A kind of synthetic method of 4,4-dimethyl-1,3-dioxane

Abstract

The invention relates to a 4,4-dimethyl-1,3-dioxane synthesis method. According to the 4,4-dimethyl-1,3-dioxane synthesis method, reaction monomers enter into a reactor respectively from different inlets, wherein an organic phase isobutene or isobutene-containing C4 fraction enters into the reactor from the lower part of the reactor and flows upward and a water phase phosphoric acid solution enters into the reactor from the upper part of the reactor and flows downward, the water phase material and the oil phase material contact in a counter current contact way in a multistage filling material zone and are fully dispersed so that a reaction is promoted, the reacted water phase is discharged from the bottom and the oil phase is discharged from the upper part. The 4,4-dimethyl-1,3-dioxane synthesis method has the advantages that a reaction conversion rate is high, reaction is thorough, formaldehyde-caused side reaction in the downstream process is greatly reduced, the reaction can be controlled easily, according to yield requirements, technical process conditions can be adjusted in the same reactor by adjustment of tertiary butanol and formaldehyde inlets so that the optimal reaction effects are obtained, and when the reaction occurs fluctuation, the reaction case can be improved and controlled by adjustment of the tertiary butanol and formaldehyde inlet positions.

Description

technical field

[0001] The present invention relates to the synthesis of chemical intermediates, in particular to a synthesis method of 4,4-dimethyl-1,3-dioxane. Background technique

[0002] Isoprene is an important chemical raw material, which can be separated from the cracked C5 fraction or obtained by chemical synthesis.

[0003] There are two main methods for synthesizing isoprene: one is the dehydrogenation method, that is, using isopentane or isopentene as a raw material to generate isoprene through catalytic dehydrogenation. There are two-step dehydrogenation method and one-step dehydrogenation method of isopentane. The other is the alkenal method, that is, using isobutene or the C4 fraction containing isobutene or tert-butanol and formaldehyde as raw materials to first synthesize the intermediate 4,4-dimethyl-1,3-dioxane, referred to as DMD, DMD then decomposes to obtain isoprene. The alkenal method is divided into gas phase alkenal method and liquid phase alkena...

Examples

preparation example Construction

[0054] This 4,4-dimethyl-1, the synthetic method of 3-dioxane comprises the following steps:

[0055] Phosphoric acid aqueous solution enters the reactor from the upper inlet between the upper packing area and the first intermediate packing area;

[0056] The aqueous formaldehyde solution enters the reactor from the first intermediate inlet located at the first intermediate packing area and the second intermediate packing area;

[0057] The tert-butanol aqueous solution enters the reactor from the second intermediate inlet between the second intermediate packing area and the lower packing area;

[0058] Isobutene enters the reactor from the lower inlet located below the lower packing area;

[0059] Phosphoric acid solution and formaldehyde flow from top to bottom in the reactor; part of tert-butanol flows from top to bottom with the water phase in the reactor, and part flows from bottom to top with the oil phase; isobutene flows from bottom to top in the reactor, Countercurr...

Embodiment 1

[0064] In this embodiment, the packing height of the lower packing area is 8m, the packing height of the second middle packing area is 1m, the packing height of the first middle packing area is 0.5m, and the packing height of the upper packing area is 0.5m; the packing is wound glass Glass springs are scattered in each packing area; the inner diameter of the reactor is

[0065] Isobutene: purity 99.9%; feed from the lower material distributor, flow rate 184g / h, feed temperature 70°C;

[0066] Tert-butanol aqueous solution: the content of tert-butanol is 85.1%, fed from the first intermediate material distributor, the flow rate is 220g / h, and the feed temperature is 85°C;

[0067] Formaldehyde aqueous solution: formaldehyde content 36.5%, methanol content 1.0%; flow rate 165g / h, feed temperature 86°C;

[0068] Phosphoric acid aqueous solution: phosphoric acid content 7.5%; flow rate 381g / h, feed temperature 86°C;

[0069] Formaldehyde aqueous solution and phosphoric ac...

Embodiment 2

[0075] Isobutene: purity 99.9%, fed from the lower feed distributor, flow rate 188g / h, feed temperature 71°C;

[0076] Tert-butanol aqueous solution: the content of tert-butanol is 85.1%, fed from the second intermediate feed distributor, the flow rate is 220g / h, and the feed temperature is 88°C;

[0077] Formaldehyde aqueous solution: formaldehyde content 36.5%, methanol content 1.0%, feed from the upper feed distributor, flow rate 140g / h, feed temperature 85°C;

[0078] Phosphoric acid aqueous solution: the phosphoric acid content is 7.2%, fed from the upper feed distributor, the flow rate is 369g / h, and the feed temperature is 85°C.

[0079] The first intermediate feed port is closed.

[0080] Control the reaction temperature in the reactor to be 85±5°C, and the reaction pressure to be 2.0±0.1MPa.

[0081] The outlet flow rate of the oil phase is 392g / h, and the outlet flow rate of the water phase is 500g / h.

[0082] The test results of oil phase and water phase are show...

technical field

[0001] The present invention relates to the synthesis of chemical intermediates, in particular to a synthesis method of 4,4-dimethyl-1,3-dioxane. Background technique

[0002] Isoprene is an important chemical raw material, which can be separated from the cracked C5 fraction or obtained by chemical synthesis.

[0003] There are two main methods for synthesizing isoprene: one is the dehydrogenation method, that is, using isopentane or isopentene as a raw material to generate isoprene through catalytic dehydrogenation. There are two-step dehydrogenation method and one-step dehydrogenation method of isopentane. The other is the alkenal method, that is, using isobutene or the C4 fraction containing isobutene or tert-butanol and formaldehyde as raw materials to first synthesize the intermediate 4,4-dimethyl-1,3-dioxane, referred to as DMD, DMD then decomposes to obtain isoprene. The alkenal method is divided into gas phase alkenal method and liquid phase alkena...

Examples

preparation example Construction

[0054] This 4,4-dimethyl-1, the synthetic method of 3-dioxane comprises the following steps:

[0055] Phosphoric acid aqueous solution enters the reactor from the upper inlet between the upper packing area and the first intermediate packing area;

[0056] The aqueous formaldehyde solution enters the reactor from the first intermediate inlet located at the first intermediate packing area and the second intermediate packing area;

[0057] The tert-butanol aqueous solution enters the reactor from the second intermediate inlet between the second intermediate packing area and the lower packing area;

[0058] Isobutene enters the reactor from the lower inlet located below the lower packing area;

[0059] Phosphoric acid solution and formaldehyde flow from top to bottom in the reactor; part of tert-butanol flows from top to bottom with the water phase in the reactor, and part flows from bottom to top with the oil phase; isobutene flows from bottom to top in the reactor, Countercurr...

Embodiment 1

[0064] In this embodiment, the packing height of the lower packing area is 8m, the packing height of the second middle packing area is 1m, the packing height of the first middle packing area is 0.5m, and the packing height of the upper packing area is 0.5m; the packing is wound glass Glass springs are scattered in each packing area; the inner diameter of the reactor is

[0065] Isobutene: purity 99.9%; feed from the lower material distributor, flow rate 184g / h, feed temperature 70°C;

[0066] Tert-butanol aqueous solution: the content of tert-butanol is 85.1%, fed from the first intermediate material distributor, the flow rate is 220g / h, and the feed temperature is 85°C;

[0067] Formaldehyde aqueous solution: formaldehyde content 36.5%, methanol content 1.0%; flow rate 165g / h, feed temperature 86°C;

[0068] Phosphoric acid aqueous solution: phosphoric acid content 7.5%; flow rate 381g / h, feed temperature 86°C;

[0069] Formaldehyde aqueous solution and phosphoric ac...

Embodiment 2

[0075] Isobutene: purity 99.9%, fed from the lower feed distributor, flow rate 188g / h, feed temperature 71°C;

[0076] Tert-butanol aqueous solution: the content of tert-butanol is 85.1%, fed from the second intermediate feed distributor, the flow rate is 220g / h, and the feed temperature is 88°C;

[0077] Formaldehyde aqueous solution: formaldehyde content 36.5%, methanol content 1.0%, feed from the upper feed distributor, flow rate 140g / h, feed temperature 85°C;

[0078] Phosphoric acid aqueous solution: the phosphoric acid content is 7.2%, fed from the upper feed distributor, the flow rate is 369g / h, and the feed temperature is 85°C.

[0079] The first intermediate feed port is closed.

[0080] Control the reaction temperature in the reactor to be 85±5°C, and the reaction pressure to be 2.0±0.1MPa.

[0081] The outlet flow rate of the oil phase is 392g / h, and the outlet flow rate of the water phase is 500g / h.

[0082] The test results of oil phase and water phase are show...

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