Method for preparing stable dihydroxypropyl hydroxylamine solution

Abstract

The invention discloses a method for preparing a stable dihydroxypropyl hydroxylamine solution, and relates to the technical field of chemical engineering, and the method comprises the following steps: (1) preparing a solution A: mixing water, hydroxylamine salt and epoxypropane, stirring and dissolving; (2) preparing a solution B: adding alkali into water to prepare alkali liquor; (3) adding the solution B into the solution A, and reacting until the content of hydroxylamine is less than 1%; and (4) adding a stabilizer into the mixed solution obtained by the reaction in the step (3), and uniformly mixing to obtain a stable dihydroxypropyl hydroxylamine solution, wherein any one of nitrilotriacetic acid, disodium ethylene diamine tetraacetate and 8-hydroxyquinoline is adopted. By adding the stabilizer, the dihydroxypropyl hydroxylamine solution which can be stored stably for more than 6 months can be obtained, and the preparation method is simple in process, rich in raw material source and good in safety.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical industry, and in particular to a method for preparing a stable dihydroxypropylhydroxylamine solution. Background Art

[0002] Bis(hydroxypropyl)hydroxylamine is an important fine chemical, mainly used as a scavenger in water treatment and as a polymerization inhibitor for olefin compounds, especially styrene.

[0003] Currently, regarding the synthesis methods of bishydroxypropylhydroxylamine, the stability of the obtained bishydroxypropylhydroxylamine solutions is poor. For example, Chinese patent CN106957240A discloses a synthesis method of hydroxypropylhydroxylamine, which mainly adopts a two-step preparation method, i.e., firstly, hydroxylamine free base is prepared by using hydroxylamine salt and alkali solution, and then alkylene oxide is added to the above hydroxylamine free base to synthesize hydroxypropylhydroxylamine. However, the bishydroxypropylhydroxylamine solution prepared by this method has poor stability; US6028225 discloses a method for synthesizing bishydroxypropylhydroxylamine by using 50% hydroxylamine free base and propylene oxide as raw materials. This method also has the following defects: (1) the decomposition and explosion safety hazard of hydroxylamine free base, and the intrinsic safety of the process is poor; (2) the use of 50% hydroxylamine free base as a raw material has the disadvantages of few suppliers and high price; (3) the product yield and stability are also not mentioned.

[0004] Therefore, providing a stable dihydroxypropylhydroxylamine solution and a preparation method thereof is a technical problem that needs to be solved urgently in the art. Summary of the Invention

[0005] In view of this, the present invention provides a method for preparing a stable bishydroxypropylhydroxylamine solution, which comprises first preparing hydroxylamine free base using hydroxylamine sulfate and potassium hydroxide solution, then adding propylene oxide to synthesize bishydroxypropylhydroxylamine, then heating to recover propylene oxide and filtering out potassium sulfate at low temperature, and simultaneously adding a stabilizer, thereby obtaining a bishydroxypropylhydroxylamine solution that is stable in storage for more than 6 months.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The invention discloses a method for preparing a stable bishydroxypropylhydroxylamine solution, which adopts any one of nitrilotriacetic acid, disodium oxalate tetraacetate and 8-hydroxyquinoline as a stabilizer, preferably nitrilotriacetic acid.

[0008] Preferably, the amount of the stabilizer added is 0.01-5% of the mass of the bishydroxypropylhydroxylamine solution.

[0009] Preferably, the preparation method of the stable bishydroxypropylhydroxylamine solution specifically comprises the following steps:

[0010] (1) Prepare solution A: Mix water, hydroxylamine salt, and propylene oxide and stir to dissolve;

[0011] (2) Preparation of Solution B: Add alkali to water to prepare an alkali solution with a concentration of 10-45%;

[0012] (3) adding the solution B to the solution A to react until the hydroxylamine content is less than 1%;

[0013] (4) After purifying and removing impurities from the mixed solution obtained in step (3), a stabilizer is added and mixed to obtain a stable dihydroxypropylhydroxylamine solution.

[0014] Preferably, the molar ratio of the hydroxylamine salt, the propylene oxide, the base and the water in step (3) is 1:4-6:2-3:0.5-15.5, preferably 1:4-5:2-2.5:10-15.5.

[0015] Preferably, the hydroxylamine salt in step (1) is hydroxylamine sulfate.

[0016] Preferably, the base in step (2) is potassium hydroxide;

[0017] The mass concentration of the alkali solution is 10-45%, preferably 45%.

[0018] The present invention mainly utilizes the low solubility of potassium sulfate, a by-product salt produced by the reaction of hydroxylamine sulfate and potassium hydroxide, to achieve separation from the hydroxylamine solution. Sodium chloride and potassium chloride produced by the reaction of hydroxylamine hydrochloride, sodium hydroxide and potassium hydroxide have relatively large water solubility and high salt content in the final product. The reaction of hydroxylamine sulfate and sodium hydroxide also has the same situation. Therefore, the present invention adopts hydroxylamine sulfate and potassium hydroxide.

[0019] Preferably, the addition in step (3) is carried out dropwise, and the addition time is 0.5-10 hours. The specific time is adjusted according to the heat removal capacity of the reaction equipment. If the heat removal capacity of the reaction equipment is good, the addition time can be appropriately accelerated.

[0020] Preferably, the reaction temperature in step (3) is 0-50°C, preferably 10-35°C.

[0021] Preferably, the purification and impurity removal in step (4) includes recovering the remaining propylene oxide and removing potassium sulfate.

[0022] Preferably, the propylene oxide is recovered by heating to 50-80°C;

[0023] The potassium sulfate is cooled to -10-5°C and then precipitated and removed by filtration.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The preparation method of the present invention has a simple process, abundant raw material sources, good safety, and the product storage stability can be greater than 6 months. DETAILED DESCRIPTION

[0026] The following describes embodiments of the present invention. These embodiments are exemplary and intended to explain the present invention, but are not to be construed as limiting the present invention.

[0027] Example 1

[0028] The present invention provides a method for preparing a stable dihydroxypropylhydroxylamine solution, which specifically comprises the following steps:

[0029] (1) Add 1100 g of water, 650 g of hydroxylamine sulfate and 1500 g of propylene oxide to a 10 L reactor, control the reaction temperature at 15 ° C, and stir to dissolve;

[0030] (2) Prepare a 45% KOH solution by mass, add 990 g of the KOH solution dropwise to the reactor over a period of 3 h. After the addition is complete, keep the temperature at 15°C until the hydroxylamine free base content is less than 1% (potentiometric titration). The reaction time is approximately 6 h.

[0031] (3) After the reaction in step (2) is completed, the temperature is raised to 60°C to recover propylene oxide, then cooled to -5°C for 2 hours, and potassium sulfate is filtered out. The remaining liquid is a colorless and transparent bishydroxypropylhydroxylamine solution with a content of 31.5% (potentiometric titration).

[0032] (4) Then, several 100g portions of the bis(hydroxypropyl)hydroxylamine solution were taken and a certain amount of stabilizer was added. The color and content of the bis(hydroxypropyl)hydroxylamine solution were observed after six and twelve months. The test results are shown in Table 1 below.

[0033] Table 1 Stability results

[0034]

[0035]

[0036] As can be seen from the above table, when no stabilizer is added, the content drops to 28% after 6 months and the solution color turns brown-red; when the stabilizers nitrilotriacetic acid, disodium oxalate tetraacetate and 8-hydroxyquinoline are added, the content of bishydroxypropyl hydroxylamine decreases more slowly, and the color of bishydroxypropyl hydroxylamine after 6 months is basically colorless; however, when the bishydroxypropyl hydroxylamine solution is placed for 12 months, the color of the bishydroxypropyl hydroxylamine solution can still remain unchanged when nitrilotriacetic acid is used as a stabilizer, while the color of the bishydroxypropyl hydroxylamine solution turns yellow when disodium oxalate tetraacetate and 8-hydroxyquinoline are used; when thiourea is added as a stabilizer, the solution turns orange after 6 months and the bishydroxypropyl content drops to 28.5%.

[0037] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing a stable bishydroxypropylhydroxylamine solution, characterized in that: Any one of nitrilotriacetic acid, disodium oxalate tetraacetate and 8-hydroxyquinoline is used as a stabilizer.

2. The method for preparing a stable bishydroxypropylhydroxylamine solution according to claim 1, characterized in that: The amount of the stabilizer added is 0.01-5% of the mass of the dihydroxypropylhydroxylamine solution.

3. The method for preparing a stable bishydroxypropylhydroxylamine solution according to claim 1, characterized in that: The preparation method of the stable dihydroxypropylhydroxylamine solution specifically comprises the following steps: (1) Prepare solution A: Mix water, hydroxylamine salt, and propylene oxide and stir to dissolve; (2) Prepare solution B: Add alkali to water to make lye; (3) adding the solution B to the solution A to react until the hydroxylamine content is less than 1%; (4) Purifying and removing impurities from the mixed solution obtained in step (3) to obtain a dihydroxypropylhydroxylamine solution, and adding a stabilizer and mixing to obtain a stable dihydroxypropylhydroxylamine solution.

4. The method for preparing a stable bishydroxypropylhydroxylamine solution according to claim 1, characterized in that: The molar ratio of the hydroxylamine salt, the propylene oxide, the base and the water in step (1) is 1:4-6:2-3:0.5-15.

5.

5. The method for preparing a stable bishydroxypropylhydroxylamine solution according to claim 1, characterized in that: The hydroxylamine salt in step (1) is hydroxylamine sulfate.

6. The method for preparing a stable bishydroxypropylhydroxylamine solution according to claim 1, characterized in that: The base in step (2) is potassium hydroxide; The mass concentration of the alkali solution is 10-45%.

7. The method for preparing a stable bishydroxypropylhydroxylamine solution according to claim 1, characterized in that: The addition in step (3) is carried out dropwise, and the addition time is 0.5-10h.

8. The method for preparing a stable bishydroxypropylhydroxylamine solution according to claim 1, characterized in that: The reaction temperature in step (3) is 0-50°C.

9. The method for preparing a stable bishydroxypropylhydroxylamine solution according to claim 1, characterized in that: The purification and impurity removal in step (4) includes recovering the remaining propylene oxide and removing potassium sulfate.

10. The method for preparing a stable bishydroxypropylhydroxylamine solution according to claim 7, characterized in that: The propylene oxide is recovered by heating to 50-80°C; The potassium sulfate is cooled to -10-5°C and then precipitated and removed by filtration.

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