1. What is n-propanol
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.
2. Review of the development of n-propanol in China
1. Before 2004
Production and development are relatively backward. There are only a dozen manufacturers producing small-scale products, mostly used for chemical reagents and solvents. Due to the small output, n-propanol still mainly relies on imports.
2. 2004–2008
Nuo’ao Chemical’s 50,000 tons/year n-propanol unit was put into operation, filling the gap in domestic production.
3. 2013
Nanjing Nuoao’s annual output of 100,000 tons of n-propanol project was officially completed and put into operation
4. 2014
Changchun Chemical (Panjin) Co., Ltd. was officially completed and put into operation.
3. China’s n-propanol market situation
Due to the different actual development conditions of the chemical industry in various countries, there are also great differences in the application of n-propanol. In China, n-propyl acetate is the largest consumer of n-propanol, with market demand accounting for about 65%, and its direct use as a solvent accounts for only about 8%. In the United States, the demand for direct use as a solvent is relatively high.
It is understood that the domestic production of n-propyl acetate in 2018 was about 150,000 tons, accounting for 65% of the total consumption of n-propanol. n-Propyl acetate is mainly used in ink, color printing, tobacco packaging, PTA dehydration and other industries.
The second place is pharmaceutical intermediates, which are expected to account for 12% of the total consumption of n-propanol. n-Propanol is used in the pharmaceutical industry to produce erythromycin, probenecid, sodium valproate, epileptic acid, adhesive hemostatic agent BCA, propylthioamine, dipropyl 2,5-pyridinedicarboxylate, etc.
The third place is pesticide intermediates, accounting for about 10% of the total consumption of n-propanol, which is used to produce the pesticides amisulfazine, fentanyl, isopropyl, sulfuramine, trifluralin Record etc.
At present, the production capacity of China’s n-propanol industry has been stable at around 142,000 tons (actual output is about 120,000 tons). There has been no new production capacity in the industry in the past two or three years, and China’s n-propanol consumption has increased in 2018 To 195,000 tons, China’s n-propanol production capacity is far from being able to meet China’s market demand for n-propanol, and a large amount needs to be imported. According to data, my country imported a total of 75,800 tons of n-propanol in 2018 to make up for the vacancies in the domestic market.
Figure-1 Distribution of downstream demand for n-propanol in mainland China
Figure-2 Distribution of n-propanol downstream regions in mainland China
4. Analysis of my country’s n-propanol import and export
In 2019, China still maintains a strong external dependence on n-propanol. According to data, from January to May 2019, my country’s n-propanol imports were 35,800 tons, and the cumulative exports from January to May were only 37.49 tons. Imports were far greater than exports. From January to May 2018, my country’s n-propanol imports totaled 28,900 tons, and from January to May 2019, the cumulative year-on-year growth rate was as high as 23.61%.
At present, there are few n-propanol industry manufacturers in China, and there are two production processes used. Nanjing Nuo Chemical Co., Ltd. and Nanjing Rongxin Chemical Co., Ltd. use the ethylene method, and Changchun Chemical (Panjin) Co., Ltd. The isopropanol (2-propanol) by-product method is used. The n-propanol products of the United States, Germany and Taiwan (Shengyi Chemical) have better performance indicators; n-propanol brands such as Sasol and Oxea have been working in the Chinese market for many years and have established good brand awareness, and imported products have Due to the advantages of large-scale production, product prices are often lower than those of domestic companies.
With the increase in the import volume of n-propanol, it has put great pressure on the development of local production enterprises in China. At the same time, because the price of n-propanol in China is not competitive in the domestic market, the export scale of n-propanol in China has been very large. Small, difficult to open the export market, which makes the development of China’s n-propanol industry more difficult.
Especially between 2015 and 2018, n-propanol originating in the United States was exported to China in large quantities, with the quantity increasing from 28,000 tons to 51,000 tons. It is estimated that from January to December 2018, the amount of n-propanol dumped by the United States to China was as high as 154.07%.
5. Analysis of n-propionaldehyde, the main raw material of n-propanol
N-propionaldehyde is the main raw material for the production of n-propanol, preservative raw material propionic acid, water-based polyester raw material dimethylol propionic acid, resin raw material trimethylol ethane, and water treatment acetone oxime; n-propionaldehyde It is also a polymerization inhibitor in the production of polyethylene, an accelerator and anti-aging agent for synthetic resins and rubbers, and can also be used as antifreeze, lubricant, dehydrating agent, etc.; n-propionaldehyde is widely used in medicine, paints, plastics, and spices. , rubber, food and feed industries.
Currently global production of propionaldehyde is approximately 580,000 tons, of which the United States accounts forThe ratio of propanol and ammonia is controlled, and then hydrogenated to obtain the product n-propylamine. The current domestic production capacity of n-propylamine is 18,000 tons.
In 2018, the apparent consumption of n-propylamine in China was only about 7,500 tons, with 90% of its demand concentrated in the pesticide industry, and the remaining proportions in coatings, textiles, resin finishing agents, synthetic flavors, feed additives, petroleum additives, anticorrosion and other industries. 10%.
10. Application of n-propanol in the coating industry
1. Toxicity
People have not yet discovered an ideal industrial solvent that is non-flammable, non-explosive, non-toxic and non-harmful to the skin. Solvents that have no risk of fire or explosion are often toxic to physiology; solvents that are not toxic to physiology can easily catch fire.
The melting point, boiling point, vapor pressure, vapor density and the evaporation rate of the solvent all determine how easy it is for the solvent to invade the human body; the solubility or distribution coefficient of the solvent in water and fat determines the way the solvent passes through the respiratory, digestive tract or How easily it is absorbed into the skin.
Based on the health damage classification of solvents, n-propanol belongs to Category 1: weakly toxic solvents.
2. Important characteristics as a coating solvent
A. Compatibility
The chosen solvent must have good compatibility with other solvents in the system. n-Propanol has good compatibility with other solvents.
B. Solubility
The solvent should have certain solubility for specific resins. n-Propanol has very good dissolving power for acrylic resin/alkyd resin, etc.
C, boiling point
It is very important to match the boiling point of other solvents, and it should not be too different from other solvents in the system. Boiling point of n-propanol: 97.2’C, matching the boiling point of the main solvent used in coatings.
Volatilization rate
The selected solvent must match the evaporation rate of other solvents in the system. n-Propanol evaporation rate: 0.89, quite moderate.
The reason why n-propanol is not widely used in coatings in China: Due to the hydroxyl group and strong hydrogen bonding, there are not many alcohol solvents used in the coating itself; n-propanol used to have few manufacturers, and the price was high and fluctuated; manufacturers promoted Not strong enough.
11. Application of n-propyl acetate in the coating industry
n-Propyl acetate:
1. Miscible with almost all organic solvents and slightly soluble in water;
2. It has strong solubility in oils and can dissolve all natural oils except palm oil. It can also dissolve cellulose nitrate, phenolic resin, vinyl resin, etc., but does not dissolve cellulose acetate;
p>
3. Used as the main solvent or co-solvent to dissolve rosin, nitrocellulose, polystyrene, polyacrylate, PU, NBR, and SBS in the production of adhesives and coatings;
4. It has good solubility in various metal halides such as copper chloride, mercury chloride, ferric chloride, etc.
5. The solubility of mixed solvents composed of n-propyl acetate and alcohol solvents will be greatly increased, such as mixed solvents with ethanol. Can dissolve difficult-to-dissolve phthalic acid resin, etc.
n-Propyl acetate is used as a slow-drying and quick-drying agent in flexographic and gravure printing inks, especially for reducing olefins
And polyamide film printing; it is also a flavor and fragrance solvent allowed to be used according to my country’s GB2760-86.
Important properties of n-propyl acetate as a coating solvent
A. Compatibility
The chosen solvent must have good compatibility with other solvents in the system. n-Propyl acetate has good compatibility with other solvents.
B. Solubility
The solvent should have certain solubility for specific resins. n-Propyl acetate has very good solubility for acrylic resin/alkyd resin, etc.
C, boiling point
It is very important to match the boiling point of other solvents, and it should not be too different from other solvents in the system. Boiling point: 101.6’C, matching the boiling point of the main solvent used in coatings.
D. Evaporation rate
The selected solvent must match the evaporation rate of other solvents in the system. Evaporation rate: 2.1, quite moderate. It is reliable to use n-propyl acetate as the main solvent of paint.
Prospect Analysis
In recent years, with the rapid development of coatings, spray paints, inks, adhesives and other industries, as well as the continuous improvement of national environmental protection requirements, downstream industries have limited the use of triphenyl solvents that are not easily degraded in the environment. Replaced by acetate solvents, the market demand for acetate products is growing.
In recent years, driven by the development of downstream coatings, spray paints, inks, adhesives and other industries, as well as the tightening of national environmental protection policies, the consumption of low-toxic n-propanol has continued to grow. The application advantages of n-propanol are relatively obvious. In the future, as the environmental protection requirements of the coating industry continue to increase, n-propanol is expected to replace n-butanol, isopropyl alcohol, and acetate and become the most important solvent in the coating field. The market development prospects are bright.
In recent years, as the consumption of environmentally friendly solvents has increased year by year, the market demand for n-propanol has also shown continued growth. However, due to the insufficient supply of domestically produced n-propanol, my country’s import volume of n-propanol increased from about 17,000 tons in 2008 to more than 38,000 tons in 2012. In 2012, the import dependence reached about 40%.
