Friedel-Crafts reactions . Various chemical compounds are manufactured by applying the Friedel-Crafts condensation reaction.
Summary
[ hide ]
- 1 Stages of the process
- 2 Consequences of humidity
- 3 Speed of reaction
- 4 Sources
Stages of the process
The efficient operation of this process will depend on:
- Preparation and handling of reactants.
- The design and construction of the apparatus.
- Control the reaction in such a way that only the desired product is practically formed.
- CatalystStorage ( Aluminum Chloride )
Consequences of humidity
Several of the initial reactants, such as acid anhydrides, acid chlorides, and alkyl halides, are susceptible to hydrolyze. The absorption of moisture by these chemical compounds will lead to the production of compounds that will be less active, will require higher amounts of aluminum chloride for condensation, and will generally lead to lower amounts of the desired product. Furthermore, the ingress of moisture into the storage containers of these active components will usually bring about corrosion problems.. Anhydrous aluminum chloride needs to be stored in iron tanks under conditions where the absence of moisture is ensured. In this way, when the humidity makes contact with the aluminum chloride, hydrogen chloride will be formed, so the amount of hydrogen chloride formed will depend on the amount of water and the degree of agitation of the halide. If a sufficient amount of moisture is present, particularly in the free space of the reaction container or vessel, or at the point of contact with the outside atmosphere, then hydrochloric acid will form and will lead to corrosion of the storage container. In certain reactions, such as isomerization of butaneand alkylation of isoparaffins, problems can be encountered in handling hydrogen chloride and acidic residue. The corrosive action of the aluminum chloride-hydrocarbon complex, particularly at 70 – 100 ºC, has been extensively recognized, therefore the use of several lined reactors is recommended.
Reaction speed
The reaction rate is a function of the efficiency of the contact between the reactant compounds, that is, the stirring and mixing mechanism of the reactants. In fact, mixing efficiency has a vital influence on the performance and purity of the final product. Insufficient or inefficient mixing can lead to the formation of uncondensed reactants, or to excessive reaction on hot surfaces.
