Allyl alcohol . Allyl alcohol (2-propene-1-ol; CH 2 = CHCH 2 OH, boiling point: 96.9 ºC; density: 0.8520) is the simplest unsaturated alcohol, and is a colorless, corrosive liquid with a sour odor. Allyl alcohol is miscible in water and in many polar organic solvents and aromatic hydrocarbons , although it is not miscible in n-hexane (C 6 H 14 ). It forms an azeotropic mixture with water, and a ternary azeotropic mixture with water and organic solvents.
Summary
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- 1 Obtaining
- 2 Use
- 3 Risks to human health
- 4 Sources
Obtaining
There are 4 processes to obtain allyl alcohol.
- In the first, the alkaline hydrolysis of the allyl chloride (CH 2= CHCH 2 Cl) is carried out. In this process a control of the amounts of allyl chloride, the 20 wt% sodium hydroxide aqueous solution (NaOH), the water and the steam are carried out as they are added to the reactor . Hydrolysis is carried out at 150 ° C temperature, 200 lb / in2 pressure (1.4 MPa) and at a pH between 10 to 12. Under these reaction conditions, the conversion of the allyl chloride is around 97 – 98%, while allyl alcohol is selectively produced at 92-93% yield. The main by-product is diallyl ether (CH 2= CHCH 2 OCH 2 CH = CH 2 ). At high alkali concentrations, the amount of this by-product increases, while at low alkali concentrations the conversion of allyl chloride will not increase.
- The second process has two stages. The first of these consists of the oxidation of propylene (CH 3CH = CH 2 ) to acrolein (CH 2 = CHCHO), while in the second, the reduction of acrolein to allyl alcohol (CH 2 = CHCH 2) is carried out OH) by a hydrogen transfer reaction , using isopropyl alcohol [(CH 3 ) 2 CHOH].
- In the third method, the isomerization of propylene oxide (CH 2CHCH 2 O) is carried out in the presence of a catalyst (lithium phosphate, Li 3 PO 4 ). In this process, the fine lithium phosphate powder used as a catalyst is dispersed, and the propylene oxide is fed at 300 ºC to the reactor, while the allyl alcohol product, together with the propylene oxide that did not react, is removed by distillation . By-products such as acetone will form (CH 3 COCH 3) and propionaldehyde, which are isomers of propylene oxide, although the conversion of propylene oxide is 40% and the selectivity to allyl alcohol reaches more than 90%. Allyl alcohol obtained by this method may contain small amounts (<1%) of propanol (CH 3 CH 2 CH 2 OH).
- The fourth allyl alcohol production process was partially developed with the objective of producing epichlorohydrin (CH 2OCHCH 2 Cl), using allyl alcohol as an intermediate product and a palladium catalyst.
Use
Allyl alcohol exhibits both bactericidal and fungicidal properties , and has been used as such or as a source to obtain derivatives that have these effects.
Risks to human health
The vapor can cause severe irritation and damage to the eyes , nose , throat and lungs .
