Aliphatic compounds

The acyclic terpenes are discussed separately in Section 2.2. Some of the cycloaliphatic fragrance and flavor materials are structurally related to the cyclic terpenes and are, therefore, discussed in Section 2.4 after the cyclic terpenes. 

Chapter 4. Purification of Organic Chemicals — Aliphatic Compounds 

Dry acetal over Na to remove alcohols and H2O, and to polymerise aldehydes, then fractionally distil. Or, treat it with alkaline H2O2 at 40-45° to remove aldehydes, then saturate with NaCl, separate, dry with K2CO3 and distil it from Na [Vogel J Chem Soc 616 1948], [Beilstein 1IV 3103.] 

Distil the dimethyl acetal throngh a fractionating column and fraction boiling at 63.8°/751mm is collected. It forms an azeotrope with MeOH. Alternatively, purify it as for acetal above. It has been purified by GLC. [Beilstein 1IV 3103.] 

A-(2-Acetamido)-2-ammoethane ulfonic acid (ACES) [7365-82-4] M 182.2, m 220°(dec), pKg 1.5, PK2 6.9. RecrystalUse ACES from hot aqueoirs EtOH. [Perrin Dempsey Buffers for pH and Metal Ion Control Chapman Hall, London 1974, Beilstein 4 HI 1707.] 

7V-(2-Acetamido)iminodiacetic acid (ADA) [26239-55-4] M 190.2, m 219°(dec), pK 2.3, pKj 6.6. Dissolve ADA in water, add one equivalent of NaOH solution (to final pH of 8-9), then acidify with HCl to precipitate the free add. This is filtered off, washed with water and dried in vacuo. [Beilstein 4 TV 2441.] 

From the perspective of structural chemistry, the modes of bonding, coordination, and the bond parameters of a particular element in its allotropic modifications may be further extended to its compounds. Thus organic compounds can be conveniently divided into three families that originate from their prototypes aliphatic compounds from diamond, aromatic compounds from graphite, and fullerenic compounds from fullerenes. 

Aliphatic compounds comprise hydrocarbons and their derivatives in which the molecular skeletons consist of tetrahedral carbon atoms connected by C-C single bonds. These tetrahedral carbon atoms can be arranged as chains, rings, or finite frameworks, and often with an array of functional groups as substituents on various sites. The alkanes CMH2n+2 and their derivatives are typical examples of aliphatic compounds. 

Some frameworks of alicyclic compounds are derived from fragments of diamond, as shown in Fig. 14.2.1. In these molecules, all six-membered carbon rings have the chair conformation. Diamantane C14H20 is also named 

Some frameworks of alicyclic compounds as fragments of diamond. 

Lignified tissues give color reactions with several alcohols and ketones in the presence of small amounts of mineral acids (Brauns 1952). For example, methanol- or acetone-hydrochloric acid forms a red color on contact with spruce wood amyl alcohol-sulfuric acid gives a blue color and methylheptenone, (CH3)2C=CHCH2CH2COCH3, a purple-red color when applied to spruce wood. 

Thiols are oxidized by NH2CI to disulfides (Ingols et al., 1953). Monochloramine reacts with aldehydes (although in many cases the reaction is slow Hauser and Hauser, 1930 Conyers and Scully, 1993) to form N-chloroimines (R-CH = NC1) which then undergo further reactions (elimination of HCl to the nitrile hydrolysis to aldehydes polymerization etc.) 

From S, D. Faust and J. V. Hunter, Eds. Principles and Applications of Water Chemistry, John Wiley Sons, 1967. Reprinted by permission. 

The detergent additive nitrilotriacetic acid (NTA, 45), although practically inert to chlorination under environmentally realistic conditions, does react at pH 11 with 

7 M NaOCl (essentially, undiluted laundry bleach) to give a 40% yield of the side-chain cleavage product, N-formyliminodiacetic acid (46 Spanggord and Tyson, 1979). 

N-Chlorocompounds are themselves capable of reacting with some organic compounds to produce oxidation or chlorination products. 4-N-Chlorocytosine (47), for example, reacts with phenylalanine to give a low yield of phenylacetaldehyde (Patton et ah, 1972). Presumably, the N-chloro amino acid is formed as an intermediate by direct chlorine atom transfer between 47 and phenylalanine. 

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Certain aliphatic compounds are oxidised by concentrated nitric acid, the carbon atoms being split off in pairs, with the formation of oxalic acid. This disruptive oxidation is shown by many carbohydrates, e.g., cane sugar, where the chains of secondary alcohol groups, -CH(OH)-CH(OH)-CH(OH)CH(OH)-, present in the molecule break down particularly readily to give oxalic acid. 

It should be noted that aliphatic compounds (except the paraffins) are usually oxidised by concentrated nitric acid, whereas aromatic compounds (including the hydrocarbons) are usually nitrated by the concentrated acid (in the presence of sulphuric acid) and oxidised by the dilute acid. As an example of the latter, benzaldehyde, CjHsCHO, when treated with concentrated nitric acid gives ffi-nitrobenzaldehyde, N02CgH4CH0, but with dilute nitric acid gives benzoic acid, CgHgCOOH. 

The iodine atom in iodobenzene (unlike that in the corresponding aliphatic compounds) is very resistant to the action of alkalis, potassium cyanide, silver nitrite, etc. This firm attachment of the iodine atom to the benzene ring is typical of aromatic halides generally, although in suitably substituted nitio-compounds, such as chloro-2,4-dinitrobenzene, the halogen atom does possess an increased reactivity (p. 262). 

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