Preparation device and preparation method of 3-methylmercapto propionaldehyde

Abstract

The invention relates to a preparation device and a preparation method of 3-methylmercapto propionaldehyde. The preparation device is provided with a reaction kettle, washing tanks, a washing circulating pump, absorbing kettles, an absorbing circulating pump, a separating device and a vacuum pump, wherein a methanthiol outlet of the reaction kettle is connected with methanthiol inlets of the washing tanks, an acrolein solution inlet of the reaction is externally connected with an acrolein solution source, and discharging holes of the washing tanks are connected with the reaction kettle and the washing tanks; and methanthiol outlets of the washing tanks are connected with methanthiol inlets of the absorbing kettles, acrolein inlets of the absorbing kettles are connected with the acrolein source, discharging holes of the absorbing kettles are communicated with a feeding hole of the absorbing circulating pump, a discharging hole of the absorbing circulating pump is communicated with feeding holes of the absorbing kettles, and 3-methylmercapto propionaldehyde is conveyed to a finished product through discharging holes of the absorbing kettles. A first preparation method comprises the steps of adding dimethyl sulfate into a sodium hydrosulfide water solution to obtain methanthiol, washing with cooling water, and reacting methanthiol with acraldehyde liquid, so as to obtain 3-methylmercapto propionaldehyde. A second preparation method comprises the steps of adding sulfuric acid into a sodium methyl mercaptide solution to obtain methanthiol gas, washing, cooling, and reacting methanthiol gas with acrolein, so as to obtain 3-methylmercapto propionaldehyde.

Description

technical field [0001] The invention relates to 3-methylthiopropanal, in particular to a 3-methylthiopropanal preparation device and a preparation method thereof. Background technique [0002] 3-Methylthiopropionaldehyde is a common intermediate for the preparation of methionine and methionine's hydroxyl analog, 2-hydroxy-4-methylthiobutanoic acid. Methionine is an essential amino acid in animal feed compositions, and the hydroxyl analogs of methionine are sources of methionine, which are widely used as methionine supplements in animal feed. [0003] 3-Methylthiopropanal can be prepared by Michael addition reaction of methyl mercaptan and acrolein under the action of catalyst. One of the conventional preparation methods is to introduce liquid methyl mercaptan and liquid acrolein into a reactor containing liquid-phase 3-methylthiopropionaldehyde and an organic base as a catalyst for the olefin / mercaptan addition reaction, so that the reaction occurs in the liquid phase. con...

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Problems solved by technology

However, in the actual production process of this method, due to the liquid-liquid reaction, the reaction speed is fast and the reaction is exothermic, and the local concentration of methyl mercaptan or acrolein is too high and / or local overheating easily leads to the generation of by-products, thereby reducing Purity and yield of 3-methylthiopropanal product

At the same time, under normal temperature and pressure, methyl mercaptan appears as a gas, which is toxic and has a pungent taste. To turn it into a liquid, it must be pressurized and cooled, which consumes a lot of energy and greatly increases the cost.

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