatty Acid Nomenclature A shorthand nomenclature for the fatty components used has been adopted. 2 The convention is C-18:1, which means 18 carbon atoms with 1 double bond between carbon atoms. This would commonly be called an oleic acid. This double bond occurs predominantly between the 9th and 10th carbon atoms from the carboxyl acid group. Fatty Esters in the cosmetic business use common, rather than International Union of Pure and Applied Chemistry (IUPAC), names (Table 21.1). The ester is named by taking the name of the fatty acid and changing the ending to ate and preceding it with the name of the alcohol’s alkyl group. O R—C—OR ′  → 

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  Synthetics, Mineral Oils, and Bio-Based Lubricants

  Chemistry and Technology

  • Leslie R. Rudnick(Author)
  • 2020(Publication Date)
  • CRC Press

    (Publisher)

  3

  Esters

  Stephen Boyde Contents 3.1 Introduction and Historical Development 3.2 Chemistry 3.2.1 Ester Structure 3.2.2 Raw Materials 3.2.2.1 General 3.2.2.2 Renewability 3.2.2.3 Acids 3.2.2.4 Alcohols 3.2.3 Ester Types 3.2.3.1 MonoEsters 3.2.3.2 DiEsters 3.2.3.3 Neopentyl Polyol Esters 3.2.3.4 Complex Esters 3.2.3.5 Other Esters 3.2.4 Synthesis and Production 3.2.4.1 Manufacturing Process 3.2.4.2 Specifications 3.3 Properties and Performance Characteristics 3.3.1 Structure–Property Relationships 3.3.1.1 Viscosity 3.3.1.2 Volatility 3.3.1.3 Flow Properties (Viscosity Index and Pour Point) 3.3.1.4 Lubricity 3.3.1.5 Polarity and Material Compatibility 3.3.2 Stability 3.3.2.1 Thermal and Oxidative Stability 3.3.2.2 Hydrolytic Stability 3.3.2.3 Shear Stability 3.3.3 Safety, Health, and Environmental Properties 3.3.3.1 Biodegradability 3.3.3.2 Toxicity and Ecotoxicity 3.3.3.3 Recycling and Reuse 3.3.3.4 Renewability 3.4 Application Areas 3.4.1 Engine Oils 3.4.2 Automotive Gear 3.4.3 Two Stroke 3.4.4 Aviation Turbine Oils 3.4.5 Hydraulic Fluids 3.4.5.1 Biodegradable Hydraulic Fluids 3.4.5.2 Fire Resistant 3.4.6 Air Compressor 3.4.7 Refrigeration Compressor 3.4.8 High-Temperature Chain Oils 3.4.9 Metalworking Fluids 3.4.10 Greases 3.4.11 Drilling Muds 3.4.12 Transformer/Dielectric Fluids 3.5 Marketing and Economics 3.5.1 Manufacturers 3.5.2 Markets 3.6 Outlook Acknowledgments References

  3.1 Introduction and Historical Development

  The ester functional group provides a versatile means of assembling complex organic structures from simple acid and alcohol building blocks. Ester products are ubiquitous in both synthetic and natural product chemistry. This chapter focuses on synthetic organic ester basefluids, that is, viscous, water-immiscible liquids, containing only C, H, and O, manufactured by esterification processes, and used as major components of formulations intended to reduce friction and wear in machinery.

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  Biochemistry

  An Organic Chemistry Approach

  • Michael B. Smith(Author)
  • 2020(Publication Date)
  • CRC Press

    (Publisher)

  8  Lipids

  Lipids are organic compounds such as fatty acids or natural oils, waxes, and steroids that are insoluble in water but soluble in organic solvents. Fatty acids are components of triglycerides and the hydrolysis of triglycerides is important for energy conversion in living systems. Lipids are important for the formation of lipid bilayers and the chemistry of Esters is important to the discussion of lipids.

  8.1 Carboxylic Acids and Esters

  An important functional group has a carbon atom (alkyl group) attached to a carbonyl (C=O) functional group, but a hydroxyl (OH) group is also attached to the carbonyl carbon. This unit is known as a carboxyl group , also written as —COOH or —CO2 H, and it is the major structural feature of the class of organic molecules known as carboxylic acids . This structural arrangement is shown in the box on ethanoic acid (the common name is acetic acid; Figure 8.1 ). The polarization induced by the electronegative carboxyl oxygen makes the carboxyl carbon atom positive, which leads to the oxygen of the O—H unit being negatively polarized, and the hydrogen positively polarize; i.e., the proton is acidic. The O—H proton of a carboxylic acid is much stronger (pK a 1–5) than the O—H proton of an alcohol (pK a 16–18).

  FIGURE 8.1 Ethanoic acid.

  Fatty acids are long-chain carboxylic acids, and there are several classes. Certain terminology can be used, particularly for fatty acids that are found in nature. The carboxylic acid end is polar, associated with water solubility, and is labeled the delta (Δ) end of the fatty acid. The methyl end is associated with being nonpolar, more soluble in oils, and is labeled the omega (Ω) end of the fatty acid.

  The so-called essential fatty acids are those required in the diet because they cannot be synthesized by human cells. Common naturally occurring fatty acids include the C14 acid (myristic acid), the C16 acid (palmitic acid), the C18 acid (stearic acid), and the C20

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