- METHOD FOR PRODUCING DIOL HAVING CYCLIC ACETAL SKELETON
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The present invention provides a method for producing a diol having a cyclic acetal skeleton, in which the method include an acetalization reaction step of obtaining a diol having a cyclic acetal skeleton by subjecting raw material hydroxypivalaldehyde and at least pentaerythritol and/or trimethylolpropane to an acetalization reaction under an acid catalyst and the raw material hydroxypivalaldehyde can contain a prescribed amount of at least one impurity selected from the group consisting of formaldehyde, neopentyl glycol, an ester compound having a neopentyl glycol skeleton represented by formula (III), and isobutyraldehyde.
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Paragraph 0158; 0159; 0160; 0161; 0162-0173
(2019/02/28)
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- Preparation method of spiroglycol
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The invention relates to a chemical industry field and particularly relates to a preparation method of spiroglycol. The preparation method includes steps of compounding 2, 2-dimethyl-3-hydroxy-propionaldehyde; adding formaldehyde solution in a four-opening bottle; controlling temperature at 20 DEG C below; adding potassium carbonate in batches, dissolving the system transparently, and rising temperature to 45 DEG C; starting to drop isobutyraldehyde; after reaction, neutralizing and filtering, drying to obtain 2, 2- dimethyl-3-hydroxy-propionaldehyde; compounding volution ethylene glycol; adding 1, 2- dichloroethane in a four-opening flask with a mixer and a thermometer; then adding 2-methyl-2-hydroxymethyl propionaldehyde and pentaerythritol; when temperature is risen to 75 DEG C, completely dissolving the system and adding catalyst. The preparation method is simple in technical flow, safe in reaction and avoids the generation of a lot of waste water; besides, the reaction is carriedout in a homogeneous phase, the product purity and yield are improved, the production cost is reduced, and the production efficiency and product quality are improved.
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Paragraph 0013
(2018/07/30)
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- PROCESS FOR PRODUCTION OF A SPIROGLYCOL
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Disclosed is a process for production of a spiroglycol by subjecting pentaerythritol to reaction in water with hydroxypivaldehyde in presence of a catalytically active amount of at least one acid catalyst and seed particles, wherein pentaerythritol, water, at least one acid catalyst and spiroglycol seed particles are charged to a reaction vessel, equipped with heating/cooling and agitation, and under stirring heated to a predetermined reaction temperature followed by progressive addition of hydroxypivaldehyde. The spiroglycol seed particles are present in an amount of 0.5-1.0% by weight, calculated on pentaerythritol, water, acid catalyst and hydroxypivaldehyde, and the hydroxypivaldehyde is charged at a rate determined over time by monitoring growth and/or formation of yielded spiroglycol particles.
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Page/Page column 3
(2017/01/09)
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- Process for the production of the spiroglycol 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane
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In the production of spiroglycol by the reaction of pentaerythritol and hydroxypivalaldehyde in water in the presence of an acid catalyst, (A) a total content of amines and amine salts in hydroxypivalaldehyde is reduced to 1.5% by weight or lower; (B) seed crystals are added to the reaction system before initiating the reaction and/or during the reaction in an amount from 1.5 to 30% by weight on the basis of the total feed amount of pentaerythritol, hydroxypivalaldehyde, water, the acid catalyst and the seed crystals, each being fed into the reaction system; (C) the pH of the reaction system is kept from 0.1 to 4.0 from initiation of the reaction to completion of the reaction; and (D) the sum of a maximum theoretical amount of spiroglycol to be synthesized from pentaerythritol and hydroxypivalaldehyde to be fed into the reaction system and an amount of spiroglycol contained in the seed crystals to be added to the reaction system is controlled within a range from 5 to 35% by weight on the basis of the total feed amount. The spiroglycol produced has an increased particle size. By washing the spiroglycol with a basic solution, the heat stability is improved.
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Page/Page column 8
(2008/06/13)
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