1,3-Butanediol is a colorless, slightly bitter-sweet viscous liquid. Melting point -77℃. Boiling point 207.5℃. Relative density 1.0043. Viscosity (25℃) 103.9mPa.s. Refractive index 1.4401. Surface tension (25℃) 37.8mN/m. It is understood that it is soluble in water, acetone, methyl-ethyl (methyl) ketone, ethanol, dibutyl phthalate, castor oil, and almost insoluble in aliphatic hydrocarbons, benzene, toluene, carbon tetrachloride, and ethanolamine Class, mineral oil, linseed oil. It dissolves nylon when heated and also partially dissolves shellac and rosin. Because of its high boiling point, it is easily oxidized by air during distillation under normal pressure, so it is better to distill under reduced pressure. Highly hygroscopic.
A production method of 1,3-butanediol, including the following process steps:
1) Prins condensation reaction: using propylene and formaldehyde aqueous solution As raw material, control the reaction temperature at 20~200℃ and the reaction pressure at 0~10MPa. Through the fixed bed reactor A equipped with an acidic solid catalyst, the reaction generates 1,3-butanediol, tetrahydropyran-4-ol and 4-methyl-1,3-dioxane; the concentration of the reactant formaldehyde aqueous solution is 5 to 70% Chemicalbook; the molar feed ratio of the reactants propylene and formaldehyde is 20:1 to 1:20; the reaction place The formaldehyde feed space velocity per unit volume of the catalyst is: 0.1~1000ml·min-1·LCat.-1; the acidic solid catalyst for the reaction is non-transition element oxide or mixed oxide, zeolite molecular sieve, heteropoly acid, cation One or several mixtures of exchange resins, etc.
(2) Intermediate product separation: The reaction mixture is decompressed and then distilled to separate the unreacted propylene and formaldehyde and re-enter reactor A to continue the reaction.
(3) Hydrolysis reaction: Mix the tetrahydropyran-4-ol and 4-methyl-1,3-dioxane obtained after separation with methanol, and control the reaction temperature at 20~ 200℃, enter the fixed bed reactor B equipped with an acidic catalyst for hydrolysis reaction to obtain 1,3-butanediol and methylal; tetrahydropyran-4-ol and 4-methyl-1,3-dioxa The molar ratio of the sum of cyclohexane Chemicalbook alkanes and methanol is: 1:1~1:30; the feed space velocity per unit volume of the catalyst in the reaction is: 0.1~2000ml·min-1·LCat.-1; the acidity in the reaction is The solid catalyst is one or a mixture of non-transition element oxides or mixed oxides, zeolite molecular sieves, heteropolyacids, cation exchange resins, etc.
(4) Product distillation: The above reaction mixture is rectified to obtain methylal, excess methanol and 1,3-butanediol products respectively, of which the excess methanol is returned to reactor B Keep reacting
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