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Method for preparing p-phenylene diisocyanate by non-phosgene method

A technology of p-phenylene diisocyanate and p-phenylene diamine, which is applied in the field of non-phosgenation preparation of p-phenylene diisocyanate, and achieves the effects of short reaction time, simple product separation and high purity

Pending Publication Date: 2021-12-31
辽宁天彩材料股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Also do not see report to be raw material with p-phenylenediamine and dialkylcarbamoyl chloride, without separating three substituted urea intermediates, directly synthesize p-phenylenediisocyanate (PPDI )

Method used

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  • Method for preparing p-phenylene diisocyanate by non-phosgene method
  • Method for preparing p-phenylene diisocyanate by non-phosgene method
  • Method for preparing p-phenylene diisocyanate by non-phosgene method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0071] A method for preparing p-phenylene diisocyanate by non-phosgene method, using N,N"-(1,4-phenylene)bis(N',N'-diethyl)urea (hereinafter referred to as "p-phenylene diisocyanate) Diamine diethyl urea") is a raw material, methanesulfonic acid is a protonic acid, and adopts a batch tank type reactor to generate p-phenylene diisocyanate by one-step pyrolysis. Specifically,

[0072] Weigh a quantitative amount of p-phenylenediamine diethylurea into a 100ml two-necked flask, add an appropriate amount of solvent (cyclohexane, xylene, trimethylbenzene or n-octane), heat and stir to a given temperature (80-170°C within the range). Then weigh quantitative methylsulfonic acid and add it to the reaction flask, react at a constant temperature (within 1 to 4 hours), observe the reaction phenomenon, and use infrared spectroscopy to track the reaction. -1 The absorption peak of NCO appeared at , indicating the formation of the product. After the reaction liquid is lowered to room tempe...

Embodiment 2

[0082] A method for preparing p-phenylene diisocyanate by non-phosgene method, using N,N"-(1,4-phenylene)bis(N',N'-diisopropyl)urea (hereinafter referred to as "p-phenylene diisocyanate") Phenylene diisopropyl urea ") is raw material, and n-octane is solvent, and methanesulfonic acid is protonic acid, adopts batch still reactor one-step pyrolysis to generate p-phenylene diisocyanate. Experimental procedure is identical with embodiment 1.

[0083] The consumption, reaction conditions and productive rate of reaction raw material, protonic acid and solvent in table 2 embodiment 2

[0084]

[0085] Experimental phenomena and results:

[0086] (1) P-phenylenediisopropylurea is insoluble in n-octane at room temperature, and it will gradually dissolve when heated to 125°C. During the reaction, a colorless viscous liquid is produced at the bottom of the reactor, and the colorless viscous liquid becomes white solid;

[0087] (2) Infrared spectrum tracking reaction, the absorption ...

Embodiment 3

[0091] A method for preparing p-phenylene diisocyanate by non-phosgene method, using N,N"-(1,4-phenylene) bis(N',N'-diisopropyl)urea ("p-phenylene diisopropyl) urea") as raw material, n-octane as solvent, and hydrogen chloride as protonic acid. Weigh quantitative p-phenylenediisopropylurea (2.263g, 6.25mmol), put it into a 100ml two-necked flask at room temperature, add n-octane (50ml), obtain the incompletely dissolved slurry.In the 50ml there-necked flask, ethanol (5.75g, 0.125mol) is loaded into, after feeding nitrogen flow, start to add tetrachlorosilane (5.31g, 31.25mmol) dropwise, will produce The hydrogen chloride gas was passed to the bottom of the above-mentioned 100ml reaction bottle solution, stirred at the same time, and then gradually heated up to 115°C. During the reaction, stratification occurred. After 4 hours of reaction, it was lowered to room temperature, and stood for 2 hours, and a white solid was produced at the bottom. Filtration to obtain the filtrate, ...

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Abstract

The invention discloses a method for preparing p-phenylene diisocyanate by a non-phosgene method, one of the following methods is selected: (a) taking N, N''-(1, 4-phenylene) bis (N', N'-dialkyl) urea and protonic acid as raw materials, and carrying out protonation and pyrolysis to obtain p-phenylene diisocyanate; and (b) taking p-phenylenediamine, dialkyl carbamoyl chloride and an acid-binding agent as raw materials, carrying out nucleophilic substitution reaction to generate N, N''-(1, 4-phenylene) bis (N', N '-dialkyl) urea and ammonium hydrochloride corresponding to the acid-binding agent in situ, and then carrying out protonation and pyrolysis to obtain the p-phenylene diisocyanate. According to the preparation method, p-phenylene diisocyanate is synthesized in one step or continuously by using an intermittent tank reactor or a micro-channel continuous flow reactor under the action of protonic acid. The intermittent and continuous preparation process of the non-phosgene method has the advantages that the reaction time is short, the product is easy to separate, a hydrogen chloride byproduct is not generated and the like, the purity of the product is as high as 98%, and the yield is as high as 97%.

Description

technical field [0001] The invention belongs to the technical field of isocyanate synthesis, and in particular relates to a method for preparing p-phenylene diisocyanate through non-phosgenation. Background technique [0002] P-phenylene diisocyanate (PPDI) is the simplest aromatic diisocyanate. The pure product is white crystal with a melting point of 96-98°C. It is an important raw material for preparing high-performance polyurethane products. The industrial preparation method uses p-phenylenediamine as The raw material is prepared by phosgenation. In addition to using highly toxic gas phosgene, bis-(trichloromethyl)carbonate (solid phosgene) can also be used to replace phosgene and p-phenylenediamine for phosgenation, and the reaction will produce a large amount of hydrogen chloride by-products, such as the Chinese patent The preparation method of PPDI disclosed in CN111747868B, CN1687022, CN103351312A and CN107011215B. Due to the low solubility of p-phenylenediamine, t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C263/06C07C265/14C07C273/18C07C275/40
CPCC07C273/1845C07C263/06C07C275/40C07C265/14
Inventor 王植源
Owner 辽宁天彩材料股份有限公司
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