Alkoxide (also
called alcoholate ) is
the conjugate bases of corresponding alcohol. They
contain negatively charged oxygen atom, found as intermediaries in various
reactions. Alkoxide is a strong reducing
agent. The term
alkoxide is for
a compound formed from alcohol by replacing the hydrogen
of the hydroxy group by a monovalent metal. Metal alkoxides are versatile reagents
favoring the chemical reaction of condensation, esterification,
alkoxylation and etherification, Claisen condensation, Wolf-Kishner
reduction and Stobbe reaction are examples. They are used in wide range of
applications in organic synthesis; Agrochemicals; Pharmaceuticals, colorants and
aroma chemicals. They are used in manufacturing detergents and biodiesel. They
also act as catalysts in polymerization and isomerizations.
Base catalyzed reaction
Cleaning
Condensation
Dehalogenenation
Deprotonations
Elimination reaction
Enolate formation
Isomerization reaction
Polymer application
Selective metalation
Super base application
Transesterfication
Inorganic superbases are typically salts with highly charged, small negative
ions, e.g. lithium nitride, which has extreme negative charge density and so is
highly attracted to acids, like the aqueous hydronium ion. Alkali and earth
alkali metal hydrides (sodium hydride, calcium hydride) are superbases.
The
base strength can be varied with choice of solvent and the structure of the
alcohol. In the dimethyl sulfoxide (DMSO), the ion aggregates are solvated thus
increasing the basicity. Alkyl groups in steric bulk of the tertiary alcohol make
the
alcoholate a stronger base compared to primary alcoholates and
hydroxides and influence the speed, selectivity, and specificity. Generally
primary
alcoholate is soluble in the alcohol from which they are
derived only. But sec-, and tert- alcoholates are soluble in ethers. Furthermore
tert- alcoholates have high solubility in the hydrocarbons. In
organic synthesis, higher solubility of tertiary alcoholates can generate "
Schlosser base (or Lochmann-Schlosser base)" in combination with an alkyl
lithium to. The Schlosser base is a commonly used superbase. Butyllithium exists
as four-, or six-membered clusters, which are kinetically slow to react. The
tertiary alcoholate (butoxide) serves to complex the lithium ion, which breaks
the butyllithium clusters. This makes the butyllithium kinetically more
reactive. Other such systems are collectively called harpoon bases.
Alcoholate
|
CAS
RN
|
Sodium
Methylate |
124-41-4 |
Sodium
Ethylate |
141-52-6 |
Sodium
n-Propylate |
6819-41-6 |
Sodium
Isopropylate |
683-60-3 |
Sodium
n-Butylate |
2372-45-4 |
Sodium
tert-Butylate |
865-48-5 |
Sodium
tert-Amylate |
14593-46-5 |
Sodium
n-Hexylate |
19779-06-7 |
Sodium mentholate |
19321-38-1 |
Potassium
Methylate |
865-33-8 |
Potassium
Propylate |
16872-93-8 |
Potassium
Isopropylate |
6831-82-9 |
Potassium
Butylate |
589-39-9 |
Potassium n-Butylate |
3999-70-0 |
Potassium
tert-Butylate |
865-47-4 |
Potassium
tert-Amylate |
41233-93-6 |
Potassium-3,7-Dimethyl-3-Octylate
|
263148-42-1 |
|