A non-silicon non-ether defoamer and preparation method thereof

Abstract

The invention discloses a non-silicon non-ether type defoamer and a preparation method thereof, wherein a nitrogen-containing heterocyclic compound and a long-chain isocyanate are subjected to a branching reaction under the action of a catalyst to obtain the defoamer; the nitrogen-containing heterocyclic compound structural formula contains 2 to 3 groups, so as to react with the long-chain isocyanate to form a highly branched structure; the long-chain isocyanate structural formula is R-N=C=O, wherein R is a C10-C18 long-chain alkyl, and a relatively long hydrophobic long-chain alkyl can well cope with the foam system for defoaming. The present invention can form a highly branched molecular structure by mixing a nitrogen heterocyclic compound and a long-chain isocyanate, and the defoamer can be defoamed without adding an emulsifier for complex emulsification, and has good temperature resistance, so that the defoamer can be applied to the defoaming and defoaming of a foam system at a higher temperature.

Description

Technical Field

[0001] The invention belongs to the field of industrial defoaming additives, and particularly relates to a non-silicon and non-ether defoaming agent and a preparation method thereof. Background Art

[0002] With the rapid development of the national economy, higher requirements have been put forward for the industrial production capacity of all walks of life in my country. Foam in industrial production is a major problem that cannot be ignored and will bring great harm to industrial production. For example, in the production of beer, alcohol manufacturing, and major antibiotics in medicine, various fermentation tanks, reactors, and cooking tanks in production, in order to prevent the appearance of foam and cause overflow losses, the feed coefficient must be controlled, which greatly limits the production capacity; for example, the filling process of paper mills, sugar factories, and the oiling process of the weaving process of textile mills often cause the overflow of precious raw materials due to foam overflow, causing unnecessary losses; there are also some specific industrial chemical reaction products. The presence of foam will cause gas retention, prolong the reaction cycle, and cause unnecessary power consumption increase; what's more, foam will pollute the environment and cause accidents. For example, an oil refinery in a city on the southeast coast did not use defoaming agents in time due to the overflow of residual oil foam, causing a major fire and heavy losses. Industrial foam not only causes waste of raw materials, but also poses a great threat to human life and property.

[0003] Therefore, in order to avoid the harm caused by foam and improve production efficiency in industrial production, defoaming agents are usually added to reduce the impact of foam. At present, there are many types of defoamers suitable for industrial production with different performances. They can be mainly divided into silicone type, polyether type and grease type. As the first generation of defoamers, grease type defoamers have limited use scope, low removal rate for dense foam, and easy to affect the foaming system, so their development is restricted. Polyether defoamers have low foam breaking rate. If foam is suddenly generated in the foaming system, it cannot quickly and effectively eliminate the foam. Only by adding an appropriate amount of defoamer can the defoaming effect be achieved, and the cost of use is high. Compared with its excellent defoaming performance, the foam suppression of silicone defoamers is slightly insufficient, and silicone is more difficult to emulsify than other oils. The emulsification step is the key and difficulty in the compounding process. Once the emulsification is incomplete and incomplete, serious demulsification and stratification will occur, which will affect the defoaming and defoaming performance of the defoamer. Summary of the invention

[0004] Purpose of the invention: The technical problem to be solved by the present invention is to provide a multifunctional molecular defoamer to replace the traditional defoamer in view of the shortcomings of the prior art, which is suitable for various industrial productions and can achieve defoaming of different foam systems.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing a non-silicon and non-ether defoamer, comprising subjecting a nitrogen-containing heterocyclic compound and a long-chain isocyanate to a branching reaction under the action of a catalyst to obtain the defoamer;

[0007] The nitrogen-containing heterocyclic compound structural formula contains 2 to 3 Groups to facilitate reaction with long-chain isocyanates to form highly branched structures;

[0008] The long-chain isocyanate has a structural formula of RN=C=O, wherein R is a C10-C18 long-chain alkyl group, and the relatively long hydrophobic long-chain alkyl group can effectively defoam the foam system.

[0009] Furthermore, the nitrogen-containing heterocyclic compound is selected from any one of melamine and 2,4,6-triaminopyrimidine or a combination of two thereof.

[0010] Furthermore, the long-chain isocyanate is selected from any one of dodecaned isocyanate, hexadecyl isocyanate, and octadecyl isocyanate, or a combination of two or more thereof.

[0011] Furthermore, the catalyst is dibutyltin dilaurate.

[0012] Furthermore, the preparation method of the non-silicon non-ether defoamer of the present invention specifically comprises the following steps:

[0013] (1) dispersing the nitrogen-containing heterocyclic compound in an organic dispersant to obtain a dispersed solution of the nitrogen-containing heterocyclic compound;

[0014] (2) adding a long-chain isocyanate and a catalyst to the dispersed solution of the nitrogen-containing heterocyclic compound in step (1), and stirring the mixture sufficiently at room temperature for reaction;

[0015] (3) After the reaction is completed, the precipitate is separated and obtained.

[0016] Preferably, in step (1), the organic dispersant is selected from any one of dioxane and dimethyl sulfoxide or a combination of both.

[0017] Preferably, the reaction molar ratio of the nitrogen-containing heterocyclic compound to the long-chain isocyanate is 1:3-6; the molar ratio of the catalyst not participating in the reaction to the nitrogen-containing heterocyclic compound is 0.02-0.06:1, and the mass ratio of the organic dispersant not participating in the reaction to the nitrogen-containing heterocyclic compound is 5-10:1.

[0018] Furthermore, the method further comprises dehydrating the reactants and the container before the reaction synthesis, and heating the nitrogen-containing heterocyclic compound, the long-chain isocyanate and the catalyst at 110-120° C. for 0.5-1 h to fully dehydrate them.

[0019] Preferably, in step (2), the reaction is carried out in a three-necked flask and refluxed using a condenser; a drying tube is used at the upper end of the condenser to prevent moisture in the air from entering, the reaction temperature is room temperature 10 to 30°C, the reaction time is 30 to 50 minutes, and the stirring speed is 300 to 360 r / min.

[0020] Preferably, in step (3), the precipitate is separated by centrifugation at a speed of 10,000 r / min for 5 to 10 min. The upper organic clear liquid after centrifugation is recovered as a dispersant for the next reaction, and the solid defoaming agent is dried at 60 to 80°C.

[0021] Furthermore, the non-silicon and non-ether defoaming agent prepared by the above preparation method is also within the protection scope of the present invention.

[0022] The non-silicon and non-ether defoaming agent prepared by the invention can be used in foam systems generated by various foaming agents or complex foam systems caused in industrial production processes.

[0023] Beneficial effects:

[0024] (1) The present invention forms a highly branched molecular structure by mixing nitrogen heterocyclic compounds and long-chain isocyanates. This defoamer can defoam without adding an emulsifier for complex emulsification and has good temperature resistance, so that the defoamer can be used for defoaming and suppressing foam in foam systems at higher temperatures.

[0025] (2) The method provided by the present invention has the advantages of cost saving, energy saving and environmental protection, short reaction time, mild reaction conditions, and is suitable for large-scale industrial production.

[0026] (3) The molecular defoamer prepared by the method of the present invention can achieve defoaming of different foam systems by adjusting its own branching degree and hydrophilicity and hydrophobicity, and has great flexibility. It is expected to replace traditional defoamers and can be applied to various industrial productions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0028] Figure 1 It is the synthetic route map of hyperbranched melamine molecular defoamer.

[0029] Figure 2 This is the infrared spectrum of the hyperbranched melamine molecular defoamer, where M is melamine and Cl is octadecyl isocyanate. Different branching degrees are formed by reacting in different proportions.

[0030] Figure 3It is the performance of hyperbranched melamine molecular defoamer compared with commercially available defoamers. DETAILED DESCRIPTION

[0031] The present invention can be better understood with reference to the following examples.

[0032] Example 1

[0033] This embodiment provides a defoamer material prepared based on melamine and long-chain isocyanate, and the preparation method thereof is as follows:

[0034] The entire reaction is carried out at room temperature and pressure, and a drying device is placed on the double-necked round-bottom flask to prevent trace moisture in the air from entering the reaction system.

[0035] (1) Before the experiment, 1.26 g of melamine powder was accurately weighed and placed in a vacuum drying oven at 110 °C for 0.5 h to eliminate the interference of trace water on the experiment.

[0036] (2) Add the dried melamine to 10 g of 1,4-dioxane at room temperature and start stirring. After the melamine is completely dispersed in the 1,4-dioxane, add 10.5 g of octadecyl isocyanate dropwise to the reaction system.

[0037] (3) Stir and add 0.001 g of the catalyst dibutyltin dilaurate. Under the action of the catalyst, the reaction process continues for 30 minutes and then stops. The synthetic route is as follows: Figure 1 shown.

[0038] (4) collecting the defoamer generated by the reaction at the bottom by centrifugation and drying it at 60° C. for 6 h to obtain a melamine-octadecyl isocyanate (1-3 type) hyperbranched defoamer.

[0039] Example 2

[0040] This embodiment provides a defoamer material prepared based on melamine and long-chain isocyanate, and the preparation method thereof is as follows:

[0041] The entire reaction is carried out at room temperature and pressure, and a drying device is placed on the double-necked round-bottom flask to prevent trace moisture in the air from entering the reaction system.

[0042] (1) Before the experiment, 1.26 g of melamine powder was accurately weighed and placed in a vacuum drying oven at 110 °C for 0.5 h to eliminate the interference of trace water on the experiment.

[0043] (2) Add the dried melamine to 10 g of 1,4-dioxane at room temperature and start stirring. After the melamine is completely dispersed in the 1,4-dioxane, add 20.1 g of octadecyl isocyanate dropwise to the reaction system.

[0044] (3) Stir and add 0.001 g of the catalyst dibutyltin dilaurate. Under the action of the catalyst, the reaction process continues for 30 minutes and then stops. The synthetic route is as follows: Figure 1 shown.

[0045] (4) collecting the defoamer generated by the reaction at the bottom by centrifugation and drying it at 60° C. for 6 h to obtain a melamine-octadecyl isocyanate (1-6 type) hyperbranched defoamer.

[0046] Example 3

[0047] This embodiment provides a defoamer material prepared based on melamine and long-chain isocyanate, and the preparation method thereof is as follows:

[0048] The entire reaction is carried out at room temperature and pressure, and a drying device is placed on the double-necked round-bottom flask to prevent trace moisture in the air from entering the reaction system.

[0049] (1) Before the experiment, 1.26 g of melamine powder was accurately weighed and placed in a vacuum drying oven at 110 °C for 0.5 h to eliminate the interference of trace water on the experiment.

[0050] (2) Add the dried melamine to 10 g of 1,4-dioxane at room temperature and start stirring. After the melamine is completely dispersed in the 1,4-dioxane, add 11.4 g of dodecyl isocyanate dropwise to the reaction system.

[0051] (3) Stir and add 0.001 g of the catalyst dibutyltin dilaurate. Under the action of the catalyst, the reaction process continues for 30 minutes and then stops. The synthetic route is as follows: Figure 1 shown.

[0052] (4) The defoamer generated by the reaction at the bottom is collected by centrifugation and dried at 60°C for 6 hours to obtain a melamine-dodecyl isocyanate (1-6 type) hyperbranched defoamer. This example is intended to illustrate that the length of the branching can be controlled when synthesizing the defoamer, and different effects can be achieved according to the length.

[0053] Isocyanate compounds contain isocyanate groups (-NCO) with highly unsaturated bonds, so their chemical properties are very active. Since the electron cloud density on oxygen and nitrogen atoms is large, their electronegativity is large. The oxygen atom of the -NCO group has the largest electronegativity and is a nucleophilic center. It can attract hydrogen atoms on active hydrogen compound molecules to generate hydroxyl groups, but the hydroxyl groups on unsaturated carbon atoms are unstable and will eventually rearrange to urea. Carbon atoms have the lowest electron cloud density and are highly positively charged. They are electrophilic centers and are easily attacked by nucleophilic reagents. Therefore, the reaction mechanism of the present invention is as follows:

[0054]

[0055] By controlling the proportion of added isocyanate, partial or complete substitution of hydrogen on the nitrogen-containing heterocyclic compound can be achieved, and finally defoamers with different hyperbranching degrees can be tested. Figure 1 Shown is the synthetic route of the melamine hyperbranched defoamer of this example.

[0056] The formation and chemical structure of the hyperbranched melamine molecular defoamer prepared in Examples 1 to 3 were analyzed by Fourier infrared spectroscopy ( Figure 2 ). The raw material melamine is 3500-3400cm -1 There are sharp double peaks near the NH2 group, which corresponds to the characteristic peak of the bending vibration of NH in the primary amino (-NH2) group in its structure ( Figure 2 Middle M line). Infrared spectrum of raw material octadecyl isocyanate ( Figure 2 Cl line) at 3000-2800cm -1 and 1470cm -1 Sharp double peaks and single peaks appear near the structure, corresponding to the stretching vibration peaks and bending vibration peaks of CH of -CH3 and / or -CH2 with highly symmetrical R groups in the structure. In the isocyanate (-N=C=O) structure, the C=O and C=N double bonds share a C atom, resulting in strong coupling, which leads to the splitting of the spectrum into two bands, corresponding to 2265cm in the spectrum. -1 and 1355cm -1 There are two stretching vibration peaks nearby. Figure 2 The three lines M-Cl in the figure are three melamine molecular defoamers with different hyperbranching degrees prepared under different molar ratios. The three melamine defoamers prepared at a molar ratio of 1:6 have a wavelength of 3500-3400 cm -1 Nearby and 1355cm -1 There are no corresponding characteristic peaks nearby. 3500-3400cm -1 The disappearance of the vibration peak near 1355cm -1The disappearance of the nearby vibration peaks should be due to the opening of the C=N double bond in the isocyanate. This example shows that the reaction can proceed in different proportions and the target product can be synthesized under the action of a catalyst.

[0057] Example 4

[0058] This embodiment provides a defoamer material prepared based on 2,4,6-triaminopyrimidine and long-chain isocyanate, and the preparation method thereof is as follows:

[0059] The entire reaction is carried out at room temperature and pressure, and a drying device is placed on the double-necked round-bottom flask to prevent trace moisture in the air from entering the reaction system.

[0060] (1) Before the experiment, 1.253 g of 2,4,6-triaminopyrimidine powder was accurately weighed and placed in a vacuum drying oven at 110 °C for 0.5 h to eliminate the interference of trace water on the experiment.

[0061] (2) Add dried 2,4,6-triaminopyrimidine to 10 g of 1,4-dioxane at room temperature and start stirring. After melamine is completely dispersed in 1,4-dioxane, add 10.5 g of octadecyl isocyanate dropwise to the reaction system.

[0062] (3) Stir and add 0.001 g of the catalyst dibutyltin dilaurate. Under the action of the catalyst, the reaction process continues for 30 minutes and then stops. The synthetic route is as follows: Figure 1 shown.

[0063] (4) The defoamer generated by the reaction at the bottom is collected by centrifugation and dried at 60°C for 6 hours to obtain a hyperbranched defoamer of 2,4,6-triaminopyrimidine-octadecyl isocyanate (type 1-3). This example is intended to illustrate that when synthesizing a defoamer, the nitrogen-containing heterocyclic compound is not limited to melamine, and any nitrogen-containing heterocyclic compound with two or more amino groups can be used.

[0064] Example 5

[0065] This embodiment provides a defoamer material prepared based on melamine and long-chain isocyanate, and the preparation method thereof is as follows:

[0066] The entire reaction is carried out at room temperature and pressure, and a drying device is placed on the double-necked round-bottom flask to prevent trace moisture in the air from entering the reaction system.

[0067] (1) Before the experiment, 1.26 g of melamine powder was accurately weighed and placed in a vacuum drying oven at 110 °C for 0.5 h to eliminate the interference of trace water on the experiment.

[0068] (2) Add the dried melamine to 8.8 g of dimethyl sulfoxide at room temperature and start stirring. After the melamine is completely dispersed in the dimethyl sulfoxide, add 10.5 g of octadecyl isocyanate dropwise to the reaction system.

[0069] (3) Stir and add 0.001 g of the catalyst dibutyltin dilaurate. Under the action of the catalyst, the reaction process continues for 30 minutes and then stops. The synthetic route is as follows: Figure 1 shown.

[0070] (4) The defoamer generated by the reaction at the bottom is collected by centrifugation and dried at 60°C for 6 hours to obtain a melamine-octadecyl isocyanate (1-3 type) hyperbranched defoamer. This example is intended to illustrate that during the reaction, the added dispersant is not limited to 1,4-dioxane, and any solvent without active hydrogen can be used, and the dispersant does not participate in the reaction and can be recycled repeatedly.

[0071] Example 6

[0072] Taking the commercially available polyether stearate defoamer (XS-02 type) as a comparative example, the defoamer prepared in Example 2 of the present invention and the same foaming system were subjected to defoaming and foam suppression performance experiments. The test method was referenced and improved on the national defoamer test performance standard GB / T 26527-2011. First, a 0.5% concentration of foaming liquid was prepared, and four different types of foaming liquids (anionic, cationic, nonionic, and commercial mixed compound) were selected to simulate the foam system generated by various simulated industrial foaming liquids; the rapid shaking bottle method was used for testing, 30mL of foaming liquids of different systems were added to a stoppered measuring cylinder, the stoppered measuring cylinder cover was covered and shaken vigorously for 30 times, and the measuring cylinder was left to stand and wait for the foam column to stabilize. A certain amount of defoamer was added, and the defoaming performance was evaluated by comparing the volume of the foam column destroyed by the defoaming liquid within 200s; the foam suppression performance was evaluated by the volume of the foam column generated again after shaking again for 200s, and finally the defoaming efficiency and foam suppression efficiency were calculated.

[0073] The defoaming efficiency of the defoamer is η D :

[0074]

[0075] Where η D is the defoaming efficiency, V max is the maximum foam height of the foaming liquid, V f It is the remaining height of the foam column after defoaming for 200s.

[0076] Definition of antifoam efficiency η A :

[0077]

[0078] Where η A is the foam suppression efficiency, V max is the maximum foam height of the foaming liquid, V a It is the height of the foam column generated again 200s after re-shaking.

[0079] The results are as follows Figure 3 It can be seen that the defoaming agent of the present invention has rapid defoaming performance, good defoaming performance and long-lasting foam suppression for different systems, and has strong applicability in industrial defoaming.

[0080] The present invention provides a non-silicon non-ether type defoamer and a method for preparing the same. There are many methods and approaches to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A method for preparing a non-silicon non-ether defoamer, characterized in that: The nitrogen-containing heterocyclic compound and the long-chain isocyanate are subjected to a branching reaction under the action of a catalyst to obtain: ; Wherein, R is selected from a long-chain alkyl group of C12, C16, or C18; The nitrogen-containing heterocyclic compound is selected from melamine; The long-chain isocyanate is selected from any one of dodecaned isocyanate, hexadecyl isocyanate and octadecyl isocyanate; The catalyst is dibutyltin dilaurate; The non-silicon non-ether defoamer is prepared by the following steps: (1) dispersing the nitrogen-containing heterocyclic compound in an organic dispersant to obtain a dispersed solution of the nitrogen-containing heterocyclic compound; (2) adding a long-chain isocyanate and a catalyst to the dispersed solution of the nitrogen-containing heterocyclic compound in step (1), and stirring the mixture sufficiently at room temperature to react; (3) After the reaction is completed, the precipitate is separated and obtained; In step (2), the reaction temperature is 10-30°C and the reaction time is 30-50 min.

2. The method for preparing the non-silicon non-ether defoamer according to claim 1, characterized in that: In step (1), the organic dispersant is selected from any one of dioxane and dimethyl sulfoxide or a combination of the two.

3. The method for preparing the non-silicon non-ether defoamer according to claim 1, characterized in that: The reaction molar ratio of the nitrogen-containing heterocyclic compound to the long-chain isocyanate is 1:3-6; the molar ratio of the catalyst to the nitrogen-containing heterocyclic compound is 0.02-0.06:1; and the mass ratio of the organic dispersant to the nitrogen-containing heterocyclic compound is 5-10:

1.

4. The method for preparing the non-silicon non-ether defoamer according to claim 1, characterized in that: The method also includes dehydrating the reactants and the container before the reaction synthesis, and heating the nitrogen-containing heterocyclic compound, the long-chain isocyanate and the catalyst at 110-120° C. for 0.5-1 hour for dehydration.

5. The method for preparing the non-silicon non-ether defoamer according to claim 1, characterized in that: In step (2), the reaction is carried out in a three-necked flask and refluxed using a condenser; a drying tube is used at the upper end of the condenser to prevent moisture in the air from entering, and the stirring speed is 300-360 r / min.

6. The non-silicon and non-ether defoaming agent prepared by any one of the preparation methods of claims 1 to 5.

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