Morpholine: physical properties

Due to the physical properties of the morpholines and the need to coformulate with other, mostly solid a.i s, suspoemulsions were again the formulation form of choice found in many sales products. 

PHYSICAL PROPERTIES colorless crystals or white to off-white powder odorless or slight, aromatic odor insoluble in water practically insoluble in dilute acids and alkalies soluble in acetone, benzene, ether, carbon tetrachloride, kerosene, morpholine, tetralin, and tributyl phosphate freely soluble in pyridine and dioxane solubility in organic solvents increases with elevated temperatures MP (108.5-109°C, 227-228°F) BP (260°C, 500°F) DN (1.5 g/cm ) SG (0.99 at 20°C) VP (1.5 x 10 mmHg at 20°C) UV MAX (236nm). 

Table 10.6 lists the physical properties of six amide-type solvents, two cyclic morpholines (amine-ether structures) and the low molecular weight... 

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). 

As the result of our kinetic evidence, we had to propose a mechanism (Scheme 2) for the process of RNA cleavage by imidazole buffer, and other buffers such as morpholine, in which the first function of the BIP" is to protonate the phosphate group. We have proposed [2] that the enzyme ribonuclease A uses a related mechanism (Scheme 3)— but simultaneous instead of sequential—and cited some physical and calculational evidence in support of this proposal. We have used the evidence from this mechanistic work to redesign a catalyst that imitates some aspects of the enzyme mechanism. However, we were also forced to think about the properties of the isomeric 2, 5 -linked nucleic acids whose formation was a key piece of evidence in the mechanistic studies. We will first describe work fliat addresses this question. 

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