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Dimethylamine is a weak base and the pKa of the ammonium CH 3-NH + 2-CH 3 is 10.73, a value above methylamine (10.64) and trimethylamine (9.79). Dimethylamine reacts with acids to form salts, such as dimethylamine hydrochloride, an odorless white solid with a melting point of 171.5 °C.
With a pK a of 12.34 [4] for its conjugate acid in aqueous solution, 1,8-bis(dimethylamino)naphthalene is one of the strongest organic bases. However, it only absorbs protons slowly—hence the trade name. The high basicity is attributed to the relief of strain upon protonation and/or the strong interaction between the nitrogen lone pairs. [3]
The higher the proton affinity, the stronger the base and the weaker the conjugate acid in the gas phase.The (reportedly) strongest known base is the ortho-diethynylbenzene dianion (E pa = 1843 kJ/mol), [3] followed by the methanide anion (E pa = 1743 kJ/mol) and the hydride ion (E pa = 1675 kJ/mol), [4] making methane the weakest proton acid [5] in the gas phase, followed by dihydrogen.
A variety of amines and nitrogen heterocycles are useful bases of moderate strength (pK a of conjugate acid around 10-13) . N,N-Diisopropylethylamine (DIPEA, also called Hünig's Base [1]), pK a = 10.75
DMA is prepared commercially by the reaction of dimethylamine with acetic anhydride or acetic acid. Dehydration of the salt of dimethylamine and acetic acid also furnishes this compound: [5] CH 3 CO 2 H·HN(CH 3) 2 → H 2 O + CH 3 CON(CH 3) 2. Dimethylacetamide can also be produced by the reaction of dimethylamine with methyl acetate. [6]
An ICE table or RICE box or RICE chart is a tabular system of keeping track of changing concentrations in an equilibrium reaction. ICE stands for initial, change, equilibrium . It is used in chemistry to keep track of the changes in amount of substance of the reactants and also organize a set of conditions that one wants to solve with. [ 1 ]
[69] [70] Buffering is an essential part of acid base physiology including acid–base homeostasis, [71] and is key to understanding disorders such as acid–base disorder. [ 72 ] [ 73 ] [ 74 ] The isoelectric point of a given molecule is a function of its p K values, so different molecules have different isoelectric points.
It undergoes directed ortho metalation with butyl lithium: [C 6 H 5 CH 2 N(CH 3) 2 + BuLi → 2-LiC 6 H 4 CH 2 N(CH 3) 2 LiC 6 H 4 CH 2 N(CH 3) 2 + E + → 2-EC 6 H 4 CH 2 N(CH 3) 2. Via these reactions, many derivatives are known with the formula 2-X-C 6 H 4 CH 2 N(CH 3) 2 (E = SR, PR 2, etc.).