Composite polymerization inhibitor for extracting and rectifying conjugated diene with dimethylformamide and use method

Abstract

The invention relates to a composite polymerization inhibitor for extracting and rectifying conjugated diene with dimethylformamide, and a use method. The composite polymerization inhibitor is characterized in that the inhibitor comprise a component A and a component B, wherein the component A is a mixed solution prepared by dissolving 4-hydroxyl-2,2,6,6-tetramethyl piperidine-1-oxygen, 2-hydroxyl ethylamine and an adjuvant in toluene; a weight concentration of 4-hydroxyl-2,2,6,6-tetramethyl piperidine-1-oxygen in the mixed solution is 10-20%; a weight concentration of 2-hydroxyl ethylamine in the mixed solution is 20-40%; a weight concentration of the adjuvant in the mixed solution is 5.0-20%; the adjuvant is alcohol, propyl alcohol, isopropanol, isobutanol, tertiary butanol or phenethyl alcohol; and the component B is a sodium nitrite aqueous solution with a weight concentration of 10-30%. The components of the polymerization inhibitor have synergistic effects, the polymerization inhibitor has a good polymerization inhibition effect, is not deposited in a tower, is convenient and accurate to use, is not crystallized and is freeze-resistant in a low temperature environment, and the consumption of a solvent is low.

Description

technical field [0001] The invention relates to the field of polymerization inhibition in the production process of polymer monomers, in particular to an antifreezing and anti-blocking N,N-dimethylformamide composite polymerization inhibitor for extracting and rectifying conjugated diolefins and a use method thereof. Background technique [0002] The cracked carbon five contains isoprene, and the cracked carbon four contains butadiene, and isoprene and butadiene are monomers for making rubber. The extraction and rectification process is usually used to separate the isoprene in the cracked C5 and the butadiene in the cracked C4. Commonly used extraction and distillation solvents include N,N-dimethylformamide (hereinafter referred to as dimethylformamide or DMF), acetonitrile, and N-methylpyrrolidone. Due to the good selectivity of DMF and the high purity of monomers, most processes Using dimethylformamide. [0003] Conjugated dienes such as isoprene and butadiene are very a...

AI Technical Summary

Problems solved by technology

Undissolved sodium nitrite deposits at the solvent feed plate and downcomer, accumulating over time, clogging the tray and downcomer, resulting in flooding and reduced processing capacity

On the other hand, sodium nitrite is added intermittently, the content of sodium nitrite in the circulating solvent is high when it is just added, and then decreases, the content of sodium nitrite cannot be effectively controlled, and the polymerization inhibition effect cannot be guaranteed when the content is low

Although this way of adding sodium nitrite has disadvantages such as poor solubility, easy tower blockage, ineffective control of content, and large content fluctuations, due to its unique inhibitory effect, no suitable substitute has been found so far.

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