Preparation method for high-purity methylal

A methylal, high-purity technology, applied in the field of high-purity methylal preparation, can solve problems such as excessive formaldehyde and methanol, not mentioned in the process flow and implementation cases, affecting the reaction effect of the reactive distillation tower, etc., to achieve reduction Formaldehyde content, the effect of improving material utilization

Inactive Publication Date: 2012-04-18
CHINA NAT OFFSHORE OIL CORP +1
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Problems solved by technology

The disadvantage of this method is that the system introduces new impurities, and the purity of the obtained methylal can only reach 99.8%.
[0005] Patent CN101597117A proposes a high-concentration methylal pressurized rectification preparation device, but this patent focuses on the structure of the equipment, and does not mention the specific process flow and implementation cases
And the patent is a two-tower process. The methanol-rich methylal mixture extracted from the top of the pressurized tower is returned to the reactive distillation column for recycling. The disadvantage of this process is that the methanol-rich methylal mixture is directly returned to the reactive distillation column. The tower is recycled, so the fluctuation of the composition will directly affect the reaction effect of the reactive distillation tower, which may seriously exceed the standard of formaldehyde and methanol in the wastewater discharged from the tower bottom

Method used

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  • Preparation method for high-purity methylal
  • Preparation method for high-purity methylal

Examples

Experimental program
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Effect test

Embodiment 1

[0022] Reactive distillation tower T1: formaldehyde solution (1) is the formaldehyde aqueous solution that mass concentration is 8.66%, and feed rate is 420 kg / hour, and methanol raw material (2) feed rate is 82 kg / hour, and mass concentration is 99.5%, The number of rectification trays is 40, the position of the formaldehyde feed plate is at the 10th, and the position of the methanol feed plate is at the 30th. The catalyst strong acidic cation exchange resin is placed in the packed tower in the form of a catalyst package, and the reflux ratio is controlled at 3, the methylal that tower top obtains and the azeotrope (3) of methyl alcohol add up to 100 kilograms / hour, form 92.1% methylal, 7.8% methyl alcohol, 720ppm water, material 3 enters T2 tower, tower still discharges waste water ( 4) The formaldehyde content in the medium is 148ppm.

[0023] Pressurized distillation tower (T2): The operating pressure is 1.2Mpa, the number of theoretical plates is 40, the reflux ratio at t...

Embodiment 2

[0026]Reactive distillation tower T1: formaldehyde solution (1) is the formaldehyde aqueous solution that mass concentration is 8.66%, and feed rate is 420 kg / hour, and methanol raw material (2) feed rate is 81.5 kg / hour, and mass concentration is 99.5%, The number of rectification trays is 40, the position of the formaldehyde feed plate is at the 10th, and the position of the methanol feed plate is at the 30th. The catalyst strong acidic cation exchange resin is placed in the packed tower in the form of a catalyst package, and the reflux ratio is controlled at 3, the methylal that tower top obtains and the azeotrope (3) of methyl alcohol add up to 100 kilograms / hour, form 92.1% methylal, 7.8% methyl alcohol, 720ppm water, material 3 enters T2 tower, tower still discharges waste water ( 4) The formaldehyde content in the medium is 148ppm.

[0027] Pressurized rectification tower (T2): The operating pressure is 1.5Mpa, the number of theoretical plates is 40, the reflux ratio at...

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Abstract

The invention provides a preparation method for high-purity methylal. A production technology has the advantage of low formaldehyde emission. According to the production technology, carbinol and formaldehyde are taken as raw materials, and a reaction rectifying technique and a variable pressure difference rectifying technique are used for preparing the high-purity methylal with the purity above 99.9%. The content of the formaldehyde in the discharged waste water is less than 500ppm. According to the whole technological process, the purity of the methylal product is promoted, the recycling use ratio of the materials is increased and the content of the formaldehyde in the waste water is reduced.

Description

Technical field: [0001] The invention relates to the technical field of fine chemicals, and is a method for preparing high-purity methylal; and has the advantages of low formaldehyde emission, especially a method for preparing formaldehyde with a concentration of more than 99.9% by using reactive distillation technology and differential pressure differential distillation technology. Acetal, and the methylal production process in which the formaldehyde content in the wastewater discharged from the bottom of the reaction tower is less than 500ppm. technical background: [0002] Methylal is a colorless transparent liquid with excellent solubility, widely used in cosmetics, medicines, household products, industrial automotive products, insecticides, leather polishes, cleaning agents, rubber industry, paints, inks and other products Among them, it is also an environmentally friendly product that replaces chlorinated solvents and Freon and reduces air pollution. [0003] Japan ha...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C43/30C07C41/56C07C41/58
CPCY02P20/10
Inventor 张健于海斌孙彦民李晓云
Owner CHINA NAT OFFSHORE OIL CORP
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