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C 2 H 5 OH Ethanol: 1.69 O x A y: Molecules with an O at one end H 2 O Water: 1.85 N x A y: Molecules with an N at one end NH 3: Ammonia: 1.42 Nonpolar A 2: Diatomic molecules of the same element O 2: Dioxygen: 0.0 C x A y: Most hydrocarbon compounds C 3 H 8: Propane: 0.083 C x A y: Hydrocarbon with center of inversion: C 4 H 10: Butane: 0.0
(However, PE only dissolves at temperatures well above 100 °C.) Poly(styrene) has a solubility parameter of 9.1 cal 1/2 cm −3/2, and thus ethyl acetate is likely to be a good solvent. Nylon 6,6 has a solubility parameter of 13.7 cal 1/2 cm −3/2, and ethanol is likely to be the best solvent of those tabulated. However, the latter is polar ...
Positive solvatochromism corresponds to a bathochromic shift (or red shift) with increasing solvent polarity. An example of positive solvatochromism is provided by 4,4'-bis(dimethylamino)fuchsone, which is orange in toluene, red in acetone. The main value of the concept of solvatochromism is the context it provides to predict colors of solutions.
Molecules with a polar surface area of greater than 140 angstroms squared (Å 2) tend to be poor at permeating cell membranes. [1] For molecules to penetrate the blood–brain barrier (and thus act on receptors in the central nervous system), a PSA less than 90 Å 2 is usually needed. [2] TPSA is a valuable tool in drug discovery and development.
In organic chemistry, umpolung (German: [ˈʔʊmˌpoːlʊŋ]) or polarity inversion is the chemical modification of a functional group with the aim of the reversal of polarity of that group. [1] [2] This modification allows secondary reactions of this functional group that would otherwise not be possible. [3]
The n-octanol-water partition coefficient, K ow is a partition coefficient for the two-phase system consisting of n-octanol and water. [1] K ow is also frequently referred to by the symbol P, especially in the English literature. It is also called n-octanol-water partition ratio. [2] [3] [4]
The Taft equation is a linear free energy relationship (LFER) used in physical organic chemistry in the study of reaction mechanisms and in the development of quantitative structure–activity relationships for organic compounds. It was developed by Robert W. Taft in 1952 [2] [3] [4] as a modification to the Hammett equation. [5]
The case for S N 2 reactions is quite different, as the lack of solvation on the nucleophile increases the rate of an S N 2 reaction. In either case (S N 1 or S N 2), the ability to either stabilize the transition state (S N 1) or destabilize the reactant starting material (S N 2) acts to decrease the ΔG ‡ activation and thereby increase the ...