Production process of n-propanol_Industrial additives

What is n-propyl alcohol

n-Propanol is:

1. Transparent liquid;

2. Has a mellow aroma;

3. Melting point -126.2℃, boiling point 97.2℃;

4. It is miscible with water, alcohol, ether, hydrocarbon and other solvents, and can be used directly as a solvent, or can be used as a solvent after synthesizing n-propyl acetate.

5. The chemical properties of n-propanol are similar to other low molecular weight aliphatic primary alcohols, and it is a chemical product with a wide range of uses;

6. It can also be synthesized into n-propylamine, di-n-propylamine, etc. and used in the agricultural field, or various esters can be synthesized and used in many aspects such as food additives, plasticizers, and spices.

It is currently widely used in products such as coatings, paints, adhesives, cosmetics, plastics and fungicides. It is also an important raw material in many fields such as food additives, feed additives, synthetic flavors, detergents, preservatives and brake oil. . In addition, n-propanol also has very important uses in the field of pharmaceutical intermediates.

Production process of n-propanol

Currently there are more than five n-propanol production processes in the world. The most common processes are the first three. The existing n-propanol production processes in China are the first two:

1. Ethylene carbonyl synthesis of propionaldehyde, propionaldehyde catalytic hydrogenation to produce n-propanol;

2. Hydrogenation of allyl alcohol to produce 1,4-butanediol as a by-product of n-propanol;

3. Propylene is directly hydrated to produce isopropanol as a by-product of n-propanol;

4. Propylene oxide hydrogenation method;

5. Separation method from the oxides of lower alkanes.

Table-1 Summary of domestic n-propanol production companies in 2019

In 2019, the total production capacity of China’s n-propanol market was 142,000 tons. The production of n-propanol through ethylene oxo synthesis is the most important domestic production process, accounting for 84.5% of the country’s total production capacity. The production capacity of allyl alcohol hydrogenation method is 15,000 tons, accounting for 10% of the total domestic production capacity. Analysis of characteristics of each production process:

1. Vinyl carbonyl synthesis method

This process uses ethylene, synthesis gas, and hydrogen as raw materials to produce propionaldehyde through a low-pressure oxo synthesis process, and then produces n-propanol through a gas-phase hydrogenation process. This process has the advantages of short process flow, low energy consumption, low equipment cost, stable and reliable operation control, and low emission of three wastes. It is currently the most advanced production process technology route in the world.

2. Allyl alcohol hydrogenation method

Starting from allyl alcohol, a hydroformylation reaction is used to generate 4-hydroxybutyraldehyde, which is then hydrogenated to produce 1,4-butanediol. This method has the advantages of low investment, low energy consumption, recyclable catalyst, safe reaction, and high utilization value of by-products (n-propanol, 2-methyl-1,3-propanediol). It is a method with promising prospects for promotion. The disadvantage is smaller production capacity.

3. Recovery method from isopropyl alcohol by-products

When propylene is directly hydrated to produce isopropanol, the by-product is n-propanol, which is recovered to produce n-propanol. The production capacity of the by-product n-propanol obtained by this method is small.