8 Commercial Production of Ionic Liquids
195
8.2.1.4 Purification of Solvents
For many synthesis protocols, the use of solvents is beneficial. Typical solvents are
dichloromethane, ethylacetate, acetonitrile, or methanol. To achieve the best ionic
liquid quality, it is required to operate with starting materials having the highest
commercially available purity or to purify them by following common purification
protocols.
8.2.2 Industrial Relevant Types of Reactions
It is difficult to draw a line where industrially relevant production starts and lab
scale ends; this depends on each application. The smallest batches we produce for
commercial purposes are in the range of 5 kg. So, for purposes of this book, lab scale
means below 5 kg, and commercial scale is 5 kg and above.
In the following, the most important examples of reactions are described.
8.2.2.1 Alkylation Reactions
Intermediate Ionic Liquids
To produce ionic liquid intermediates, numerous alkylating agents can be used. Many
ionic intermediates may also fall under the common definition of an ionic liquid.
Those ionic intermediates, such as [C 1 C 4 im][Cl], can be converted in a second step,
typically via an anion-exchange reaction, into other ionic liquids.
The most important commercially relevant intermediates are chlorides, bromides,
methylsulfates, hydroxides, and methylcarbonates.
Ionic Liquids Generated by Alkylation
In some cases, an industrially relevant ionic liquid can be directly synthesized by
alkylation. This is the case if the leaving group of the alkylating agent also becomes
the “final” anion. Good examples are [C 1 C 2 im][OTf] and [C 1 C 2 im][C 2 SO 4 ].
Quaternization of Amines and Derivatives
The quaternization of amines and N-heterocycles is by far the most important and
most frequently used synthesis in the field of ionic liquids. For this synthesis in
particular, alkyl halides are used, but of course other alkylating agents, such as
dialkylsulfates or alkyl triflates, just to name a few, can be used as well. The most
195
8.2.1.4 Purification of Solvents
For many synthesis protocols, the use of solvents is beneficial. Typical solvents are
dichloromethane, ethylacetate, acetonitrile, or methanol. To achieve the best ionic
liquid quality, it is required to operate with starting materials having the highest
commercially available purity or to purify them by following common purification
protocols.
8.2.2 Industrial Relevant Types of Reactions
It is difficult to draw a line where industrially relevant production starts and lab
scale ends; this depends on each application. The smallest batches we produce for
commercial purposes are in the range of 5 kg. So, for purposes of this book, lab scale
means below 5 kg, and commercial scale is 5 kg and above.
In the following, the most important examples of reactions are described.
8.2.2.1 Alkylation Reactions
Intermediate Ionic Liquids
To produce ionic liquid intermediates, numerous alkylating agents can be used. Many
ionic intermediates may also fall under the common definition of an ionic liquid.
Those ionic intermediates, such as [C 1 C 4 im][Cl], can be converted in a second step,
typically via an anion-exchange reaction, into other ionic liquids.
The most important commercially relevant intermediates are chlorides, bromides,
methylsulfates, hydroxides, and methylcarbonates.
Ionic Liquids Generated by Alkylation
In some cases, an industrially relevant ionic liquid can be directly synthesized by
alkylation. This is the case if the leaving group of the alkylating agent also becomes
the “final” anion. Good examples are [C 1 C 2 im][OTf] and [C 1 C 2 im][C 2 SO 4 ].
Quaternization of Amines and Derivatives
The quaternization of amines and N-heterocycles is by far the most important and
most frequently used synthesis in the field of ionic liquids. For this synthesis in
particular, alkyl halides are used, but of course other alkylating agents, such as
dialkylsulfates or alkyl triflates, just to name a few, can be used as well. The most