Electronic-grade high-purity o-chlorophenol crystal material and preparation method thereof

Abstract

The invention discloses an electronic-grade high-purity o-chlorophenol crystal material and a preparation method thereof. The preparation method comprises the following steps: firstly, constructing a two-phase system by adopting a deep eutectic solvent, and removing metal ions and polar organic matters through electromigration; then enabling the pretreated product to pass through a porous organic polymer adsorption column, and selectively removing a color developing component and a fluorescent substance; performing multi-stage zone-melting purification in a protective atmosphere, and realizing efficient purification of the body material by utilizing an impurity segregation effect; and finally, carrying out directional crystallization and annealing treatment to obtain the single crystal material with a complete structure. Through multistage purification and crystal growth, the final product reaches the electronic grade standard that the content of metal impurities is lower than 10 ppb and the total amount of organic impurities is smaller than 1 ppm, and meanwhile, the final product has excellent light transmittance, narrow melting range and extremely low crystal defect density; and the ultrahigh standard requirements of high-end electronic applications such as semiconductor manufacturing and the like on key chemical materials are completely met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic chemicals, in particular to an electronic-grade high-purity o-chlorophenol crystal material and a preparation method thereof. BACKGROUND

[0002] O-chlorophenol is a kind of key intermediate widely used in the fields of fine chemical industry, resin monomer, electronic chemicals and photoetching material, etc. The electronic-grade o-chlorophenol is highly sensitive to metal ions, colored impurities and trace organic by-products, and the purity thereof directly affects the dielectric properties, optical stability and ion contamination level of materials such as photoresist, special resin and electronic cleaning agent. With the semiconductor manufacturing process continuously tending to higher integration and lower defect requirements, the purity of o-chlorophenol is required to be controlled to the order of ten millionth or even lower, and at the same time, the color, fluorescence background and trace impurities such as complex polycyclic aromatic hydrocarbons are required to be reduced to near the detection limit level.

[0003] At present, the purification methods of o-chlorophenol mainly include traditional processes such as vacuum rectification, acid washing and water washing, activated carbon decolorization and multiple recrystallization. The above methods can reduce part of impurities in general chemical-grade products, but there are still obvious deficiencies for electronic-grade products: the removal ability of impurities with close or azeotropic boiling points is limited, acid washing and water washing are easy to introduce new anion impurities, activated carbon decolorization has poor adsorption selectivity for dark or fluorescent impurities, multiple recrystallization process is difficult to remove strong polarity or difficult to volatilize polycyclic aromatic hydrocarbons, and these methods generally cannot effectively reduce the content of metal ions. In addition, the traditional processes have poor batch stability, high energy consumption and unpredictable impurity residues, which are difficult to meet the requirements of electronic manufacturing field on the consistency of crystal structure and uniformity of impurity distribution, especially not suitable for preparing crystal materials with controllable crystal form and extremely low internal defects. Therefore, it is urgent to develop a new purification and crystal growth method with higher structure and selectivity, which can realize ultra-deep metal removal and organic impurity removal, for obtaining high-purity o-chlorophenol crystal material meeting the requirements of electronic grade. SUMMARY

[0004] In view of the above problems, the present application provides an electronic-grade high-purity o-chlorophenol crystal material and a preparation method thereof, which realizes ultra-high purity control through a multi-step coordinated refining and crystal growth process.

[0005] The present application can be realized by the following technical scheme:

[0006] Step 1, o-chlorophenol and deep eutectic solvent (DES) are respectively added to the upper and lower layers of an electrolytic cell to form an upper and lower two-phase system, a low-voltage direct current field is applied at 40-50℃, after the electromigration is completed, the upper o-chlorophenol phase is taken, and then water is removed by vacuum to obtain pre-purified o-chlorophenol;

[0007] Step 2, the pre-purified o-chlorophenol is passed through a porous organic polymer adsorption column and continuously flows through a fixed bed at 30-40℃ to obtain refined o-chlorophenol intermediate product;

[0008] Step 3, the refined o-chlorophenol is heated and melted under nitrogen protection, then placed in a zone melting furnace, a temperature gradient is established along the direction of the boat body, the solid-liquid interface is moved forward by moving the heating zone, and the residual trace impurities are pushed to the end along the melt direction, and the zone melting is repeated and the impurity-enriched segment of 5-10% at the end is cut off to obtain high-purity o-chlorophenol solid;

[0009] Step 4, the high-purity o-chlorophenol melt after zone melting is subjected to directional crystal growth under the guidance of seeding, and the obtained crystal is subjected to annealing treatment, purity detection and crystal type screening, and the product meeting the electronic grade standard is packaged in a nitrogen atmosphere to finally obtain electronic grade high-purity o-chlorophenol crystal material.

[0010] Preferably, in step 1, the weight parts of o-chlorophenol and deep eutectic solvent (DES) are 100 parts and (50-80) parts, respectively.

[0011] Preferably, the preparation method of the deep eutectic solvent (DES) is as follows: choline chloride, tartaric acid and tris(hydroxymethyl)aminomethane are placed in a vacuum drying box according to a molar ratio of 1:(0.8-1.2):(0.1-0.3), then added into a flask, stirred at 60-70℃, then kept at 55-60℃, and nitrogen is introduced for 20-30 min, and then filtered to obtain the deep eutectic solvent (DES).

[0012] Preferably, the construction method of the porous organic polymer adsorption column in step 2 is as follows: 2,4,6-trichloro-1,3,5-triazine, 4-aminophenol and p-diaminostilbene are cross-linked and condensed to form a porous organic polymer adsorbent (POP-OCP-1) according to a molar ratio of 1:(0.8-1.5):(0.05-0.25), the POP-OCP-1 particles are packed in a stainless steel column, the packing density is 0.48-0.52 g / mL, high-purity nitrogen is blown for 1-1.5 h, and the column is activated at 100-120℃ for 4-5 h.

[0013] Preferably, in step 2, the flow rate of o-chlorophenol is 0.5-1.0 BV / h, and the outlet impurity monitoring uses a combination of color, fluorescence and GC-MS monitoring control.

[0014] Preferably, in step 3, the temperature gradient is 10-20 K / cm, and the moving speed of the heating zone is 0.2-0.5 mm / min.

[0015] Preferably, in step 4, the directional crystal growth uses a cooling rate of 0.1-0.2 ℃ / h, and the annealing time is 12-24 h.

[0016] Preferably, the metal impurity content in the final o-chlorophenol crystal material obtained in step 4 is less than 10 ppb, and the total content of organic impurities is less than 1 ppm.

[0017] The beneficial effects of the present application are:

[0018] The core point of the present application is to construct a four-stage synergistic purification mechanism. First, the deep eutectic solvent (DES) is used to realize the deep separation of metal ions and polar impurities under the action of electric field. Then, the synthesized porous organic polymer adsorbent is used to selectively capture colored bodies and fluorescent molecules based on its precise pore size structure and surface functional groups. Then, the multi-stage zone melting technology is used to realize the directional condensation of impurities at the microscale by using the solid-liquid equilibrium principle. Finally, single crystal materials with high crystal lattice integrity are obtained by directional crystallization. This systematic scheme breaks through the limitations of traditional processes, so that the final product meets the electronic grade standard of metal impurity content less than 10 ppb and total organic impurity content less than 1 ppm, while having excellent crystal integrity and optical performance, providing reliable raw material guarantee for high-end electronic chemicals. BRIEF DESCRIPTION OF DRAWINGS

[0019] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, together with the embodiments of the present application, to explain the present application, and do not constitute a limitation on the present application. In the drawings:

[0020] Figure 1 The total metal and total organic impurity content of the crystal material;

[0021] Figure 2 The color and melting range of the crystal material;

[0022] Figure 3 The defect density and fluorescence background intensity of the crystal material. DETAILED DESCRIPTION

[0023] The embodiments of the present application are described in detail as follows: The present embodiments are implemented on the premise of the technical solutions of the present application, and detailed implementation methods and processes are given, but the protection scope of the present application is not limited to the following embodiments. The experimental methods not specified in the following embodiments are usually carried out under conventional conditions.

[0024] Example 1

[0025] The preparation method of an electronic grade high-purity o-chlorophenol crystal material in this embodiment includes the following steps:

[0026] Step 1, 0.1 mol of choline chloride, 0.08 mol of tartaric acid, and 0.01 mol of tris-hydroxymethyl aminomethane were placed in a vacuum drying oven for drying, then added to a flask, stirred at 60°C, then kept at 55°C, nitrogen was introduced for 20 min, filtered, and a deep eutectic solvent (DES) was obtained;

[0027] Step 2, 100 parts of o-chlorophenol and 50 parts of DES were added to the upper and lower layers of an electrolytic cell respectively to form a two-phase system, a low-voltage direct current electric field was applied at 40°C, after the electromigration was completed, the upper o-chlorophenol phase was taken out, and then dehydrated under reduced pressure to obtain pre-purified o-chlorophenol;

[0028] Step 3, 2 mol of 2,4,6-trichloro-1,3,5-triazine, 1.6 mol of 4-aminophenol, and 0.1 mol of p-diaminostilbene were cross-linked and condensed to form a porous organic polymer adsorbent (POP-OCP-1), the POP-OCP-1 particles were packed in a stainless steel column with a packing density of 0.48 g / mL, purged with high-purity nitrogen for 1 h, and activated at 100°C for 4 h to obtain a porous organic polymer adsorption column;

[0029] Step 4, the pre-purified o-chlorophenol was passed through the porous organic polymer adsorption column at a flow rate of 0.5 BV / h under the condition of 30°C, and the outlet impurities were monitored and controlled using a combination of color, fluorescence, and GC-MS to obtain refined o-chlorophenol intermediates;

[0030] Step 5, the refined o-chlorophenol was heated and melted under nitrogen protection, then placed in a zone melting furnace, a temperature gradient of 10 K / cm was established along the direction of the boat body, the solid-liquid interface was moved forward by moving the heating zone at a moving speed of 0.2 mm / min, and the residual trace impurities were pushed to the end along the melt direction, the zone melting was repeated and the impurity-enriched segment of 5% at the end was cut off to obtain high-purity o-chlorophenol solid;

[0031] Step 6, the high-purity o-chlorophenol melt after zone melting was subjected to directional crystal growth at a cooling rate of 0.1°C / h under the guidance of seeding, the obtained crystal was annealed for 12 h, then subjected to purity detection and crystal type screening, the product meeting the electronic grade standard was packaged in a nitrogen atmosphere, and finally electronic grade high-purity o-chlorophenol crystal material was obtained, the metal impurity content of which was less than 10 ppb, and the total content of organic impurities was less than 1 ppm.

[0032] Example 2

[0033] The preparation method of an electronic grade high-purity o-chlorophenol crystal material in this example includes the following steps:

[0034] Step 1, 0.1 mol of choline chloride, 0.12 mol of tartaric acid, and 0.03 mol of tris-hydroxymethyl aminomethane were placed in a vacuum drying oven for drying, then added to a flask, stirred at 70°C, then kept at 60°C, nitrogen was introduced for 30 min, filtered, and a deep eutectic solvent (DES) was obtained;

[0035] Step 2, 100 parts of o-chlorophenol and 80 parts of DES were added to the upper and lower layers of an electrolytic cell respectively to form a two-phase system, a low-voltage direct current electric field was applied at 50°C, after the electromigration was completed, the upper o-chlorophenol phase was taken out, and then water was removed under reduced pressure to obtain pre-purified o-chlorophenol;

[0036] Step 3, 2 mol of 2,4,6-trichloro-1,3,5-triazine, 3.0 mol of 4-aminophenol, and 0.5 mol of p-diaminostilbene were cross-linked and condensed to form a porous organic polymer adsorbent (POP-OCP-1), the POP-OCP-1 particles were packed in a stainless steel column with a packing density of 0.52 g / mL, purged with high-purity nitrogen for 1.5 h, and activated at 120°C for 5 h to obtain a porous organic polymer adsorption column;

[0037] Step 4, the pre-purified o-chlorophenol was passed through the porous organic polymer adsorption column at a flow rate of 1.0 BV / h under the condition of 40°C, and the outlet impurities were monitored and controlled using a combination of color, fluorescence, and GC-MS to obtain refined o-chlorophenol intermediates;

[0038] Step 5, the refined o-chlorophenol was heated and melted under nitrogen protection, then placed in a zone melting furnace, a temperature gradient of 20 K / cm was established along the direction of the boat body, the solid-liquid interface was moved forward by moving the heating zone at a moving speed of 0.5 mm / min, and the residual trace impurities were pushed to the end along the melt direction, the zone melting was repeated and the impurity-enriched segment of 10% at the end was cut off to obtain high-purity o-chlorophenol solid;

[0039] Step 6, the high-purity o-chlorophenol melt after zone melting was subjected to directional crystal growth at a cooling rate of 0.2°C / h under the guidance of seeding, the obtained crystal was treated by annealing for 24 h, then the purity was detected and the crystal form was screened, the product meeting the electronic grade standard was packaged in a nitrogen atmosphere, and finally electronic grade high-purity o-chlorophenol crystal material was obtained, the content of metal impurities in the material was less than 10 ppb, and the total content of organic impurities was less than 1 ppm.

[0040] Example 3

[0041] The preparation method of an electronic grade high-purity o-chlorophenol crystal material in this example includes the following steps:

[0042] Step 1, 0.1 mol of choline chloride, 0.1 mol of tartaric acid, and 0.02 mol of tris-hydroxymethyl aminomethane were placed in a vacuum drying oven for drying, then added to a flask, stirred at 65°C, then kept at 55°C, and nitrogen was introduced for 25 min, filtered, and a deep eutectic solvent (DES) was obtained;

[0043] Step 2, 100 parts of o-chlorophenol and 65 parts of DES were added to the upper and lower layers of an electrolytic cell respectively to form a two-phase system, a low-voltage direct current electric field was applied at 45°C, and after the electromigration was completed, the upper o-chlorophenol phase was taken out and dehydrated under reduced pressure to obtain pre-purified o-chlorophenol;

[0044] Step 3, 2 mol of 2,4,6-trichloro-1,3,5-triazine, 2.3 mol of 4-aminophenol, and 0.3 mol of p-diaminostilbene were cross-linked and condensed to form a porous organic polymer adsorbent (POP-OCP-1), the POP-OCP-1 particles were packed in a stainless steel column with a packing density of 0.5 g / mL, purged with high-purity nitrogen for 1.5 h, and activated at 110°C for 4.5 h to obtain a porous organic polymer adsorption column;

[0045] Step 4, the pre-purified o-chlorophenol was passed through the porous organic polymer adsorption column at a flow rate of 0.75 BV / h under the condition of 35°C, and the outlet impurities were monitored and controlled using a combination of color, fluorescence, and GC-MS to obtain refined o-chlorophenol intermediates;

[0046] Step 5, the refined o-chlorophenol was heated and melted under nitrogen protection, then placed in a zone melting furnace, a temperature gradient of 15 K / cm was established along the direction of the boat body, the solid-liquid interface was moved forward by moving the heating zone at a moving speed of 0.35 mm / min, and the residual trace impurities were pushed to the end along the melt direction, and the zone melting was repeated and the impurity-enriched segment of 10% at the end was cut off to obtain high-purity o-chlorophenol solid;

[0047] Step 6, the high-purity o-chlorophenol melt after zone melting was subjected to directional crystal growth at a cooling rate of 0.1°C / h under the guidance of seeding, and the obtained crystal was treated by annealing for 18 h, then subjected to purity detection and crystal type screening, the product meeting the electronic grade standard was packaged in a nitrogen atmosphere, and finally electronic grade high-purity o-chlorophenol crystal material was obtained, the metal impurity content of which was less than 10 ppb, and the total content of organic impurities was less than 1 ppm.

[0048] Comparative Example 1: The difference between this comparative example and Example 1 is that no DES is added and no electric field treatment is applied.

[0049] The preparation method of one kind of o-chlorophenol crystal material in the comparative example comprises the following steps:

[0050] Step 1, take 2 mol 2, 4, 6-trichloro-1, 3, 5-triazine, 1.6 mol 4-aminophenol, 0.1 mol p-diaminostilbene cross-linking condensation to form a porous organic polymer adsorbent (POP-OCP-1), the POP-OCP-1 particles are packed in a stainless steel column, the packing density is 0.48 g / mL, and the column is purged with high-purity nitrogen for 1 h and activated at 100 ℃ for 4 h to obtain a porous organic polymer adsorption column;

[0051] Step 2, o-chlorophenol is passed through the porous organic polymer adsorption column at a flow rate of 0.5 BV / h under the condition of 30 ℃ to continuously flow through the fixed bed, and the outlet impurities are monitored and controlled by using chroma, fluorescence and GC-MS combination monitoring to obtain refined o-chlorophenol intermediate product;

[0052] Step 3, the refined o-chlorophenol is heated and melted under nitrogen protection, then placed in a zone melting furnace, a temperature gradient of 10 K / cm is established along the direction of the boat body, the solid-liquid interface is moved forward by moving the heating zone at a moving speed of 0.2 mm / min, and the residual trace impurities are pushed to the end along the melt direction, and the zone melting is repeated and the impurity enrichment section of 5% at the end is cut off to obtain high-purity o-chlorophenol solid;

[0053] Step 4, the melt of the zone-melted high-purity o-chlorophenol is subjected to directional crystal growth at a cooling rate of 0.1 ℃ / h under the guidance of seeding, and the obtained crystal is annealed for 12 h, then subjected to purity detection and crystal form screening, and finally o-chlorophenol crystal material is obtained.

[0054] Comparative Example 2: The difference between this comparative example and Example 1 is that ordinary activated carbon is used instead of POP-OCP-1.

[0055] The preparation method of one kind of o-chlorophenol crystal material in the comparative example comprises the following steps:

[0056] Step 1, 0.1 mol of choline chloride, 0.08 mol of tartaric acid and 0.01 mol of tris-hydroxymethyl aminomethane are dried in a vacuum drying box, then added into a flask, stirred at 60 ℃, then kept at 55 ℃, and nitrogen is introduced for 20 min, and then filtered to obtain a deep eutectic solvent (DES);

[0057] Step 2, 100 parts of o-chlorophenol and 50 parts of DES are added to the upper and lower layers of an electrolytic cell respectively to form a two-phase system, and a low-voltage direct current electric field is applied at 40 ℃, after the electromigration is completed, the upper o-chlorophenol phase is taken out, and then dehydrated under reduced pressure to obtain pre-purified o-chlorophenol;

[0058] Step 3, the pre-purified o-chlorophenol was heated and melted under nitrogen protection, then placed in a zone melting furnace, a temperature gradient of 10 K / cm was established along the boat direction, the solid-liquid interface was moved forward by moving the heating zone at a moving speed of 0.2 mm / min, and the residual trace impurities were pushed to the end along the melt direction, and the zone melting was repeated and the impurity-enriched segment of 5% at the end was cut off to obtain high-purity o-chlorophenol solid;

[0059] Step 4, the high-purity o-chlorophenol melt after zone melting was subjected to directional crystal growth under the guidance of seeding at a cooling rate of 0.1 ℃ / h, and the obtained crystal was annealed for 12 h, then subjected to purity detection and crystal form screening, and finally o-chlorophenol crystal material was obtained.

[0060] Comparative Example 3: The difference between this comparative example and Example 1 is that the multi-stage zone melting is cancelled and only one ordinary recrystallization is performed.

[0061] The preparation method of one kind of o-chlorophenol crystal material in the comparative example comprises the following steps:

[0062] Step 1, 0.1 mol of choline chloride, 0.08 mol of tartaric acid and 0.01 mol of tris-hydroxymethyl aminomethane were placed in a vacuum drying box for drying, then added into a flask, stirred at 60℃, then kept at 55℃, and nitrogen was introduced for 20 min, then filtered to obtain a deep eutectic solvent (DES);

[0063] Step 2, 100 parts of o-chlorophenol and 50 parts of DES were added to the upper and lower layers of an electrolytic cell respectively to form a two-phase system, and a low-voltage direct current electric field was applied at 40℃, after the electromigration was completed, the upper o-chlorophenol phase was taken, and then dehydrated under reduced pressure to obtain pre-purified o-chlorophenol;

[0064] Step 3, 2 mol of 2,4,6-trichloro-1,3,5-triazine, 1.6 mol of 4-aminophenol and 0.1 mol of p-diaminostilbene were cross-linked and condensed to form a porous organic polymer adsorbent (POP-OCP-1), the POP-OCP-1 particles were packed in a stainless steel column, the packing density was 0.48 g / mL, high-purity nitrogen was blown for 1 h, and the column was activated at 100℃ for 4 h to obtain a porous organic polymer adsorption column;

[0065] Step 4, the pre-purified o-chlorophenol was continuously flowed through the fixed bed at a flow rate of 0.5 BV / h at 30℃, and the outlet impurities were monitored and controlled using a combination of color, fluorescence and GC-MS to obtain refined o-chlorophenol intermediate product;

[0066] Step 5, the refined o-chlorophenol was heated and melted under nitrogen protection, and then cooled to obtain high-purity o-chlorophenol solid;

[0067] Step 6, the high-purity o-chlorophenol melt after zone melting is subjected to directional crystal growth under the guidance of seeding at a cooling rate of 0.1 ℃ / h, the obtained crystal is subjected to annealing treatment for 12 h, and then purity detection and crystal type screening are performed, and finally o-chlorophenol crystal material is obtained.

[0068] The difference between the present comparative example and example 1 is that no directional crystal growth is performed, and direct cooling solidification is performed.

[0069] The preparation method of one kind of o-chlorophenol crystal material in the present comparative example comprises the following steps:

[0070] Step 1, 0.1 mol of choline chloride, 0.08 mol of tartaric acid and 0.01 mol of tris-hydroxymethyl aminomethane are placed in a vacuum drying box for drying, and then added into a flask, stirred at 60 ℃, and then kept at 55 ℃, nitrogen is introduced for 20 min, and then filtered to obtain a deep eutectic solvent (DES);

[0071] Step 2, 100 parts of o-chlorophenol and 50 parts of DES are respectively added to the upper and lower layers of an electrolytic cell to form a two-phase system, a low-voltage direct current electric field is applied at 40 ℃, after the electromigration is completed, the upper o-chlorophenol phase is taken, and then dehydrated under reduced pressure to obtain pre-purified o-chlorophenol;

[0072] Step 3, 2 mol of 2,4,6-trichloro-1,3,5-triazine, 1.6 mol of 4-aminophenol and 0.1 mol of p-diaminostilbene are cross-linked and condensed to form a porous organic polymer adsorbent (POP-OCP-1), the POP-OCP-1 particles are packed in a stainless steel column, the packing density is 0.48 g / mL, high-purity nitrogen is blown for 1 h, and the column is activated at 100 ℃ for 4 h to obtain a porous organic polymer adsorption column;

[0073] Step 4, the pre-purified o-chlorophenol is continuously flowed through the fixed bed at a flow rate of 0.5 BV / h at 30 ℃, and the outlet impurities are monitored and controlled by using a combination of color, fluorescence and GC-MS to obtain refined o-chlorophenol intermediate product;

[0074] Step 5, the refined o-chlorophenol is heated and melted under nitrogen protection, then placed in a zone melting furnace, a temperature gradient of 10 K / cm is established along the direction of the boat body, the solid-liquid interface is moved forward by moving the heating zone at a moving speed of 0.2 mm / min, and the residual trace impurities are pushed to the end along the melt direction, and the zone melting is repeated and the impurity enrichment section of 5% at the end is cut off to obtain high-purity o-chlorophenol solid;

[0075] Step 6, the high-purity o-chlorophenol melt after zone melting is subjected to directional crystal growth under the guidance of seeding at a cooling rate of 0.1 ℃ / h, the obtained crystal is subjected to annealing treatment for 12 h, and then purity detection and crystal type screening are performed, and finally o-chlorophenol crystal material is obtained.

[0076] Performance test

[0077] 1 Purity analysis

[0078] (1) Metal impurity content test: 0.1 g of crystal material was weighed into a polytetrafluoroethylene digestion tank, 5 mL of high-purity nitric acid was added, and it was sealed and digested at 120°C for 2 h. After cooling, it was diluted to 50 mL in a volumetric flask, and inductively coupled plasma mass spectrometry (ICP-MS) was used for determination. Helium collision mode was used to eliminate polyatomic ion interference, and external standard method was used for quantitative analysis. Iron, sodium, potassium, copper, zinc, magnesium, calcium and other key metal impurities were detected in turn, and the final ppb level metal content was calculated.

[0079] (2) Organic impurity content test: 10 mg of crystal was weighed into a 2 mL chromatographic sample bottle, 1 mL of chromatographically pure anhydrous ethanol was added, and vortexed until completely dissolved. A gas chromatograph-mass spectrometer (GC-MS) with an HP-5MS quartz capillary column (30 mm x 0.25 mm, 0.25 μm) was used. Gas chromatography conditions: injection port temperature 250°C; carrier gas high-purity helium, constant flow rate 1.0 mL / min; injection volume 1 μL, split ratio 10:1; programmed temperature: initial temperature 60°C, hold for 2 min, increase to 280°C at a rate of 10°C / min, hold for 5 min. Mass spectrometry conditions: electron impact ion source (EI), ion source temperature 230°C; electron energy 70 eV; quadrupole rod temperature 150°C; scan mode full scan (Scan), mass scan range m / z 35-350. The retention time and mass spectrum fragment information of each chromatographic peak in the total ion chromatogram of the sample were compared with the NIST standard mass spectrum library for preliminary qualitative analysis. The area normalization method was used to calculate the percentage of the total area of known and unknown impurity peaks (main peak + all impurity peaks) to the total peak area as the evaluation index of total organic impurity content (ppm).

[0080] Table 1 Purity analysis test data table

[0081] Sample Total metal content (ppb) Total organic impurities (ppm) Example 1 10.0 0.85 Example 2 8.8 0.73 Example 3 9.3 0.79 Comparative Example 1 112.9 12.5 Comparative Example 2 37.1 5.7 Comparative Example 3 47.6 8.2 Comparative Example 4 26.4 3.6

[0082] From Table 1, the total metal content (less than 10 ppb) and total organic impurities (<0.85 ppm) of Examples 1-3 are far superior to the comparative examples, and reach the invention target (<10 ppb, <1 ppm), which proves that the combination of "DES electro-migration-POP adsorption-zone melting" has a super strong deep removal ability for ionic and organic impurities. The DES electro-migration effectively removes metal ions and polar impurities, the POP-OCP-1 adsorbent precisely adsorbs colored bodies and fluorescent molecules, and the zone melting further eliminates trace impurities that cannot be completely removed by the previous two steps. In contrast, Comparative Example 1 lacks the steps of deep metal and polar impurity removal, and the subsequent POP adsorption and zone melting are difficult to handle high initial impurity concentration, resulting in the highest total metal (112.9 ppb) and total organic impurities (12.5 ppm) of the crystal material. Comparative Example 2 uses ordinary activated carbon instead of POP-OCP-1, which has lower adsorption capacity than the latter, and poor selective adsorption of specific colored and fluorescent impurities in the o-chlorophenol system, resulting in higher total organic impurity content than Example 1. Comparative Example 3 lacks the process of directional elimination and enrichment of impurities, and the separation efficiency of the crystal from trace impurities is limited, and the impurities will mix into the main crystal, resulting in higher total metal (47.6 ppb) and total organic impurity content (8.2 ppm).

[0083] 2Physical and chemical properties

[0084] (1) Colorimetric test: melt the sample and inject it into a Spectrosil quartz cuvette with an optical path of 10 mm, immediately seal it to prevent moisture absorption and oxidation, maintain a constant temperature of 30°C for testing, use a HunterLab UltraScanVIS colorimeter, use D65 standard light source and 10° observer conditions, measure and record the APHA (platinum-cobalt) colorimetric value of the sample, each sample is measured in triplicate, and the average value is taken.

[0085] (2) Melting point and melting point range test (DSC): weigh 3-5 mg of sample in an aluminum crucible and seal it, use a TA TAInstruments Q2000 differential scanning calorimeter, under the protection of a 50 mL / min high-purity nitrogen stream, with a temperature rise rate of 10°C / min, scan from -10°C to 50°C, analyze the DSC curve by the instrument software, read the starting temperature of the melting peak as the melting point, and calculate the temperature difference between the peak top and the peak tail as the melting range.

[0086] Table 2 Physical and chemical test data

[0087] Sample Colour (APHP) Melting point (°C) Melting range (°C) Example 1 5 31.0 0.4 Example 2 3 31.7 0.2 Example 3 4 31.6 0.3 Comparative Example 1 52 29.8 2.5 Comparative Example 2 20 30.5 1.6 Comparative Example 3 33 30.3 1.8 Comparative Example 4 12 30.9 1.1

[0088] From Table 2, it can be seen that all examples have very low color values (3-5), the surface product is clear and transparent, and the color impurities are effectively removed, and the melting range of the examples is very narrow (0.2-0.4 °C), indicating that the crystal composition is highly uniform, which is due to the directional exclusion of impurities and the perfect lattice formed by directional growth in the zone melting process. In contrast, Comparative Example 1 has the highest color value and the widest melting range, indicating that the product is dark in color and poor in purity. Comparative Example 3, which is simply recrystallized, cannot effectively enrich and cut off impurities at the end as zone melting does, resulting in a wider melting range and non-uniform product purity. The melting range of Comparative Example 4 (1.1 °C) is wider than that of Example 1, because fast and disordered crystallization easily wraps impurities, resulting in uneven purity distribution.

[0089] 3 Crystal Quality and Functional Testing

[0090] (1) Crystal Defect Density: A thin slice with a thickness of about 1 mm was cut from the middle of the crystal ingot using a precision cutting machine, and was coarsely and finely ground using 1200# and 2000# metallographic sandpaper, respectively. Then mechanical polishing was performed on a cloth coated with diamond suspension (particle size 1 μm) until the surface was mirror-like and no visible scratches were present. The prepared sample was ultrasonically cleaned with absolute ethanol and acetone for 5 minutes, and was dried with nitrogen. The sample was placed on the stage of an Olympus BX53M polarizing microscope, and the internal structure of the crystal was observed under orthogonal polarized light using a 100x objective system. At least 10 non-overlapping fields of view (each with an area of about 0.5 mm²) were randomly selected, and the macroscopic defects such as dislocation etch pits, cracks, and inclusions in each field of view were counted, and the average number of defects per unit area, i.e. the defect density (pieces / mm²), was calculated.

[0091] (2) Fluorescence Background Intensity: The crystal sample was ground into fine powder with uniform particle size under clean conditions. 100.0 mg of the powder sample was accurately weighed and uniformly filled into the grooves of a standard solid sample holder, and a glass slide was used to flatten the surface to form a smooth surface. A Horiba Fluorolog-3 fluorescence spectrometer equipped with a 150 W xenon lamp light source and a PMT detector was used. The excitation wavelength was set to 280 nm, the excitation and emission slit widths were both set to 2.0 nm, the emission spectrum range was scanned from 300-550 nm at a scan speed of 200 nm / min. Under the same conditions, a standard quinine sulfate reference (1 ppm, in 0.05 M H2SO4, the fluorescence intensity at 450 nm is a constant value) was simultaneously measured to verify the instrument state. The fluorescence emission intensity value of the sample at 350 nm was recorded as the characterization of the fluorescence background intensity (a.u.).

[0092] Table 3 Crystal Quality and Functional Testing Data Table

[0093] Sample Defect density (mm-2 2 ) Fluorescence background intensity (a.u.) Example 1 3 11 Example 2 2 9 Example 3 2 10 Comparative Example 1 24 95 Comparative Example 2 11 36 Comparative Example 3 15 63 Comparative Example 4 8 27

[0094] As shown in Table 3, the defect densities of Examples 1-3 are extremely low (2-3 defects / mm 2 ), demonstrating that the oriented crystal growth technique can form high quality crystals with complete structure, low internal stress, and few defects under the guidance of seed crystals and slow cooling. The fluorescence background intensity of the Examples is the lowest (9-11 a.u.), which is directly related to the low organic impurity content and low defect density, and is crucial for applications such as photoresists. In contrast, the high impurity content of Comparative Example 1 severely destroys the integrity of the crystal material and introduces fluorescent groups, resulting in a high defect density (24 defects / mm 2 ) and fluorescence background (94 a.u.). The defect density and fluorescence background of Comparative Example 3 are relatively high because impurities entering the crystal lattice result in more crystal defects. Comparative Example 4 does not undergo oriented crystal growth and is directly cooled and solidified, forming a polycrystal, generating grain boundaries, dislocations, and stress, resulting in a significantly higher defect density (8 defects / mm 2 ) and fluorescence background (27 a.u.) than Example 1, and the quality of the crystal decreases.

[0095] The above description is merely preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art, according to the technical range disclosed by the present application and the inventive concept of the present application, can make equivalent replacements or changes, which should be covered within the protection scope of the present application.

Claims

1. A method for preparing electronic grade high purity o-chlorophenol crystal material, characterized in that, The method comprises the following steps: Step 1, adding o-chlorophenol and deep eutectic solvent (DES) into the upper and lower layers of an electrolytic cell respectively to form a two-phase system, applying a low-voltage direct current electric field at 40-50 DEG C, taking the upper o-chlorophenol phase after electromigration, and removing water under reduced pressure to obtain pre-purified o-chlorophenol; Step 2, passing the pre-purified o-chlorophenol through a porous organic polymer adsorption column under the condition of 30-40 DEG C to obtain refined o-chlorophenol intermediate product; Step 3, placing the refined o-chlorophenol into a zone melting furnace after being heated and melted under nitrogen protection, establishing a temperature gradient along the direction of the boat body, moving the heating zone to make the solid-liquid interface advance, and pushing the residual trace impurities to the end along the melt direction, repeating the zone melting and cutting off the impurity enrichment section at the end of 5-10%, and obtaining high-purity o-chlorophenol solid; Step 4, performing directional crystal growth of the high-purity o-chlorophenol melt after zone melting under the guidance of seeding, performing purity detection and crystal type screening on the obtained crystal after annealing treatment, packaging the product meeting the electronic grade standard in a nitrogen atmosphere, and finally obtaining electronic grade high-purity o-chlorophenol crystal material.

2. The method of producing electronic grade high purity o-chlorophenol crystal material according to claim 1, characterized by, The weight parts of o-chlorophenol and deep eutectic solvent (DES) in step 1 are 100 parts and (50-80) parts respectively.

3. The method of producing electronic grade high purity o-chlorophenol crystal material according to claim 2, characterized by, The preparation method of the deep eutectic solvent (DES) is as follows: choline chloride, tartaric acid and tris(hydroxymethyl)aminomethane are placed in a vacuum drying box according to a molar ratio of 1:(0.8-1.2):(0.1-0.3), then added into a flask, stirred at 60-70 DEG C, then kept at 55-60 DEG C, and nitrogen is introduced for 20-30 min, and then filtered to obtain the deep eutectic solvent (DES).

4. The method of producing electronic grade high purity o-chlorophenol crystal material according to claim 1, characterized in that, The construction method of the porous organic polymer adsorption column in step 2 is as follows: 2,4,6-trichloro-1,3,5-triazine, 4-aminophenol and p-diaminostilbene are cross-linked and condensed to form a porous organic polymer adsorbent (POP-OCP-1) according to a molar ratio of 1:(0.8-1.5):(0.05-0.25), the POP-OCP-1 particles are packed in a stainless steel column, the packing density is 0.48-0.52 g / mL, high-purity nitrogen is blown for 1-1.5 h, and the column is activated at 100-120 DEG C for 4-5 h.

5. The method of producing electronic grade high purity o-chlorophenol crystal material according to claim 1, characterized in that, The flow rate of o-chlorophenol in step 2 is 0.5-1.0 BV / h, and the outlet impurity monitoring uses a combination of color, fluorescence and GC-MS monitoring control.

6. The method of producing electronic grade high purity o-chlorophenol crystal material according to claim 1, wherein The temperature gradient in step 3 is 10-20 K / cm, and the moving speed of the heating zone is 0.2-0.5 mm / min.

7. The method of producing electronic grade high purity o-chlorophenol crystal material according to claim 1, wherein The directional crystal growth in step 4 adopts a cooling rate of 0.1-0.2 DEG C / h, and the annealing time is 12-24 h.

8. The method of producing electronic grade high purity o-chlorophenol crystal material according to claim 1, wherein The metal impurity content in the o-chlorophenol crystal material finally obtained in step 4 is less than 10 ppb, and the total content of organic impurities is less than 1 ppm.

Images