2- Pentanol

Colourless, volatile liquid with a strong pearlike odour, b.p. 138-5 C. Manufactured by heating amyl alcohol (1-pentanol) with potassium ethanoate and sulphuric acid or by heating amyl alcohol with ethyl ethanoate in the presence of a little sulphuric acid. Commercial... 

Mixtures of isomeric amyl alcohols (1-pentanol and 2-methyl-1-butanol) are often preferred because the different degree of branching imparts a more desirable combination of properties they are also less expensive to produce commercially. One such mixture is a commercial product sold under the name Primary Amyl Alcohol by Union Carbide Chemicals and Plastics Company Inc. 

Properties 1-Pentanol 2-Pentanol 3-Pentanol 2-Methyl-1 -butanol 3-Methyl-l -butanol 2-Methyl-2 -butanol 3-Methyl-2 -butanol 2,2-Dimeth5i -1-propanol... 

Commercial primary amyl alcohol is a mixture of 1-pentanol and 2-methyl-1-butanol, iu a ratio of ca 65 to 35 (available from Union Carbide Chemicals and Plastics Company Inc. iu other ratios upon request). Typical physical properties of this amyl alcohol mixture are Hsted iu Table 2 (17). 

Fig. 1. Viscosities of amyl alcohols compared with 1-butanol and 1-hexanol (15). a, 1-butanol b, 2-methyl-2-butanol c, 1-pentanol d, 2-methyl-1-butanol ...

Dehydration of 1-pentanol or 2-pentanol to the corresponding olefins has been accompHshed, in high purity and yields, by vapor-phase heterogeneous catalyzed processes using a variety of catalysts including neutral gamma —Al Og catalyst doped with an alkah metal (23), zinc aluminate (24,25), hthiated clays (26), Ca2(P0 2 montmorillonite clays (28). Dehydration of 2-methyl-1-butanol occurs over zinc aluminate catalyst at... 

C to give the expected 2-methyl-1-butene in high selectivites (24). The AI2O2 catalyzed process can be optimized to give di- -pentyl ether as the exclusive product (23). Dehydration of 1-pentanol over an alkah metal promoted AI2O2 catalyst at 300—350°C provides 1-pentene at selectivities of 92% (29,30). Purification produces polymerization grade (99.9% purity) 1-pentene. A flow chart has been shown for a pilot-plant process (29). 

---