Method for removing potassium ions in tetramethoxysilane

Abstract

The invention discloses a method for removing potassium ions in tetramethoxysilane. The method comprises the following steps: carrying out adsorption treatment on TMOS by using a molecular sieve and aluminum oxide mixed adsorbent; filtering to remove the adsorbent, distilling at normal pressure, and collecting fractions at 120-122 DEG C; adding a complexing agent, carrying out atmospheric distillation again, and collecting fractions at 120-122 DEG C; the molecular sieve is any one of 3A, 4A, 5A and 13X; the aluminum oxide is macroporous aluminum oxide, and the pore volume of the aluminum oxide is gt; the specific surface area is greater than 280m < 2 > / g, and the Na2O content is 1t; 0.05% by weight; the purification process is simple, the used raw materials are easy to obtain, and the method is suitable for industrial large-scale production; the raw material adaptability is high, and a TMOS sample mixed with 1% of metal salts can be purified to be below 10 ppb.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical purification, and particularly relates to a method for removing potassium ions from tetramethoxysilane. Background Art

[0002] Tetramethoxysilane Si(OCH3)4 (TMOS) is a colorless liquid that is easily hydrolyzed. It has a wide range of uses in industrial production and can be used for heat-resistant coatings, chemical-resistant coatings, silica sols, silica aerogels, etc. It also has very good application prospects in ultra-pure powder materials, and its market demand is gradually increasing. When using silicon dioxide as a raw material to prepare TMOS, a catalyst containing potassium ions, such as KOH, is often used, which will result in a higher content of potassium ions in the resulting product. When used in the preparation of ultra-pure powders, the potassium ions in the raw materials need to be removed. Therefore, it is necessary to develop a method for removing potassium ions from tetramethoxysilane. Summary of the invention

[0003] The object of the present invention is to provide a method for removing potassium ions from tetramethoxysilane, which reduces the metal ions in industrial-grade TMOS raw materials to below 10 ppb by using treatment methods such as adsorption, distillation, and complexation.

[0004] In order to achieve the above purpose, the technical solutions adopted are as follows:

[0005] A method for removing potassium ions from tetramethoxysilane comprises the following steps:

[0006] (1) Using molecular sieve and alumina mixed adsorbent to adsorb TMOS;

[0007] (2) filtering to remove the adsorbent, distilling at atmospheric pressure, and collecting the fraction at 120-122°C;

[0008] (3) Add a complexing agent and perform atmospheric distillation again, and collect the fraction at 120-122°C.

[0009] According to the above scheme, the molecular sieve in step 1 is any one of 3A, 4A, 5A, and 13X.

[0010] According to the above scheme, the alumina in step 1 is macroporous alumina with a pore volume of >1.0 mL / g and a specific surface area of ​​>280 m 2 / g, Na2O content <0.05%.

[0011] According to the above scheme, step 1 is adsorbed at 0-50°C for 5-120 min.

[0012] According to the above scheme, the mass ratio of the molecular sieve, alumina mixed adsorbent and TMOS in step 1 is 1:(10-50).

[0013] According to the above scheme, the mass ratio of molecular sieve to alumina in the mixed adsorbent in step 1 is 1:(1-10).

[0014] According to the above scheme, the complexing agent used in step 3 is one or two of EDTA, citric acid, 18-crown-6, 15-crown-5, or a mixture thereof.

[0015] According to the above scheme, the mass ratio of the complexing agent to TMOS used in step 3 is 1:(50-200).

[0016] According to the above scheme, the fraction obtained in step 3 is further subjected to ion exchange treatment:

[0017] TMOS is passed through the ion exchange column at a temperature of 0 to 40° C. and a rate of 1 to 20 times the bed volume / min.

[0018] According to the above scheme, the ion exchange column uses a gel-type or macroporous strongly acidic cation exchange resin.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention uses a molecular sieve and alumina mixed adsorbent to adsorb metal cations. The molecular sieve has an ion exchange effect, especially a good adsorption effect on high-valent metal ions. However, the molecular sieve has a weak adsorption effect on alkali metal ions, and can have a better adsorption effect on alkali metal ions when combined with a macroporous alumina adsorbent. The reason is that after alumina is added to TOMS, it will adsorb metal ions. The macroporous alumina has more hydroxyl groups on the surface. After potassium ions enter the pores, TMOS will be partially hydrolyzed, blocking the pores, which can fix potassium ions in the pores, while ordinary alumina and molecular sieves are easy to desorb after adsorbing potassium ions.

[0021] The complexing agent added in the present invention can form a complex with the metal ions to prevent escape during distillation.

[0022] The present invention uses ion exchange resin for treatment, which can make the metal ions in the solution stay in the resin through ion exchange, and further reduce the metal ion content in TMOS.

[0023] The purification process of the invention is simple, the raw materials used are easily available, and the invention is suitable for industrialized large-scale production; the raw materials have strong adaptability, and a TMOS sample mixed with 1% of metal salts can be purified to below 10 ppb. DETAILED DESCRIPTION

[0024] The following examples further illustrate the technical solution of the present invention, but are not intended to limit the scope of protection of the present invention.

[0025] A specific embodiment provides a method for removing potassium ions from tetramethoxysilane:

[0026] (1) Using a molecular sieve and alumina mixed adsorbent to adsorb TMOS at 0-50°C for 5-120 min; the molecular sieve is any one of 3A, 4A, 5A, and 13X; the alumina is macroporous alumina with a pore volume of >1.0 mL / g and a specific surface area of ​​>280 m 2 / g, Na2O content <0.05%;

[0027] (2) filtering to remove the adsorbent, distilling at atmospheric pressure, and collecting the fraction at 120-122°C;

[0028] (3) adding a complexing agent and performing atmospheric distillation again, collecting the fraction at 120-122° C.;

[0029] (4) Passing the fraction obtained in step 3 through an ion exchange column at a temperature of 0 to 40° C. and a rate of 1 to 20 times the bed volume / min.

[0030] Specifically, the mass ratio of molecular sieve, alumina mixed adsorbent and TMOS is 1:(10-50); the mass ratio of molecular sieve and alumina mixed adsorbent is 1:(1-10).

[0031] Specifically, the complexing agent used is one or two of EDTA, citric acid, 18-crown-6, 15-crown-5, or a mixture thereof; the mass ratio of the complexing agent to TMOS is 1:(50-200).

[0032] Specifically, the ion exchange column uses a gel-type or macroporous strongly acidic cation exchange resin.

[0033] Example 1

[0034] 150 g of TMOS was processed as follows:

[0035] Step 1: Add 3 g of 3A molecular sieve and 3 g of alumina mixed adsorbent to TMOS and adsorb for 120 min at 0°C;

[0036] Step 2: Filter, perform simple distillation at normal pressure, and collect the fraction at 120-122°C;

[0037] Step 3: Add 0.75 g of 15-crown ether-5 to the TMOS collected in step 2, perform simple distillation again, and collect the fraction at 120-122° C.

[0038] The obtained product was analyzed by ICP-MS, and the potassium ion content was 5.5 ppb.

[0039] Example 2

[0040] 150 g of TMOS was processed as follows:

[0041] Step 1: Add 5 g of 4A molecular sieve and 50 g of alumina mixed adsorbent to TMOS and adsorb at 20°C for 60 min;

[0042] Step 2: Filter, perform simple distillation at normal pressure, and collect the fraction at 120-122°C;

[0043] Step 3, adding 1.5 g of 15-crown ether-5 to the TMOS collected in step 2, performing simple distillation again, and collecting the fraction at 120-122° C.;

[0044] Step 4: The fraction collected in step 3 is passed through an ion exchange column at a temperature of 20° C. and a rate of 10 times the bed volume / min.

[0045] The obtained product was analyzed by ICP-MS, and the potassium ion content was 3.5 ppb.

[0046] Example 3

[0047] 150 g of TMOS was processed as follows:

[0048] Step 1: Add 15 g of 5A molecular sieve, 45 g of alumina and a mixed adsorbent to TMOS, and adsorb at 40°C for 60 min;

[0049] Step 2: Filter, perform simple distillation at normal pressure, and collect the fraction at 120-122°C;

[0050] Step 3, adding 1.5 g of 18-crown ether-6 to the TMOS collected in step 2, performing simple distillation again, and collecting the fraction at 120-122° C.;

[0051] Step 4: The fraction collected in step 3 is passed through an ion exchange column at a temperature of 10° C. and a rate of 15 times the bed volume / min.

[0052] The obtained product was analyzed by ICP-MS, and the potassium ion content was 1.8 ppb.

[0053] Example 4

[0054] 150 g of TMOS was processed as follows:

[0055] Step 1: Add 15 g of 13X molecular sieve and 60 g of alumina mixed adsorbent to TMOS and adsorb at 50°C for 5 min;

[0056] Step 2: Filter, perform simple distillation at normal pressure, and collect the fraction at 120-122°C;

[0057] Step 3, adding 3 g of 18-crown ether-6 to the TMOS collected in step 2, performing simple distillation again, and collecting the fraction at 120-122° C.;

[0058] Step 4: The fraction collected in step 3 is passed through an ion exchange column at a temperature of 30° C. and a rate of 5 times the bed volume / min.

[0059] The obtained product was analyzed by ICP-MS, and the potassium ion content was 1.5 ppb.

[0060] Example 5

[0061] 150 g of TMOS was processed as follows:

[0062] Step 1: Add 15 g of aluminum oxide to TMOS and adsorb at 30°C for 15 min;

[0063] Step 2: Filter, perform simple distillation at normal pressure, and collect the fraction at 120-122°C;

[0064] Step 3, adding 3 g of 18-crown ether-6 to the TMOS collected in step 2, performing simple distillation again, and collecting the fraction at 120-122° C.;

[0065] Step 4: The fraction collected in step 3 is passed through an ion exchange column at a temperature of 20° C. and a rate of 10 times the bed volume / min.

[0066] The obtained product was analyzed by ICP-MS, and the potassium ion content was 1.7 ppb.

[0067] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A method for removing potassium ions from tetramethoxysilane, characterized in that The following steps are involved: (1) Using molecular sieve and alumina mixed adsorbent to adsorb TMOS; (2) filtering to remove the adsorbent, distilling at atmospheric pressure, and collecting the fraction at 120-122°C; (3) Add a complexing agent and perform atmospheric distillation again, and collect the fraction at 120-122°C.

2. The method for removing potassium ions from tetramethoxysilane as claimed in claim 1, characterized in that The molecular sieve in step 1 is any one of 3A, 4A, 5A, and 13X.

3. The method for removing potassium ions from tetramethoxysilane as claimed in claim 1, characterized in that The alumina in step 1 is macroporous alumina with a pore volume of >1.0 mL / g and a specific surface area of ​​>280 m 2 / g, Na2O content <0.05%.

4. The method for removing potassium ions from tetramethoxysilane as claimed in claim 1, characterized in that Step 1: adsorb at 0-50°C for 5-120 minutes.

5. The method for removing potassium ions from tetramethoxysilane as claimed in claim 1, characterized in that Step 1: The mass ratio of the molecular sieve, alumina mixed adsorbent and TMOS is 1: (10-50).

6. The method for removing potassium ions from tetramethoxysilane as claimed in claim 1, characterized in that The mass ratio of molecular sieve to alumina in the mixed adsorbent of step 1 is 1:(1-10).

7. The method for removing potassium ions from tetramethoxysilane as claimed in claim 1, characterized in that The complexing agent used in step 3 is one or two of EDTA, citric acid, 18-crown-6, 15-crown-5, or a mixture thereof.

8. The method for removing potassium ions from tetramethoxysilane as claimed in claim 1, characterized in that In step 3, the mass ratio of the complexing agent to TMOS is 1:(50-200).

9. The method for removing potassium ions from tetramethoxysilane as claimed in claim 1, characterized in that The step further comprises subjecting the fraction obtained in step 3 to ion exchange treatment: TMOS is passed through the ion exchange column at a temperature of 0 to 40° C. and a rate of 1 to 20 times the bed volume / min.

10. The method for removing potassium ions from tetramethoxysilane as claimed in claim 9, characterized in that The ion exchange column adopts gel type or macroporous strong acid cation exchange resin.