Preparation and application of n-propanol_Industrial additives

Background and overview^[1]

n-Propanol is a colorless and transparent liquid with a boiling point of 97.15°C. Soluble in water, flammable. Mainly used as solvent and organic synthesis intermediate. In the United States, about 40% of n-propanol is directly used as a solvent or to synthesize propyl acetate, which is used in coating solvents, printing inks, cosmetics, etc.; 40% is used to produce n-propylamine, an intermediate for medicines and pesticides; 20% is used to produce feed. Additives, synthetic flavors, etc.

n-Propanol is produced by hydrogenation of propionaldehyde. The catalysts used include cobalt or rhodium carbonyl compounds, ruthenium complexes, skeleton catalysts (such as nickel, copper), etc. The most commonly used are skeleton catalysts. The hydrogenation reaction can be homogeneous or heterogeneous. The latter can be divided into liquid phase hydrogenation and gas phase hydrogenation. Liquid-phase hydrogenation mostly uses nickel-based catalysts; gas-phase hydrogenation mostly uses copper-based catalysts. The trend in the past decade has been to use copper-zinc oxide catalysts. The reactors are fixed bed reactors, slurry reactors, and trickle bed reactors.

Preparation^[2]

The clean production process of hydrogenating propionaldehyde to n-propanol includes the following steps:

a. When propionaldehyde is hydrogenated to produce crude propanol and enters the distillation system, the light removal tower condenses the three-phase azeotrope residue formed by the reaction by-product propyl propionate, water and n-propanol. After heat exchange, it is passed into the pervaporation membrane dehydration device;

b. The gas phase material separated by the pervaporation membrane dehydration device is condensed to obtain wastewater A. The wastewater A is mixed with the raw material propionaldehyde and enters the system again. The condensed residual gas is evacuated by the vacuum pump; the wastewater A separated by the pervaporation membrane dehydration device is The liquid phase material is sent to rectification to separate n-propanol and propyl propionate in the liquid phase material.

Purification^[3]

A method for preparing chromatographically pure propanol. The specific preparation steps are as follows:

(1) Take 50g of nutshell activated carbon, dry it at 150℃ for 8 hours, then put it in a desiccator to cool down and set aside;

(2) Take 1000ml of analytically pure propanol and put it into the extraction bottle. Add 50g of the activated carbon pre-treated in step (1) and shake for 30 minutes. Leave it for 10 hours. Filter to separate the activated carbon. Put 1000ml of n-propanol. In a three-necked distilling bottle;

(3) After installing the distillation equipment as required, further distill n-propanol in step (2), adjust the reflux ratio to 2:30, collect 96.5-97.5 fractions, and obtain chromatographically pure n-propanol, take samples and analyze , the inspection is based on Q/12HB3730-2010 standard inspection, and the finished product yield is about 88%.

Apply^[4-6]

n-Propanol is a good solvent and can be used directly or through the synthesis of propyl acetate in coatings, printing inks, daily chemicals and other fields. n-Propanol can be used as raw material to synthesize n-propylamine, propyl acetate, propyl urea, 2-methyl-2-pentanol, n-bromopropane, perfluoropropionic acid, propyl parahydroxybenzoate and propylparaben, etc. . n-Propanol is used in the pharmaceutical industry to produce probenecid, sodium valproate, erythromycin, propylamine sulfate, dipropyl 2,5-pyridinedicarboxylate, etc. The most important derivative of n-propyl alcohol is n-propylamine, which is mainly used in the production of pesticides oryzalin, clofenac, isopropylamine, trifluralin, clofenac, etc.

1) CN201580031014.2 discloses a method for preparing polybutene using a catalyst containing n-propanol, in which the content of vinylene is 40 to 70% and the content of four-substituted double bonds is 10% or more , and a composite catalyst containing n-propanol as a cocatalyst and a main catalyst such as boron trifluoride was used. The method for preparing polybutene using a catalyst containing n-propanol includes: adding a composite catalyst including n-propanol as a cocatalyst and boron trifluoride as a main catalyst to a reaction raw material containing 10 wt% or more isobutylene. ; Polymerize the reaction raw materials at a reaction pressure of 3 to 50 kg/cm2 and a reaction temperature of 33 to 33°C, wherein the content of the vinylidene group is adjusted by controlling the reaction temperature.

2) CN201810178425.X discloses a new synthesis process of propoxyacetic acid. The process includes the following steps: 1) Reaction: Disperse sodium propoxide in n-propanol, and dropwise add n-propanol solution of chloroacetic acid into it; after the dropwise addition is completed, keep the reaction warm and acidify with concentrated hydrochloric acid; (2) Demineralization : Filter the generated sodium chloride, rinse the filter cake with n-propanol, and combine the filtrate and eluent; (3) Distillation: After combining the filtrate and eluent, distill under reduced pressure to recover n-propanol to obtain the product . The invention has beneficial effects: the reaction is close to quantitative, and the total product yield is as high as 98%; the wastewater does not contain salt and is close to pure water, and all its indicators meet the wastewater discharge standards and can be discharged directly without causing environmental pollution or increasing Three waste treatment costs; the filtered salt is washed with n-propanol to recover useful components and then dried, which can be sold as a by-product.

Main reference materials

[1]Encyclopedia of China (Chemical Engineering Volume)

[2]CN201010113521.X A clean production process for preparing n-propanol by hydrogenating propionaldehyde

[3]CN201310739146.3 A method for preparing chromatographically pure n-propanol

[4]CN200710041506.7 A method for preparing n-propanol by hydrogenating glycerol

[5]CN201580031014.2 Method for preparing polybutene using a catalyst containing n-propanol

[6]CN201810178425.X A new synthesis process of propoxyacetic acid