Disclosure of Invention
The invention aims to provide a modified composite molecular sieve and preparation and application thereof, and the prepared composite molecular sieve has the characteristics of high oil phase dispersibility, long service life, low application system viscosity and the like.
The purpose of the invention can be realized by the following technical scheme:
one of the technical schemes of the invention provides a preparation method of a modified composite molecular sieve, which comprises the following steps:
(1) mixing a 4A type molecular sieve, a NaY type molecular sieve and a mordenite type molecular sieve, treating by using a calcium chloride solution, and washing to obtain a molecular sieve mixture;
(2) mixing the low-carbon organic acid with the molecular sieve mixture, and performing primary modification treatment;
(3) and separating the product after the primary modification, mixing the product with the long carbon chain modifier, and carrying out heat treatment to obtain the target product.
In the invention, the composite molecular sieve is used as a molecular sieve raw material, and the micro-moisture is removed by utilizing the structural difference and the polarity difference of the pore passages of the molecular sieve. The composite molecular sieve has high acid resistance, is resistant to the treatment of low-carbon chain organic acid, and can improve the acid resistance of the polyurethane adhesive when being applied to a polyurethane system. Further, the weight ratio of the 4A type molecular sieve, the NaY type molecular sieve and the mordenite molecular sieve is (50-70): (20-30): (10-20).
Further, the silicon-aluminum ratio in the mordenite molecular sieve is 10-15.
According to the invention, the internal structure of the molecular sieve is stabilized through calcium ion treatment, the molecular sieve structure is prevented from being damaged through modification and other treatments, and the influence of the molecular sieve on the water absorption performance is reduced. Further, the mass concentration of the calcium chloride solution is 2-5%, and when the calcium chloride solution is treated, the ratio of the total amount of the three molecular sieves to the mass of the calcium chloride solution is 1: (3-8).
Further, the temperature of the calcium chloride solution is 25-50 ℃ and the time is 1-3 h.
In the invention, the low-carbon organic acid is used for primary modification, so that the pore channel distribution of the molecular sieve is improved, amorphous substances in the pore channel are reduced, and the heat of adsorption is reduced. And meanwhile, water and organic acid are used for filling the molecular sieve pore channel, so that the long carbon chain modifier is prevented from entering the molecular sieve pore channel. Further, in the step (2), the low-carbon organic acid is at least one of oxalic acid, acetic acid or citric acid, and the mass ratio of the low-carbon organic acid to the molecular sieve mixture is (1-5): 100.
Preferably, the preliminarily modified product is subjected to suction filtration to obtain a filter cake, and then is mixed with the long carbon chain modifier in a mechanical grinding mode, wherein the grinding time is preferably 5-20 min.
In the invention, the long carbon chain modifier is used for only organically modifying the surface of the molecular sieve, so that the obtained molecular sieve particles can be uniformly distributed in a polyol system. Further, in the step (3), the long carbon chain modifier is at least one of pentadecanoic acid, hexadecanoic acid, heptadecanoic acid or octadecanoic acid, and the mass ratio of the long carbon chain modifier to the molecular sieve mixture is (0.5-3): 100.
in the invention, the modification of long carbon chain is combined with the activation of molecular sieve by vacuum heat treatment, and further, in the step (3), the heat treatment specifically comprises the following steps: under vacuum, firstly heating to 120-150 ℃, treating for 2-5 h, and continuously heating to 250-300 ℃ for treating for 2-5 h.
The second technical scheme of the invention provides a modified composite molecular sieve which is prepared by the preparation method.
The third technical scheme of the invention provides application of the modified composite molecular sieve, and the modified composite molecular sieve is used for removing moisture in a polyurethane binder system.
Compared with the prior art, the invention has the following advantages:
1) the modified molecular sieve is a composite of three molecular sieves with different silicon-aluminum ratios, and the micro-moisture is removed by utilizing the structural difference and the polarity difference of pore channels of the molecular sieves, so that the service life of the system is prolonged. The composite molecular sieve has high acid resistance, and can improve the acid resistance of the polyurethane adhesive when being applied to a polyurethane system.
2) The calcium ions are utilized to stabilize the composite molecular sieve pore channel structure, so that the damage to the molecular sieve structure after organic acid treatment is effectively avoided, and the water adsorption performance of the molecular sieve is stabilized.
3) The low-carbon organic acid is used for removing partial aluminum and amorphous substances in the molecular sieve, so that the pore channel distribution of the molecular sieve is improved, and the heat of adsorption is reduced. The low-carbon organic acid fills the pores of the molecular sieve, so that the long-carbon-chain organic acid is prevented from entering the inside of the pores of the molecular sieve, the low-carbon organic acid is removed in the subsequent vacuum activation process, and the water absorption performance of the molecular sieve is maintained.
4) The long carbon chain modifier is utilized to only carry out organic modification on the surface of the molecular sieve, so that the activated molecular sieve particles can be uniformly distributed in the polyol, the agglomeration is avoided, the product has the advantages of high dispersibility and low system viscosity, the initial viscosity of an application system can be reduced, and the working life is prolonged.
Detailed Description
The present invention will be described in detail with reference to specific examples. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.
In the following examples, the long carbon chain modifier of octadecanoic acid was a product of national chemical group, Inc., and the polymethylene polyphenyl isocyanate (PAPI-27) was a product of Dow chemical company. Otherwise, unless otherwise specified, all the conventional commercial raw materials or conventional processing techniques are used in the art.
Example 1
Mixing the 4A type molecular sieve, the NaY type molecular sieve and the mordenite type molecular sieve according to the proportion of 50:30:20, wherein the silicon-aluminum ratio of the mordenite type molecular sieve is about 10. Calcium chloride solution with the mass concentration of 2% is used for processing for 3h at the temperature of 25 ℃ and the solid-to-liquid ratio of 1: 8. After washing, the mixture is treated by using a low-carbon organic acid solution, wherein the mass ratio of the low-carbon organic acid (oxalic acid in the embodiment) to the molecular sieve mixed powder is 1:100, and the treatment time is 3 hours. And performing filter pressing to obtain a filter cake after treatment, adding octadecanoic acid, wherein the mass ratio of the octadecanoic acid to the molecular sieve filter cake is 0.5:100, mixing, grinding for 5min, performing vacuum heat treatment at 120 ℃, treating for 2h, heating to 250 ℃, and treating for 2h to obtain the modified composite molecular sieve.
Example 2
Mixing a 4A type molecular sieve, a NaY type molecular sieve and a mordenite type molecular sieve according to the weight ratio of 70: 20: 10, wherein the silicon-aluminum ratio of the mordenite molecular sieve is 15. Calcium chloride solution with the mass concentration of 5% is used for processing for 2h at the temperature of 25 ℃ and the solid-to-liquid ratio of 1: 3. After washing, the mixture is treated by using a low-carbon organic acid solution, wherein the mass ratio of the low-carbon organic acid (acetic acid in the embodiment) to the molecular sieve mixed powder is 5:100, and the treatment time is 3 hours. And performing filter pressing to obtain a filter cake after treatment, adding pentadecanoic acid, mixing and grinding for 10min after the pentadecanoic acid and the molecular sieve are in a ratio of 1:100, performing vacuum heat treatment at 130 ℃ for 5h, heating to 300 ℃, and performing treatment for 2h to obtain the modified composite molecular sieve.
Example 3
Mixing a 4A type molecular sieve, a NaY type molecular sieve and a mordenite type molecular sieve according to the weight ratio of 60: 20: 20, wherein the silicon-aluminum ratio of the mordenite molecular sieve is 12. Calcium chloride solution with the mass concentration of 5% is used for processing for 1h at the temperature of 50 ℃ and the solid-to-liquid ratio of 1: 8. After washing, the powder is treated by using a low-carbon organic acid solution, wherein the mass ratio of the low-carbon organic acid (citric acid in the embodiment) to the powder is 2:100, and the treatment time is 1 h. And performing filter pressing to obtain a filter cake after treatment, adding hexadecanoic acid, wherein the ratio of the hexadecanoic acid to the molecular sieve is 3:100, mixing, grinding for 20min, performing vacuum heat treatment at 150 ℃ for 3h, heating to 250 ℃ for 5h to obtain the modified composite molecular sieve.
Example 4
Mixing a 4A type molecular sieve, a NaY type molecular sieve and a mordenite type molecular sieve according to the weight ratio of 60: 30: 10, wherein the silicon-aluminum ratio of the mordenite molecular sieve is 15. Calcium chloride solution with the mass concentration of 3% is used for processing for 2h at the temperature of 30 ℃ and the solid-to-liquid ratio of 1: 5. After washing, the powder is treated by using a low-carbon organic acid solution, wherein the mass ratio of the low-carbon organic acid (acetic acid in the embodiment) to the powder is 3:100, and the treatment time is 2 hours. And performing filter pressing to obtain a filter cake after treatment, adding heptadecanoic acid, wherein the ratio of the heptadecanoic acid to the molecular sieve is 2:100, mixing, grinding for 15min, performing vacuum heat treatment at 150 ℃ for 1h, heating to 280 ℃ for 5h to obtain the modified composite molecular sieve.
Example 5
Mixing a 4A type molecular sieve, a NaY type molecular sieve and a mordenite type molecular sieve according to the weight ratio of 70: 20: 10, wherein the silicon-aluminum ratio of the mordenite molecular sieve is 10. Calcium chloride solution with the mass concentration of 5% is used for processing for 3h at the temperature of 25 ℃ and the solid-to-liquid ratio of 1: 3. After washing, the powder is treated by using a low-carbon organic acid solution, wherein the mass ratio of the low-carbon organic acid (oxalic acid in the embodiment) to the powder is 5:100, and the treatment time is 3 hours. And performing filter pressing to obtain a filter cake after treatment, adding pentadecanoic acid, mixing the pentadecanoic acid and the molecular sieve according to the ratio of 1:100, grinding for 10min, performing vacuum heat treatment at 130 ℃ for 5h, heating to 300 ℃, and treating for 2h to obtain the modified composite molecular sieve.
Comparative example 1
Compared with the example 1, the method is basically the same, except that the molecular sieve in the example is pure 4A molecular sieve with equal mass.
Comparative example 2
Compared with the example 1, the method is basically the same, except that the molecular sieve in the example is a pure NaY molecular sieve with equal mass.
Comparative example 3
Compared with the example 1, the method is basically the same, except that the molecular sieve in the example is the pure mordenite molecular sieve with equal mass.
Comparative example 4
Essentially the same as in example 1, except that the calcium chloride treatment step was eliminated in this example.
Comparative example 5
The process is essentially the same as example 1, except that the lower organic acid treatment step is eliminated.
Comparative example 6
Essentially the same as in example 1, except that the long chain modifier treatment step was eliminated.
After the obtained composite molecular sieve and castor oil are uniformly mixed according to the proportion of 1:1, a DV-2T RV type viscometer is used for testing the viscosity, the testing condition is 25 ℃, a number six rotor is used, and the rotating speed is 30 rpm. The viscosity of the resulting sample was tested.
Weighing 5g of the obtained composite molecular sieve, placing the weighed composite molecular sieve on a marble flat plate, dropwise adding refined linseed oil by using a burette, wherein the oil adding amount is not more than 10 drops each time, pressing and grinding by using a regulating knife after adding the refined linseed oil, so that oil is infiltrated into a sample to be tested, and continuously dropwise adding the refined linseed oil at the speed until the oil and the sample form a block. And (3) from the moment, adding one drop of the linseed oil, fully grinding by using a knife, recording the volume of the consumed refined linseed oil to obtain the oil absorption value of the sample by calculating when a paste with uniform consistency is formed, is not cracked and broken right and can be adhered to a flat plate as an end point.
And testing the static water adsorption performance of the obtained composite molecular sieve.
And (3) uniformly mixing 10g of molecular sieve powder with 10mL of water, and recording the temperature change in the mixing process to obtain the water adsorption temperature rise.
The composite molecular sieve and the castor oil are uniformly mixed according to the ratio of 1:1, a high-shear stirring rod is adopted for stirring for 3 minutes during mixing, about 50g of paste is prepared and stored for 12 hours at a moisture-proof constant temperature, 9.85g of PAPI27 is added into the paste, then the paste is stirred for 2 minutes at the stirring speed of 240r/min to obtain the paste to be tested, the working life of a sample is reflected by intermittently testing the viscosity change of the paste, and the time consumed when the viscosity of the paste reaches 56 Pa.s is the working life of the sample.
The results of the tests of example 1 and comparative examples 1-6 are shown in Table 1:
TABLE 1
Comparing the data in table 1, example 1 has a low application viscosity and a high pot life. Compared with the difference between single raw powder and composite powder, the single raw powder has the problems of low static water or high viscosity, high oil absorption value and the like, the product has short working life, the composite molecular sieve can avoid the problems of low static water or high viscosity and the like of the single molecular sieve, and the working life of the product is also obviously prolonged. Comparative example 4, no calcium ion pretreatment was introduced, the water adsorption of the molecular sieve was significantly reduced, which indicates that the internal structure of the molecular sieve could be stabilized by calcium ion treatment to avoid the damage of modification to the molecular sieve structure. Comparative example 5, the temperature rise of water adsorption was significantly increased without treating the sample with an organic acid, and the pot life was somewhat shortened as compared with example 1. Comparative example 6, the long-chain modifier is not used for modification, the oil absorption value and the viscosity are both obviously increased, which shows that the sample has obviously poor oleophylic property and is difficult to be uniformly dispersed in a polyol system.
Example 6
The same as in example 2, except that the calcium chloride treatment temperature was 45 ℃.
Example 7
Compared with the example 2, the calcium chloride solid-liquid ratio is basically the same, except that the calcium chloride solid-liquid ratio is 1: 8.
Example 8
Compared with the embodiment 2, the method is basically the same, except that the mass ratio of the low-carbon organic acid to the powder is 2: 100.
Example 9
Compared with the embodiment 2, the method is basically the same, except that the mass ratio of the long-chain modifier to the powder is 3: 100.
Example 10
Compared with the embodiment 2, the method is basically the same, except that the long-chain modifier is a mixed modifier of pentadecanoic acid and octadecanoic acid, and the mass ratio of the pentadecanoic acid to the octadecanoic acid is 1: 1.
Example 11
Compared with example 2, the same, except that the weight ratio of the type 4A molecular sieve, NaY molecular sieve and mordenite molecular sieve is 60: 25: 15.
example 12
Compared with example 2, the same is true, except that the mordenite molecular sieve has a silica to alumina ratio of 12.
The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.