Reaction device for synthesizing dipropylene glycol

Abstract

Epoxy propane and propylene glycol are used as raw materials, an acid or alkaline substance is used as a catalyst, condensation reaction is performed to obtain DPG, a kettle type reactor and a tubular reactor are generally adopted, a large amount of heat is released in the reaction, so that an external heat exchanger is needed to remove heat, and the generated DPG is mixed back into the reactor in the material circulation process, so that the DPG is generated. The utility model relates to a dipropylene glycol reaction device, which aims to solve the technical problems of low DPG conversion rate, more by-product tripropylene glycol and the like of the existing dipropylene glycol reaction device, and the technical problem that the existing dipropylene glycol reaction device is low in price due to the fact that the byproduct tripropylene glycol accounts for about 15%-25% of the DPG, and the economical efficiency of the device is poor due to the small market price of the tripropylene glycol. The reaction device which is simple and convenient to operate and capable of reducing DPG backmixing is provided, and the by-product tripropylene glycol is reduced by 50% or above.

Description

TECHNICAL FIELD

[0001] The utility model relates to a reaction device of one shrinked dipropylene glycol, which is synthesized by taking propylene oxide and propylene glycol as raw materials. BACKGROUND

[0002] Dipropylene glycol (abbreviated as DPG) is a colorless and odorless liquid at room temperature, which has little corrosiveness and skin irritation, and low toxicity, and is widely used. It can be used as a moisturizing agent, a solvent, a thickening agent and the like for cosmetics and personal care, and is applied to solvents, antifreezing agents, lubricants and the like in industry, and can also be used as a food additive, a drug carrier, a moisturizing agent for tobacco industry, a softening agent and an antistatic agent for textiles.

[0003] There are mainly two traditional industrial production methods of dipropylene glycol. One is a large amount of DPG by-product generated in the production process of polyether, which has low quality and can only be used as an industrial solvent and a production raw material for some chemical products. The other is to condense propylene glycol (abbreviated as PG) and propylene oxide (abbreviated as PO), and then to obtain DPG through vacuum rectification, and to generate tripropylene glycol (abbreviated as TPG) as a by-product. The DPG obtained by this method has high content and low color, and is mainly applied to fields requiring high-quality raw materials such as perfumes, cosmetics, detergents and food additives.

[0004] Propylene oxide and propylene glycol are used as raw materials, and acid or alkaline substances are used as catalysts to carry out condensation reaction to obtain DPG. A kettle type reactor and a tubular reactor are usually used. Since a large amount of heat is generated during the reaction, an external heat exchanger is needed to remove the heat. The circulation of this part of material causes the generated DPG to return to the reactor, so that DPG and propylene oxide contact to generate tripropylene glycol. The by-product tripropylene glycol accounts for about 15% to 25% of DPG. Since the market of tripropylene glycol is small and the price is low, the economic efficiency of the device is poor. Therefore, how to develop a device which is more simple to operate, reduces the return mixing of DPG, improves the conversion rate of DPG and reduces the generation of by-product tripropylene glycol is the key to solve the above problems. SUMMARY

[0005] The utility model discloses to the existing dipropylene glycol reaction device low DPG conversion rate, by-product tripropylene glycol many technical problems, propose a kind of operation simple, reduce the reaction device of DPG return mixing.

[0006] In order to achieve the above purpose, the utility model adopts the technical scheme that:

[0007] A reaction device for synthesizing dipropylene glycol, which adopts a plate reactor, and cooling water or material is arranged between the plates, and raw propylene glycol and raw propylene oxide are fed into the plates, characterized in that two streams of raw materials are fed into the plates separately, and a double helix mixer is arranged, and the flow channel in the plate is provided with convex eight-shaped or herringbone patterns, the width of the flow channel in the plate is 1-5 cm, and the length of the flow channel in the plate satisfies the material residence time of 10 minutes.

[0008] In the above, a reaction device for synthesizing dipropylene glycol, wherein the feeding ratio of raw propylene glycol and raw propylene oxide is 1:1-3:1 (molar ratio);

[0009] In the above, a reaction device for synthesizing dipropylene glycol, wherein the reaction pressure is controlled to be 0-2 MPaG, and preferably 0.6-1.2 MPaG;

[0010] In the above, a reaction device for synthesizing dipropylene glycol, wherein the reaction temperature is controlled to be 60-180℃, and preferably 80-120℃. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 It is a structure diagram of a reaction device for synthesizing dipropylene glycol DETAILED DESCRIPTION

[0012] Raw propylene glycol and raw propylene oxide are preheated to 120℃ and 60℃ respectively, a plate reactor is adopted, cooling water or material is arranged between the plates, raw propylene glycol and raw propylene oxide are fed into the plates, and the two are fed separately to prevent contact reaction on the pipeline and control the heat release, the material is fully mixed by a double helix mixer, the flow channel in the plate is provided with convex eight-shaped or herringbone patterns to make the material fully contact and increase the reaction effect, a liquid catalyst is mixed with raw propylene glycol and then fed in, or a solid catalyst is fixed in the plate, the length of the flow channel in the plate is designed to satisfy the residence time of more than 10 minutes to ensure complete reaction.

[0013] Raw propylene glycol and raw propylene oxide are fed according to the molar ratio of 2:1, the reaction temperature is controlled to be 80℃, the pressure is controlled to be 0.6 MPaG, the feeding time is one hour, the outlet material composition is analyzed, sample 1; the temperature is adjusted to 100℃, the feeding time is one hour, the outlet material composition is analyzed, sample 2; the temperature is adjusted to 120℃, the feeding time is one hour, the outlet material composition is analyzed, sample 3; the reaction temperature is adjusted back to 100℃, the reaction pressure is adjusted to 0.8 MPaG, the feeding time is one hour, the outlet material composition is analyzed, sample 4; the reaction pressure is adjusted to 1.0 MPaG, the feeding time is one hour, the outlet material composition is analyzed, sample 5; the reaction pressure is adjusted to 1.2 MPaG, the feeding time is one hour, the outlet material composition is analyzed, sample 6.

[0014] The experimental data are arranged as follows:

[0015]

[0016] From the experimental data, it can be seen that the use of plate reactor increases the PO conversion rate while reducing the by-product tripropylene glycol generation. The higher the reaction temperature, the higher the PO conversion rate, and the higher the by-product tripropylene glycol content. The higher the reaction pressure, the higher the PO conversion rate, and the higher the by-product tripropylene glycol content.

Claims

1. A reaction device for synthesizing dipropylene glycol, using a plate reactor, with cooling water or material between the plates and raw materials of propylene glycol and propylene oxide entering the plates, characterized in that: Two feed streams enter the plate separately, and a double helix mixer is arranged, the plate channel is provided with convex eight-shaped or herringbone pattern, the plate channel width is 1cm-5cm, and the plate channel length satisfies the material residence time of 10 minutes. ​ 2. The reaction device for synthesizing dipropylene glycol according to claim 1, characterized by: The The propylene glycol and propylene oxide feed ratio is 1:1-3:1 (molar ratio).

3. The reaction device for synthesizing dipropylene glycol according to claim 1, characterized in that: The reaction pressure is controlled at 0-2 MpaG.

4. The reaction device for synthesizing dipropylene glycol according to claim 1, characterized in that: The reaction temperature is controlled at 60-180°C.

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