Secondary amines physical properties

When additional substituents ate bonded to other ahcycHc carbons, geometric isomers result. Table 2 fists primary (1°), secondary (2°), and tertiary (3°) amine derivatives of cyclohexane and includes CAS Registry Numbers for cis and trans isomers of the 2-, 3-, and 4-methylcyclohexylamines in addition to identification of the isomer mixtures usually sold commercially. For the 1,2- and 1,3-isomers, the racemic mixture of optical isomers is specified ultimate identification by CAS Registry Number is fisted for the (+) and (—) enantiomers of /n t-2-methylcyclohexylamine. The 1,4-isomer has a plane of symmetry and hence no chiral centers and no stereoisomers. The methylcyclohexylamine geometric isomers have different physical properties and are interconvertible by dehydrogenation—hydrogenation through the imine. 

Amines are polar compounds. Primary and secondary amines can form hydrogen bonds, but tertiary amines cannot. Table 1.8 lists some common physical properties of amines. 

This work describes the application of a previous study which dealt primarily with organic synthesis and physical properties of reaction products of pure fatty acids with BETA. Derivatives to amplify the previous study were prepared from various industrial fatty materials. The reaction product, from 1 mole diethylenetriamine (BETA) with 2 moles fatty acid, was thought to be the primary amine, RC0N(CH2CH2NH2) CH2CH2NHCOR, rather than the secondary amine, as cited in the literature. The amine was readily dehydrated to the imidazoline,... 

Four types of organic amines exist, as shown in Table 4.8 primary amines RNHj, secondary R2NH2, tertiary RsNH, and quaternary R4N (Appendix D). The hydrocarbon chain R is usually of length Cg-Cu, commonly a straight aliphatic chain, but branched chains and aromatic parts also occur. In general the amines extract metal complexes in the order tertiary > secondary > primary. Only long-chain tertiary and—to a smaller extent—quarternary amines are used in industrial extraction, because of their suitable physical properties trioctylam-ine (TOA, 8 carbons per chain) and trilauryl amine (TLA, 12 carbons per chain) are the most frequently used. For simplicity we abbreviate all amines by RN, and their salts by RNH L . 

The physical properties of amines depend in an important way on the extent of substitution at nitrogen. Thus primary amines, RNH2, and secondary amines, R2NH, are less volatile than hydrocarbons of similar size, weight, and shape, as the following examples show ... 

One of the most commonly used class of derivatization agents for diasteromer formation are isothiocyanates and isocyanates. Enantiomers of /3-blockers, amphetamine, epinephrine, methamphetamine, and mexiletine have been resolved after derivatization with these agents. Isothiocyanates produce thiourea derivatives upon reaction with primary and secondary amines. Thiourea derivatives also provide a strong UV absorbance for the detection of enantiomers lacking a strong UV chromophore. Isocyanates produce ureas when reacted with amines. The physical properties of these ureas are similar to thiourea derivatives. Isocyanates will also react with alcohols to yield carbamates. 

Amines exhibit dipole-dipole interactions because of the polar C-N and N—H bonds. Primary and secondary amines are also capable of intermolecular hydrogen bonding, because they contain N—H bonds. Because nitrogen is less electronegative than oxygen, however, intermolecular hydrogen bonds between N and H are weaker than those between O and H. How these factors affect the physical properties of amines is summarized in Table 25.1. 

The existence of such an inner salt is well established by the physical properties of many amino acids and by the chemical reactions of the higher alkylated amino derivatives formed by converting the primary amine group into secondary and tertiary alkyl amine groups. 

The maleimide group can undergo a variety of chemical reactions, including polymerizations induced by free radicals or anions. Nucleophiles such as primary and secondary amines , as well as thiophenoxides , can react via a classical Michael-type addition mechanism . The maleimide group can also act as a very reactive dienophile and is thns nsed in a variety of Diels-Alder reactions . By varying the natnre of the linkages between the maleimide rings, the physical properties of the bis(maleimide) can be altered. 

Physical properties of these poly[2] catenaries have been explored in expectation of unique properties based on the catenane structure [239, 246]. While various interesting physical properties were found in polyrotaxane, no characteristic property has been reported in [2]catenanes so far. Although poly[2]catenane has highly mobile moiety due to the mechanical bond, it has been suggested that the connection between [2]catenane subunit restricted the mobility in motion of [2]catenane. Further, intramolecular interaction in [2]catenane subunit may decrease its mobility. Secondary amide-based [2]catenanes can easily be prepared from commercially available compounds. Takata et al. found that the borane-reduction of the [2]catenanes afforded good yields of the amine-based [2]catenanes that can be useful for polymer synthesis [247, 148] (Scheme 51). Although the origi-... 

A number of antioxidants were examined for solubility in the monomer, effect upon the photoinitiator, UV stability, effect upon physical properties of the cured coating and their effectiveness as stabilizers. The addition of hydrogen donors, HD-2 or HD-3, or a hindered amine light stabilizer, HALS-1, improves the stability of a cured epoxy acrylate system with a minimal change in the physical properties of the resin. DSC and oxygen absorption measurements show that the secondary hindered amine, HALS-1, imparts the best stability to the resin. 

Possible dispositions of the secondary amine hydrogen atoms in a coordinated macrocyclic tetraamine. Each isomer, formed only on coordination, exhibits slightly different physical properties. 

Saturated heterocycles containing five or more atoms have physical and chemical properties typical of acyclic compounds that contain the same heteroatom. For example, pyrrolidine, piperidine, and morpholine are typical secondary amines, and A-methylpyrrolidine and quinuclidine are typical tertiary amines. The conjugate acids of these amines have pK values expected for ammonium ions. We have seen that the basicity of amines allows them to be easily separated from other organic compounds (Chapter 1, Problems 70 and 71). 

Dimethylamine, (CH3)2NH, is a representative of the class of secondary amines. It resembles closely methylamine in physical and chemical properties. It is a gas, with a strong, fishy odor, and can be condensed to a liquid which boils at 7.2° it is found in herring brine. It is formed when methyl iodide is heated with ammonia. Methylamine is first formed and then converted into dimethylamine. The first reaction consists in the addition of the halide and ammonia —... 

Polyalkylenimines (PAIs) are a class of cationic polymers that have a generalised structure with secondary or tertiary amines in the main separated by all lene spacers, as shown in Scheme 2.1. Due to the presence of the nucleophilic amine groups in the polymer backbone, their synthesis is more complicated compared to simpler vinyl based polymers. This chapter will focus on the synthesis of the PAIs, their physical properties and a short review of applications, focusing on gene delivery. This chapter will only cover PAI homopolymers and excludes the convoluted area of block copolymers, as this is worth a full review by itself. 

Table 10.5 lists the physical properties of the aromatic-type pyridine and the three isomeric methyl derivatives (picolines) as well as the 2-ethyl and 4-ethyl pyridine derivatives. Complete hydrogenation of the pyridine ring yields the cyclic secondary amine, piperidine, which is also listed in Table 10.5. The pyridine derivatives are medium boiling liquids with flash points in the range of 37-134°F. The substitution of a nitrogen atom for a carbon atom in the benzene ring gives the pyridine derivative with much higher Hansen polarity and hydrogen bonding values (5 = 8.8 and 5 , = 5.9) than the benzene molecule (6 = 0 and 6 = 2.0).

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