Synthesis of caprolactam and its oligomer

Abstract

The present invention is synthesis process of caprolactam and its oligomer. Cyclohexane as initial material is nitrosated with nitroso sulfuric acid inside fuming sulphuric acid medium and in the presence of catalyst to synthesize caprolactam and its oligomer directly. The present invention has greatly simplified technological process, lowered cost and greatly raised resource utilization.

Description

technical field

[0001] The invention relates to a synthesis method of caprolactam and its oligomers. Background technique

[0002] Caprolactam is a very important petrochemical product, mainly used in the production of nylon 6 fibers and nylon 6 engineering plastics. The former is widely used in wool spinning, needle weaving, cord fabrics and carpets, and the latter is widely used in electronics, automobiles and Packaging film and other industries. It also produces several organic compounds, as well as L-lysine necessary for conversion to biology and nutrition.

[0003] At present, the industrialization technology of caprolactam mainly includes cyclohexanone-hydroxylamine method, cyclohexane photonitrosation method and toluene method.

[0004] The cyclohexanone-hydroxylamine route is currently the most mature and widely used method for producing caprolactam in industry. First, cyclohexane is oxidized to prepare cyclohexanone, and then cyclohexanone is reacted with hydroxy...

Examples

Embodiment 1

[0020] Embodiment 1: by cyclohexane: nitrosyl sulfuric acid: nicotinic acid=10g: 4g: 4g material is packed in the 100mL glass reactor, reaction temperature 81 ℃, time 24h, the amount of catalyst accounts for cyclohexane 5%, the reacted mixture is divided into two layers, the upper layer is a colorless and transparent liquid which is cyclohexane, the lower layer is a viscous solid which is caprolactam, the remaining reactant nitrosylsulfuric acid, nicotinic acid and by-products. After liquid separation, the upper layer is weighed and analyzed by gas chromatography, and the lower layer is neutralized with barium hydroxide to remove SO 4 2- analyzed by liquid chromatography.

[0021] catalyst

[0022] The generated oligomers are dimers and trimers of caprolactam, and the dimers and trimers of caprolactam are not included in the selectivity calculation of caprolactam.

Embodiment 2

[0023] Embodiment 2: cyclohexane: nitrosyl sulfuric acid: nicotinic acid=10g: 4g: 4g, the steps are the same as in Example 1, the difference is that 2g of glacial acetic acid is used as a catalyst, the reaction temperature is 81°C, and the time is 24h. The final mixture is divided into two layers, the upper layer is a colorless transparent liquid of cyclohexane, the lower layer of viscous solid is caprolactam, the remaining reactant nitrosylsulfuric acid and nicotinic acid and by-products. After liquid separation, the upper layer was weighed and analyzed by gas chromatography. Add a small amount of double distilled water to the solid in the lower layer in an ice bath, then slowly add concentrated ammonia water dropwise to neutralize to a pH of 8-9, then extract three times with an equal volume of ether, and use a certain amount of anhydrous Na 2 SO 4 Dry, add a certain amount of water or methanol to dissolve the residue after removing ether, and analyze it by liquid chromatog...

Embodiment 3

[0027] Embodiment 3: cyclohexane: nitrosyl sulfuric acid: nicotinic acid=10g: 4g: 4g, the steps are the same as in Example 1, the difference is that with 5% CuO / η-Al 2 o 3 It is a catalyst, the amount of the catalyst accounts for 1% of cyclohexane, the reaction temperature is 81 ° C, and the time is 24 hours. The mixture after the reaction is divided into two layers. The upper layer is a colorless transparent liquid. Reactants nitrosylsulfuric acid and nicotinic acid and by-products. After liquid separation, the upper layer is weighed and analyzed by gas chromatography, and the lower layer solid is processed by two methods:

[0028] 1. with embodiment 2; 2. with embodiment 1.

[0029] Cyclohexane conversion: 5.90%

[0030] Caprolactam selectivity: 0.67% (processing mode is the same as embodiment 2)

[0031] 3.16% (processing mode is the same as embodiment 1)

[0032] The generated oligomers are dimers and trimers of caprolactam, and the dimers and trimers ...

technical field

[0001] The invention relates to a synthesis method of caprolactam and its oligomers. Background technique

[0002] Caprolactam is a very important petrochemical product, mainly used in the production of nylon 6 fibers and nylon 6 engineering plastics. The former is widely used in wool spinning, needle weaving, cord fabrics and carpets, and the latter is widely used in electronics, automobiles and Packaging film and other industries. It also produces several organic compounds, as well as L-lysine necessary for conversion to biology and nutrition.

[0003] At present, the industrialization technology of caprolactam mainly includes cyclohexanone-hydroxylamine method, cyclohexane photonitrosation method and toluene method.

[0004] The cyclohexanone-hydroxylamine route is currently the most mature and widely used method for producing caprolactam in industry. First, cyclohexane is oxidized to prepare cyclohexanone, and then cyclohexanone is reacted with hydroxy...

Examples

Embodiment 1

[0020] Embodiment 1: by cyclohexane: nitrosyl sulfuric acid: nicotinic acid=10g: 4g: 4g material is packed in the 100mL glass reactor, reaction temperature 81 ℃, time 24h, the amount of catalyst accounts for cyclohexane 5%, the reacted mixture is divided into two layers, the upper layer is a colorless and transparent liquid which is cyclohexane, the lower layer is a viscous solid which is caprolactam, the remaining reactant nitrosylsulfuric acid, nicotinic acid and by-products. After liquid separation, the upper layer is weighed and analyzed by gas chromatography, and the lower layer is neutralized with barium hydroxide to remove SO 4 2- analyzed by liquid chromatography.

[0021] catalyst

[0022] The generated oligomers are dimers and trimers of caprolactam, and the dimers and trimers of caprolactam are not included in the selectivity calculation of caprolactam.

Embodiment 2

[0023] Embodiment 2: cyclohexane: nitrosyl sulfuric acid: nicotinic acid=10g: 4g: 4g, the steps are the same as in Example 1, the difference is that 2g of glacial acetic acid is used as a catalyst, the reaction temperature is 81°C, and the time is 24h. The final mixture is divided into two layers, the upper layer is a colorless transparent liquid of cyclohexane, the lower layer of viscous solid is caprolactam, the remaining reactant nitrosylsulfuric acid and nicotinic acid and by-products. After liquid separation, the upper layer was weighed and analyzed by gas chromatography. Add a small amount of double distilled water to the solid in the lower layer in an ice bath, then slowly add concentrated ammonia water dropwise to neutralize to a pH of 8-9, then extract three times with an equal volume of ether, and use a certain amount of anhydrous Na 2 SO 4 Dry, add a certain amount of water or methanol to dissolve the residue after removing ether, and analyze it by liquid chromatog...

Embodiment 3

[0027] Embodiment 3: cyclohexane: nitrosyl sulfuric acid: nicotinic acid=10g: 4g: 4g, the steps are the same as in Example 1, the difference is that with 5% CuO / η-Al 2 o 3 It is a catalyst, the amount of the catalyst accounts for 1% of cyclohexane, the reaction temperature is 81 ° C, and the time is 24 hours. The mixture after the reaction is divided into two layers. The upper layer is a colorless transparent liquid. Reactants nitrosylsulfuric acid and nicotinic acid and by-products. After liquid separation, the upper layer is weighed and analyzed by gas chromatography, and the lower layer solid is processed by two methods:

[0028] 1. with embodiment 2; 2. with embodiment 1.

[0029] Cyclohexane conversion: 5.90%

[0030] Caprolactam selectivity: 0.67% (processing mode is the same as embodiment 2)

[0031] 3.16% (processing mode is the same as embodiment 1)

[0032] The generated oligomers are dimers and trimers of caprolactam, and the dimers and trimers ...

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