Reagents for distinguishing between n-butanol and sec-butanol

1. Using spin-out test to distinguish between n-butanol and sec-butanol

The spin-out test is a quick and economical method to distinguish between n-butanol and sec-butanol. The spin-out property refers to the speed at which the liquid is spun out from the edge of the container during rotation, which is related to the molecular weight. The larger the molecular weight, the stronger the spin-out property of the liquid.

• Test steps:

1. Pour the liquid to be tested into the spinner test cup.
2. Use a spinner tester to rotate the cup at the same speed.
3. Observe the liquid from the cup out of the speed.

• Result analysis:
• Butanol spin out of the weak, spin out speed is low.
• Secondary butanol spin out of strong, spin out faster.

By this method, it is possible to quickly determine whether the liquid is n-butanol or sec-butanol.

2. Using iodine test method to distinguish between n-butanol and sec-butanol

Iodine test is a classical chemical test method, which uses the reaction characteristics of iodine under specific conditions to distinguish chemical substances.

• Test steps:

1. The test liquid was added to the iodine-containing solution.
2. Oscillation mixing uniform.
3. Observe whether there is a blue precipitate.

• Result analysis:
• Butanol at room temperature does not react with iodine, no blue precipitate.
• Secondary butanol at room temperature with iodine transesterification reaction, the formation of acetic acid, the solution is blue.

By this method, it is possible to determine whether the liquid is sec-butanol.

,3. Combined with spin-out test and iodine test method comprehensive analysis

In order to distinguish n-butanol and sec-butanol more accurately, the spin-out test can be combined with the iodine test method:

• Test steps:

1. First, conduct a spin-out test to judge the spin-out speed.
2. If the spinning speed is faster, then carry out the iodine test.

• Result analysis:
• If the spin-out speed is slow and the iodine test method has no blue precipitate, it is n-butanol.
• If the spin-out speed is faster and the iodine test method appears blue precipitate, it is sec-butanol.

This method combines spin-out and chemical reaction characteristics to more accurately distinguish between the two alcohols.

Summary

There are various methods to distinguish between n-butanol and sec-butanol, and the spin-out test and iodine test are two classic test methods. The spin-out test is quickly judged by the difference in molecular weight, while the iodine test is assisted by the chemical reaction characteristics. Combined use of these two methods can improve the accuracy of discrimination. In actual operation, selecting the appropriate method and combining the experimental conditions can efficiently confirm the type of liquid and ensure the production quality and application safety.