Physical Properties of Amines

4 Key excerpts on "Physical Properties of Amines"

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  eBook - PDF

  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)

  ● Aromatic amines are named as derivatives of aniline. 16.3 Physical Properties of Amines Learning Objective: Can you discuss how hydrogen bonding influences the Physical Properties of Amines? ● Primary and secondary amines have boiling points slightly lower than those of corresponding alcohols. ● Tertiary amines have boiling points similar to those of alkanes. ● Low-molecular-weight amines are water-soluble. 16.4 Chemical Properties of Amines Learning Objective: Can you recognize and write key reactions for amines? ● Amines are weak bases. ● They react with water to liberate hydroxide ions. ● They react with acids to form salts. ● Amines react with acid chlorides and acid anhydrides to form amides. 16.5 Amines as Neurotransmitters Learning Objective: Can you name amines used as neurotransmitters? ● Neurotransmitters are the chemical messengers of the nervous system. ● They carry nerve impulses from one nerve cell (neuron) to another. ● The most important neurotransmitters are acetylcholine and three other amines: norepinephrine, dopamine, and serotonin. 16.6 Other Biologically Important Amines Learning Objective: Can you give uses for specific biological amines? ● Four neurotransmitters are acetylcholine, norepinephrine, do- pamine, and serotonin. ● Epinephrine is also known as the fight-or-flight hormone. ● The amphetamines have structures similar to that of epinephrine. ● Alkaloids are nitrogen-containing compounds isolated from plants. ● They exhibit a variety of physiological effects on the body. ● Examples of alkaloids include nicotine, caffeine, quinine, at- ropine, morphine, and codeine. 16.7 The Nomenclature of Amides Learning Objective: Can you assign IUPAC names for amides? ● Amides are named by changing the -ic acid or -oic acid end- ing of the carboxylic acid portion of the compound to -amide. ● Groups attached to the nitrogen of the amide are denoted by an italic capital N that precedes the name of the attached group.

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  Organic and Biological Chemistry

  • H. Stephen Stoker(Author)
  • 2015(Publication Date)
  • Cengage Learning EMEA

    (Publisher)

  6-5 Physical Properties of Amines 207 amines; carbon atom partitioning can be two ethyl groups, a propyl group and a methyl group, or an isopropyl group and a methyl group. and CH 3 CH 2 O CH 2 O NH CH 3 O O N -Ethylethanamine CH 3 CH 2 O NH O CH 2 CH 3 O O N -Methyl-1-propanamine and CH 3 CH 3 O CH NH O CH 3 O A N -Methyl-2-propanamine 1. In which of the following pairs of amines are the two members of the pair constitutional isomers? a. CH 2 O CH 2 O N CH 2 O CH 3 O NH 2 H 2 and CH 3 O b. CH 2 O CH O CH 3 and CH 2 O CH O CH 3 CH 3 O CH 3 O NH 2 A NH 2 A c. CH O CH 3 CH 3 O NH 2 A CH 2 O CH 2 and CH 3 O NH 2 A d. no correct response 2. In which of the following pairs of amines are the two members of the pair not constitu-tional isomers? a. CH 3 O NH O CH 2 O CH 2 O CH 3 and CH 3 O CH 2 O NH O CH 2 O CH 3 b. CH 3 O NH O CH 2 O CH 2 O CH 3 and CH 3 O CH 2 O CH 2 O CH 2 O NH 2 c. CH 3 A CH 3 O CH 2 O NH O CH 2 O CH 3 and CH 3 O CH 2 O N O CH 3 d. no correct response Section 6-4 Quick Quiz Answers: 1. c; 2. d 6-5 Physical Properties of Amines L E A R N I N G F O C U S Be familiar with general physical properties for amines and how hydrogen bonding relates to these properties. The methylamines (mono-, di-, and tri-) and ethylamine are gases at room tempera-ture and have ammonia-like odors. Most other amines are liquids (Figure 6-3), and many have odors resembling that of raw fish. A few amines, particularly diamines, have strong, disagreeable odors. The foul odor arising from dead fish and decaying flesh is due to amines released by the bacterial decomposition of protein. Two of these “odoriferous” compounds are the diamines putrescine and cadaverine. H N 2 ¬ (CH ) 2 5 ¬ NH 2 H 2 N ¬ (CH ) 2 4 ¬ NH 2 Putrescine (1,4-butanediamine) Cadaverine (1,5-pentanediamine) The simpler amines are irritating to the skin, eyes, and mucous membranes and are toxic by ingestion.

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  Introduction to General, Organic, and Biochemistry

  • Morris Hein, Scott Pattison, Susan Arena, Leo R. Best(Authors)
  • 2014(Publication Date)
  • Wiley

    (Publisher)

  NHCH 3 CH 3 CH 2 CH 2 N-methyl-1-propanamine (N-methylpropylamine) More Practice? Try Paired Exercises 25–30. 25.7 CHEMICAL PROPERTIES OF AMINES Relate the basic properties of amines to their reactions with water and acids; understand amines are needed to form amides. Alkaline Properties of Amines In many respects, amines resemble ammonia in their reactions. Thus, amines are bases and, like ammonia, produce OH - ions in water: H OH NH 4 � � OH � ammonium ion hydroxide ion NH 3 ammonia molecule � ∆ KEY TERM amines are bases LEARNING OBJECTIVES A Brønsted–Lowry base is a proton (H + ) acceptor. 25.7 • Chemical Properties of Amines 655 Methylamine and aniline react in the same manner: H OH CH 3 NH 3 � OH � methylammonium ion hydroxide ion CH 3 NH 2 methylamine molecule � NH 2 H OH � � OH � hydroxide ion NH 3 � anilinium ion aniline molecule � ∆ ∆ The ions formed are substituted ammonium ions. They are named by replacing the -amine ending by -ammonium and, for the aromatic amines, by replacing the -aniline name by -anilinium. CH 3 o-methylanilinium ion NH 3 N-methylanilinium ion CH 3 NH 2 CH 3 NH 2 CH 3 dimethylammonium ion    Like ammonia, amines are weak bases. Methylamine is a slightly stronger base than am- monia, and aniline is considerably weaker than ammonia. The pH values for 0.1 M solutions are methylamine, 11.8; ammonia, 11.1; and aniline, 8.8. Because amine groups form substituted ammonium ions under physiological conditions, they provide the positive charge for biological molecules. For example, neurotransmitters are often positively charged.

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  eBook - ePub

  Ullmann's Fine Chemicals

  • (Author)
  • 2014(Publication Date)
  • Wiley-VCH

    (Publisher)

  N -alkyl-1,3-propanediamines. Of commercial importance are fatty amine mixtures, such as coco amine, tallow amine, hydrogenated tallow amine, oleylamine, and soya amine, which are derived from naturally occurring fatty acids. More recently, alkylamines of similar structure were produced from synthetic feedstocks such as olefins or paraffins, and these also are called fatty amines (β-amines, branched chain amines, aminoalkanols). Only partly covered are fatty amine ethoxylates, fatty alkyl quaternary ammonium salts, alkyl betaines and fatty amine oxides, although all of these are fatty amine derivatives.

  7.1. Properties

  Physical Properties. Table 2 lists typical compositions of fatty amine mixtures. The properties of these can be varied to some extent by blending chain lengths with the desired physical characteristics. Fatty acids are also available in fractionated form and thus narrower ranges of fatty amines may be produced.

  Table 2 Mixture composition of primary fatty amines (mass fraction in %) [157]

  Solubilities of selected fatty amines in polar and nonpolar organic solvents are given in Table 3 . Only the short-chain fatty amines with 8 – 10 °C atoms per alkyl chain are of limited solubility in water.

  Table 3 Solubility (g per 100 mL at 30 °C) of fatty amines in organic solvents [158]

  2-Propanol	Hexane
  Primary amines
  Dodecylamine	∞	∞
  Tetradecylamine	458	216
  Hexadecylamine	169	64.8
  Octadecylamine	86	27.9
  Secondary amines
  Dioctylamine	∞	∞
  Didodecylamine	55	27.5
  Dioctadecylamine	1.2 (50 °C)	2.1 (40 °C)
  Tertiary amines
  Trioctylamine	∞	∞
  Tridodecylamine	23.9	∞
  Trioctadecylamine		36.4

  Vapor Pressures at ambient temperature are generally very low and decrease from 26.5 Pa for dodecylamine to 2.7 × 10−2 Pa (0.27 × 10−3 mbar) for eicosylamine. Some physical properties of pure compounds and commercial mixtures are given in Table 4 .

  Table 4 Physical properties of fatty amines [159–162]

  The oscillation of melting points between the series of odd-chain and even-chain homologues is shown in Figure 2 . This effect disappears in derivatives of primary fatty amines.

  Figure 2. Melting points of primary amines

  Almost all amines derived from natural sources have an even number of carbon atoms. Diamines and 2-(alkylimino)diethanols [N ,N

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