A process for the preparation of a naphthalene sulfonate condensate

Abstract

The application discloses a preparation method of a naphthalene sulfonate condensate, which directly and effectively introduces an alkyl group on a condensation chain structure through the method of adding an alkyl aldehyde first and then adding formaldehyde, is simple to operate, does not need to prepare an alkyl naphthalene sulfonic acid separately, does not produce acid wastewater, has a simple, efficient and safe overall preparation process, and has an excellent development prospect.

Description

Technical Field

[0001] This invention belongs to the field of naphthalene sulfonate condensate surfactant technology, and specifically relates to a method for preparing naphthalene sulfonate condensates. Background Technology

[0002] Naphthalene sulfonate formaldehyde condensates are anionic surfactants with excellent emulsifying, dispersing, wetting, and penetrating properties, and are currently widely used in industries such as leather, dyes, pesticides, and concrete. In pesticide adjuvant applications, the Morwet series of wetting and dispersing agents developed by Akzo Nobel is a leading example. Specifically designed for wetting and dispersing, Morwet is highly versatile and holds a leading position in the industry. Examples include Morwet D425, whose structure consists of alkyl naphthalene sulfonate formaldehyde condensates.

[0003] Most of the naphthalene sulfonate formaldehyde condensates used in China are naphthalene sulfonate formaldehyde condensates with naphthalene or methylnaphthalene as starting materials (such as NNO or MF series dispersants). Because they have no alkyl chain or the chain length is too short, it is not possible to adjust the lipophilic-water ratio and steric hindrance as dispersants, which affects their dispersion effect in water-dispersible granules and suspensions. As a result, there are large differences in various performance indicators in the water-dispersible granules and suspensions produced.

[0004] Based on the above problems, current methods mainly involve introducing long-chain alkyl groups onto the naphthalene ring to synthesize alkyl naphthalene sulfonate formaldehyde condensates. For example, patent application CN107602421A discloses a process for preparing a formaldehyde condensate of naphthalene sulfonic acid and butyl naphthalene sulfonic acid. This process first prepares the butyl naphthalene sulfonic acid condensation monomer, using a large amount of acid (the amount of sulfuric acid is up to 10 times the amount of naphthalene). After the reaction, a large amount of waste acid needs to be removed by settling and separating. This not only increases the cost of raw materials but also generates a large amount of acidic wastewater, polluting the environment.

[0005] For example, Zhao Zhongkui et al. (Synthesis and Performance Study of Decylmethylnaphthalene Sulfonate Surfactant, Journal of Dalian University of Technology, 2008, 48(3): 318-322) used expensive long-chain bromoalkane and methylnaphthalene in cyclohexane catalyzed by anhydrous aluminum trichloride to prepare long-chain alkylnaphthalene. Not only are the alkylating reagents used expensive, but the selectivity is also low, the separation process is complex, and the use of organic solvents in the system can easily cause air pollution.

[0006] Furthermore, although Li Chengmin et al. (Master's Thesis, Tianjin University, 2014) used solid acid or ionic liquid catalysis to synthesize and isolate highly selective alkylnaphthalenes from alkylating reagents, followed by sulfonation and condensation neutralization to obtain alkylnaphthalene sulfonate formaldehyde condensates, the selectivity and conversion rate of the catalyst decreased significantly after being reused four times. This indicates that the catalysts in this type of process are easily deactivated by the raw materials and are also very expensive. These drawbacks determine that this type of process is currently difficult to industrialize.

[0007] Therefore, it is of great significance to develop a new type of naphthalene-based dispersant that has excellent suspension rate and thermal storage stability, while also being simple to operate and safe and environmentally friendly in production. Summary of the Invention

[0008] 1. The problem to be solved

[0009] In view of the problem that existing naphthalene-based dispersants have poor performance in practical applications, the present invention provides a new naphthalene-based sulfonate condensate, which is suitable as a dispersant for use in water-dispersible granules and suspensions;

[0010] To address the issue of high raw material and environmental costs associated with existing methods for preparing naphthalene-based dispersants (introducing long-chain alkyl groups), this invention provides a novel method for preparing naphthalene-based sulfonate condensates.

[0011] 2. Technical Solution

[0012] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0013] The first aspect of this invention provides a method for preparing naphthalene sulfonate condensates, comprising the steps of:

[0014] 1) Prepare a sulfonation solution containing naphthalenesulfonic acid;

[0015] 2) The sulfonated liquid is first contacted and reacted with the alkyl aldehyde, and then contacted and reacted with the formaldehyde to obtain a condensation liquid;

[0016] 3) The condensation solution is subjected to a neutralization reaction to obtain the naphthalene sulfonate condensate;

[0017] The alkyl aldehydes mentioned do not include formaldehyde.

[0018] It should be noted that in step 2), the alkyl aldehyde must be added first for reaction (to obtain the alkyl hydroxyl intermediate), and formaldehyde must be added later for reaction (to react with the remaining naphthalene sulfonic acid to form an intermediate). If a mixture of alkyl aldehyde and formaldehyde is added at the same time, or if formaldehyde is added first for reaction and then alkyl aldehyde is added for reaction, the highly reactive formaldehyde will directly condense and consume naphthalene sulfonic acid after reaction. After this step of naphthalene sulfonic acid consumption, the proportion of alkyl naphthalene consumed when the less reactive alkyl aldehyde reacts with the remaining naphthalene sulfonic acid will be greatly reduced, or even the less reactive alkyl aldehyde will no longer be able to react with naphthalene sulfonic acid, thus failing to achieve the pre-designed alkyl chain incorporation ratio.

[0019] Furthermore, it will also lead to a significant reduction in the number of rings in the final condensate, affecting its application effect.

[0020] According to any embodiment of the first aspect of the present invention, the naphthalene derivative includes naphthalene and methylnaphthalene.

[0021] According to any embodiment of the first aspect of the present invention, the alkyl aldehyde comprises any one or more of acetaldehyde, propionaldehyde, butylaldehyde, pentylaldehyde, hexylaldehyde, heptylaldehyde, octylaldehyde, nonylaldehyde, and decylaldehyde;

[0022] According to any embodiment of the first aspect of the present invention, the alkyl aldehyde comprises any one, two, or three of acetaldehyde, propionaldehyde, and butylaldehyde.

[0023] As described herein, from the perspective of ensuring a homogeneous condensation reaction and / or minimizing steric hindrance and increasing product reactivity, acetaldehyde, propionaldehyde, or butylaldehyde are preferred. These acetaldehyde, propionaldehyde, or butylaldehyde exhibit relatively good water solubility, thus ensuring a homogeneous condensation reaction. Furthermore, they have relatively short carbon chains, minimal steric hindrance, and high reactivity. All of these factors ensure that the condensation reaction efficiency is not affected.

[0024] According to any embodiment of the first aspect of the present invention, the molar ratio of naphthalenesulfonic acid, alkyl aldehyde and formaldehyde is 1.0:(0.2-0.8):(0.2-0.8).

[0025] According to any embodiment of the first aspect of the present invention, the sulfonation liquid has an acidity of 20-24% and a temperature of 90-100°C.

[0026] According to any embodiment of the first aspect of the present invention, in step 2),

[0027] The reaction time for adding alkyl aldehydes is 2–4 hours;

[0028] The reaction time for adding formaldehyde is 8 to 10 hours.

[0029] According to any embodiment of the first aspect of the present invention, in step 3),

[0030] The neutralization reaction is carried out at a temperature of 60–80°C.

[0031] The pH value after the neutralization reaction is 7-9.

[0032] According to any embodiment of the first aspect of the present invention, step 1) includes contacting a naphthalene compound having a naphthalene skeleton with a sulfonating agent and heating it to 140-160°C under stirring.

[0033] Then, keep it at a temperature of 4-6 hours to obtain the sulfonated liquid.

[0034] In any embodiment of the first aspect of the invention, the naphthalene compound comprises naphthalene and / or methylnaphthalene.

[0035] According to any embodiment of the first aspect of the present invention, the molar ratio of the naphthalene compound having a naphthalene skeleton to the sulfonating agent is 1.0:(1.0-1.1).

[0036] According to any embodiment of the first aspect of the present invention, the sulfonating agent comprises any one, two, or three of sulfuric acid, sulfur trioxide, and fuming sulfuric acid;

[0037] The sulfuric acid has a mass concentration of 98%.

[0038] In any embodiment of the first aspect of the present invention, in step 3), a neutralizing agent is added to carry out a neutralization reaction;

[0039] The neutralizing agent comprises an alkali metal hydroxide, preferably sodium hydroxide or potassium hydroxide.

[0040] According to any embodiment of the first aspect of the present invention, in step 3), a neutralizing agent is added to cause the condensate to undergo a neutralization reaction to obtain a neutralization reaction product (pH = 7-9);

[0041] The neutralization reaction product was dried to obtain the naphthalene sulfonate condensate.

[0042] As described herein, the primary purpose of "drying" is to remove moisture. Based on this, existing known drying methods can be used, such as oven drying, freeze drying, natural drying, spray drying, etc.; spray drying is preferred.

[0043] According to any embodiment of the first aspect of the present invention, the naphthalene sulfonate condensate has a structural formula as shown in formula (1):

[0044]

[0045] In the formula,

[0046] The value of n is 4 to 10, preferably 5 to 8.

[0047] R1 represents an alkyl group from C1 to C9.

[0048] It should be noted that the connection position of R1 is located on the bridging alkyl carbon of two adjacent naphthalene rings, and the connected methylene carbon chain can rotate in multidimensional space, so that the alkyl chain of the naphthalene sulfonate condensate provided by the present invention can generate greater steric hindrance.

[0049] In any embodiment of the first aspect of the present invention, R1 represents methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, or nonyl.

[0050] In any embodiment of the first aspect of the invention, R1 represents ethyl, propyl, or butyl.

[0051] According to any embodiment of the first aspect of the present invention, the compound represented by formula (1) is obtained by condensation of the compound represented by formula (2) and the compound represented by formula (3) in a solvent at 90 to 100°C for 8 to 10 hours.

[0052]

[0053] In the formula, R2, R3, and R4 independently represent hydrogen, C1 to C2, respectively. 10 Alkyl groups.

[0054] According to any embodiment of the first aspect of the present invention, R2, R3, and R4 each independently represent hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, or nonyl.

[0055] According to any embodiment of the first aspect of the present invention, R2, R3, and R4 each independently represent hydrogen, methyl, ethyl, propyl, or butyl.

[0056] According to any embodiment of the first aspect of the present invention, the compound represented by formula (2) is either the compound represented by formula (4) or the compound represented by formula (5);

[0057]

[0058] In the formula, R2 represents C1 to C2. 10 Alkyl groups.

[0059] According to any embodiment of the first aspect of the present invention, the compound represented by formula (3) is either the compound represented by formula (6) or the compound represented by formula (7);

[0060]

[0061] In the formula, R3 and R4 independently represent C1 to C2. 10 Alkyl groups.

[0062] The naphthalene sulfonate condensate described in any embodiment of the first aspect of the present invention is applied to pesticide formulations.

[0063] The naphthalene sulfonate condensate described in any embodiment of the first aspect of the present invention can be used as an aqueous suspension, water-dispersible granule, dry suspension or wettable powder in pesticide formulations.

[0064] A second aspect of the present invention provides a surfactant comprising the naphthalene sulfonate condensate as described in any embodiment of the first aspect of the present invention.

[0065] In any embodiment of the second aspect of the present invention, the surfactant is a naphthalene sulfonate condensate as described in any embodiment of the first aspect of the present invention.

[0066] 3. Intentional effect

[0067] (1) Unlike existing naphthalene sulfonate condensates which introduce alkyl groups into the chain by preparing alkyl naphthalene sulfonic acid monomers, the method for preparing naphthalene sulfonate condensates provided by this invention introduces alkyl groups directly and effectively into the condensation chain structure by first adding alkyl aldehydes and then adding formaldehyde during condensation. The operation is simple, does not require separate preparation of alkyl naphthalene sulfonic acids, does not generate acidic wastewater, and the overall preparation process is simple, efficient, and safe, with excellent development prospects.

[0068] (2) Based on the preparation method of naphthalene sulfonate condensates provided by the present invention, the prepared naphthalene sulfonate condensates have C1-C9 alkyl chains linked on the bridging alkyl carbons of two adjacent naphthalene rings, and the length of the alkyl chains is adjusted; based on this:

[0069] On the one hand, the lipophilic and hydrophilic ratios and steric hindrance of the product can be well adjusted, thereby adjusting the dispersion effect in water-dispersible granules and suspensions when used as a dispersant, and optimizing the various performance indicators of the prepared water-dispersible granules and / or suspensions.

[0070] On the other hand, the alkyl chain provided by the present invention is located on the bridging alkyl carbon of two adjacent naphthalene rings. The bridging methylene carbon chain can rotate in multidimensional space, so that the alkyl chain of the naphthalene sulfonate condensate provided by the present invention can generate greater steric hindrance. When applied to pesticide formulations, it can better prevent the aggregation of pesticide molecules, thereby ensuring the dispersion effect and making the system more stable.

[0071] In existing publicly disclosed naphthalene sulfonate condensates, the alkyl chains are all on the naphthalene ring. Due to the planar structure of the aromatic ring, the methylene carbon chain of the alkyl chain attached to the naphthalene ring can only be in the same plane as the naphthalene ring. Based on this, the steric hindrance effect that the alkyl chain can exert is limited.

[0072] (4) Based on the preparation method of naphthalene sulfonate condensate provided by the present invention, the prepared naphthalene sulfonate condensate is used as a dispersant in pesticide water-dispersible granules or suspensions. Under the combined action of the electrostatic repulsion of the hydrophilic sulfonic acid group, the dispersion force and steric hindrance of the naphthalene ring and alkyl hydrophobic group, and the steric hindrance generated by its own macromolecular structure, the smoothness of pesticide formulation processing, high suspension rate and storage stability are guaranteed. As a dispersant, it can be used in high-concentration pesticide water-dispersible granules and suspensions. The formulation has the advantages of high suspension rate, good thermal storage stability and inhibition of particle size growth. Attached Figure Description

[0073] Figure 1 The 1H NMR spectrum of the naphthalene sulfonate condensate prepared in Example 2;

[0074] Figure 2 The 1H NMR spectrum of the naphthalene sulfonate condensate prepared in Comparative Example 1;

[0075] Figure 3 The infrared spectrum of the naphthalene sulfonate condensate prepared in Example 2;

[0076] Figure 4 The infrared spectrum of the naphthalene sulfonate condensate prepared in Comparative Example 1 is shown. Detailed Implementation

[0077] This disclosure will be more readily understood by referring to the following description, taken in conjunction with the accompanying drawings and examples, all of which form part of this disclosure. It should be understood that this disclosure is not limited to the specific products, methods, conditions, or parameters described and / or illustrated herein. Furthermore, the terminology used herein is for the purpose of describing particular embodiments by way of example only and is not intended to be limiting, unless otherwise stated.

[0078] It should also be understood that, for clarity, certain features of this disclosure may be described herein in the context of individual embodiments, but may also be provided in combination with each other in individual embodiments. That is, unless obviously incompatible or specifically excluded, each individual embodiment is considered to be combinable with any other embodiment, and such combination is considered to represent another different embodiment. Conversely, for brevity, various features of this disclosure described in the context of individual embodiments may also be provided individually or in any sub-combination. Finally, while a particular embodiment may be described as part of a series of steps or part of a more general structure, each step or substructure may also be considered an independent embodiment in itself.

[0079] Unless otherwise stated, it should be understood that each individual element in the list and each combination of individual elements in the list will be interpreted as a different embodiment. For example, a list of embodiments denoted as "A, B, or C" should be interpreted as including embodiments "A", "B", "C", "A or B", "A or C", "B or C", or "A, B, or C".

[0080] In this disclosure, the singular forms of the articles “a,” “one,” and “the” also include the corresponding plural references, and references to a particular value include at least that particular value, unless the context clearly indicates otherwise. Thus, for example, a reference to “substance” is a reference to at least one of such substance and its equivalents.

[0081] Ordinal terms such as “first” and “second” may be used to describe various components or fluids, but these components and fluids are not limited by these terms. Therefore, without departing from the teachings of this disclosure, these terms are used only to distinguish one component / fluid from another.

[0082] When an item is described using the combined terms “...and / or ...", the description should be understood to include any one of the listed items and all combinations thereof.

[0083] Generally, the use of the term "about" indicates an approximation that can vary depending on the desired characteristics obtained from the disclosed subject matter and will be interpreted in a context-dependent manner based on function. Therefore, those skilled in the art will be able to interpret a degree of difference on a case-by-case basis. In some cases, the number of significant figures used when expressing a particular value can be a representative technique for determining the difference allowed by the term "about." In other cases, a gradient within a range of values ​​can be used to determine the range of differences allowed by the term "about." Furthermore, all ranges in this disclosure are inclusive and composable, and references to values ​​described within a range include every value within that range.

[0084] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terms used herein and / or include any and all combinations of one or more of the associated listed items.

[0085] The method for preparing the naphthalene sulfonate condensate provided in the following embodiments specifically includes the following steps:

[0086] (1) Sulfonation reaction: Add a naphthalene compound with a naphthalene skeleton and a sulfonating agent (the molar ratio of the naphthalene compound with the naphthalene skeleton to the sulfonating agent is 1.0:(1.0-1.1)), heat to 140-160℃ under stirring, and keep the reaction at this temperature for 4-6 hours to prepare a sulfonated liquid containing the compound shown in formula (A) below.

[0087]

[0088] (2) Condensation reaction: The temperature of the above sulfonation liquid is reduced to 90-100℃, water is added to adjust the acidity to 20-24%, and then an alkyl aldehyde aqueous solution is added. After the reaction is kept at the temperature (as shown in reaction formulas (Ⅰ) and (Ⅱ)) for 2-4 hours, an formaldehyde aqueous solution is added and the reaction is kept at the temperature (as shown in reaction formulas (Ⅲ) to (Ⅴ)) for 8-10 hours to obtain a condensation liquid. The compound shown in formula (2-1) or formula (2-1) in the condensation liquid undergoes dehydration condensation with the compound shown in formula (2-3) or formula (2-4) to continuously grow into a high molecular weight condensate; or the compounds shown in formula (2-3) and formula (2-4) undergo dehydration condensation to continuously grow into a high molecular weight condensate (as shown in reaction formula (Ⅵ)).

[0089] The molar ratio of naphthalene compounds, alkyl aldehydes and formaldehyde is 1.0:(0.2-0.8):(0.2-0.8).

[0090]

[0091]

[0092] (3) Neutralization reaction: Lower the temperature of the condensate obtained above to 60-80℃, add alkali metal hydroxide to carry out neutralization reaction, and control the temperature at <90℃ to obtain neutralization reaction product with pH=7-8;

[0093] (4) Post-processing: The above neutralized product, sodium naphthalene sulfonate formaldehyde condensate, is pumped to an airflow spray drying tower for spray drying, and then separated by secondary cyclone separation to obtain the naphthalene sulfonate condensate product as shown in formula (1).

[0094]

[0095] The present invention will be further illustrated below with reference to specific embodiments, but these embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field. The essential features and significant effects of the present invention can be seen from the following embodiments. The described embodiments are some, but not all, embodiments of the present invention, and therefore do not limit the present invention in any way. Any non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are within the protection scope of the present invention.

[0096] Example 1

[0097] The naphthalene sulfonate condensate provided in this embodiment has the following structural formula (1-1):

[0098]

[0099] An illustrative method for preparing naphthalene sulfonate condensates provided in this embodiment is as follows:

[0100] (1) Sulfonation reaction: First, add 64g of refined naphthalene and 55g of concentrated sulfuric acid with a mass concentration of 98% in sequence. Under stirring, heat to 150℃ and keep the reaction at this temperature for 4h to prepare sulfonated liquid.

[0101] (2) Condensation reaction: The temperature of the above sulfonated liquid was lowered to 100℃ and kept at the temperature. Water was added to adjust the acidity to 22%. Then 27.5g of acetaldehyde aqueous solution with a mass concentration of 40% was added. After reacting at 100℃ for 3 hours, 20g of formaldehyde aqueous solution with a mass concentration of 37% was added. After reacting at the temperature for 10 hours, the condensation liquid was obtained.

[0102] (3) Neutralization reaction: Lower the temperature of the condensate obtained above to 80°C, add sodium hydroxide to carry out the neutralization reaction, and control the temperature at <90°C to obtain the neutralization reaction product with pH=8;

[0103] (4) Post-processing: The above-mentioned neutralized product, sodium naphthalene sulfonate formaldehyde condensate, is pumped to an airflow spray drying tower for spray drying. After that, it is separated by a second cyclone to obtain the yellow sodium naphthalene sulfonate-acetaldehyde-formaldehyde condensate product with the structure shown in (1-1) above. The inlet air temperature in the spray drying tower is 200℃ and the outlet air temperature is 80℃.

[0104] Example 2

[0105] The naphthalene sulfonate condensate provided in this embodiment has the following structural formulas (1-2):

[0106]

[0107] An illustrative method for preparing naphthalene sulfonate condensates provided in this embodiment is as follows:

[0108] (1) Sulfonation reaction: First, add 64g of refined naphthalene and 55g of concentrated sulfuric acid with a mass concentration of 98% in sequence. Under stirring, heat to 150℃ and keep the reaction at this temperature for 4h to prepare sulfonated liquid.

[0109] (2) Condensation reaction: The temperature of the above sulfonated liquid was lowered to 100℃, water was added to adjust the acidity to 24%, and then 11g of acetaldehyde aqueous solution with a mass concentration of 40% was added. After the reaction was kept at the temperature for 2 hours, 32g of formaldehyde aqueous solution with a mass concentration of 37% (16.24g) was added. After the reaction was kept at the temperature for 10 hours, the condensation liquid was obtained.

[0110] (3) Neutralization reaction: Lower the temperature of the condensate obtained above to 80°C, add sodium hydroxide to carry out the neutralization reaction, and control the temperature at <90°C to obtain the neutralization reaction product with pH=8;

[0111] (4) Post-processing: The above-mentioned neutralized product, sodium naphthalene sulfonate formaldehyde condensate, is pumped to an airflow spray drying tower for spray drying. After secondary cyclone separation, the brownish-yellow sodium naphthalene sulfonate-acetaldehyde-formaldehyde condensate product is obtained. The inlet air temperature in the spray drying tower is 200℃ and the outlet air temperature is 80℃.

[0112] like Figure 1 The figure shows the proton NMR spectrum of the product synthesized in Example 2. Chemical shifts δ2.5-2.59 correspond to the CH3 hydrogen at position 1, chemical shift 4.36 corresponds to the CH hydrogen at position 2, chemical shift δ4.79 corresponds to the CH2 hydrogen at position 3, and chemical shifts δ7-9.5 correspond to the hydrogen on the naphthalene ring. This indicates that the reaction yielded the target product, a naphthalene sulfonate condensate as shown in formulas (1-2).

[0113] like Figure 3 The image shows the infrared spectrum of the product synthesized in Example 2. As can be seen from the image, the product has a wavelength of 3438 cm⁻¹. -1 There is a large, broad absorption peak, which is the absorption peak of the -OH stretching vibration of the -SO3H group in the sulfonated product, at 3051 cm⁻¹. -1 The absorption peak is the Ar-H stretching vibration of the naphthalene ring, 2865–2920 cm⁻¹. -1 These are characteristic absorption peaks for methylene and methyl groups, 1650–1450 cm⁻¹. -1 The absorption peaks are skeletal absorption peaks of the naphthalene ring, ranging from 850 to 684 cm⁻¹. -1 It is an out-of-plane bending vibration of the naphthalene ring. 1444cm -1 This is the absorption peak of the bending vibration of the C-H bond in the methylene group. 1054~1187cm -1It is the S=O stretching vibration frequency of the sulfonate. This indicates that the reaction yields the target product, a naphthalene sulfonate condensate as shown in formulas (1-2).

[0114] Example 3

[0115] The naphthalene sulfonate condensate provided in this embodiment has the following structural formulas (1-3):

[0116]

[0117] An illustrative method for preparing naphthalene sulfonate condensates provided in this embodiment is as follows:

[0118] (1) Sulfonation reaction: First, add 64g of refined naphthalene and 50g of concentrated sulfuric acid with a mass concentration of 98% in sequence. Under stirring, the temperature is raised to 160℃ and kept at the temperature for 5h to prepare sulfonated liquid.

[0119] (2) Condensation reaction: The temperature of the above sulfonated liquid was lowered to 90°C, water was added to adjust the acidity to 20%, and then 44g of acetaldehyde aqueous solution with a mass concentration of 40% was added. After the reaction was kept at the temperature for 4 hours, 8g of formaldehyde aqueous solution with a mass concentration of 37% was added. After the reaction was kept at the temperature for 10 hours, the condensation liquid was obtained.

[0120] (3) Neutralization reaction: Lower the temperature of the condensate obtained above to 80°C, add sodium hydroxide to carry out the neutralization reaction, and control the temperature at <90°C to obtain the neutralization reaction product with pH=8;

[0121] (4) Post-processing: The above-mentioned neutralized product, sodium naphthalene sulfonate formaldehyde condensate, is pumped to an airflow spray drying tower for spray drying. After secondary cyclone separation, the brownish-yellow sodium naphthalene sulfonate-acetaldehyde-formaldehyde condensate product is obtained. The inlet air temperature in the spray drying tower is 200℃ and the outlet air temperature is 80℃.

[0122] Example 4

[0123] The naphthalene sulfonate condensate provided in this embodiment has the following structural formulas (1-4):

[0124]

[0125] The preparation method of the naphthalene sulfonate condensate provided in this embodiment is basically the same as that in Example 1, except that 64g of refined naphthalene in Example 1 is replaced with 71g of methyl naphthalene, while other operating conditions remain unchanged.

[0126] Example 5

[0127] The naphthalene sulfonate condensate provided in this embodiment has the following structural formulas (1-5):

[0128]

[0129] The preparation method of the naphthalene sulfonate condensate provided in this embodiment is basically the same as that in Example 1, except that the neutralizing agent sodium hydroxide in Example 1 is replaced with potassium hydroxide, while other operating conditions remain unchanged.

[0130] Example 6

[0131] The naphthalene sulfonate condensate provided in this embodiment has the following structural formulas (1-6):

[0132]

[0133] The preparation method of the naphthalene sulfonate condensate provided in this embodiment is basically the same as that in Example 1, except that the 27.5g of acetaldehyde aqueous solution with a mass concentration of 40% in Example 1 is replaced with 14.5g of propionaldehyde, while other operating conditions remain unchanged.

[0134] Example 7

[0135] The naphthalene sulfonate condensate provided in this embodiment has the following structural formulas (1-7):

[0136]

[0137] The preparation method of the naphthalene sulfonate condensate provided in this embodiment is basically the same as that in Example 1, except that the 27.5g of acetaldehyde aqueous solution with a mass concentration of 40% in Example 1 is replaced with 18g of butyraldehyde, while other operating conditions remain unchanged.

[0138] Example 8

[0139] The naphthalene sulfonate condensate provided in this embodiment has the following structural formulas (1-8):

[0140]

[0141] The preparation method of the naphthalene sulfonate condensate provided in this embodiment is basically the same as that in Example 2, except that the 11g of acetaldehyde aqueous solution with a mass concentration of 40% in Example 2 is replaced with 5.8g of propionaldehyde, while other operating conditions remain unchanged.

[0142] Example 9

[0143] The naphthalene sulfonate condensate provided in this embodiment has the following structural formulas (1-9):

[0144]

[0145] The preparation method of the naphthalene sulfonate condensate provided in this embodiment is basically the same as that in Example 2, except that the 11g of acetaldehyde aqueous solution with a mass concentration of 40% in Example 2 is replaced with 7.2g of butyraldehyde, while other operating conditions remain unchanged.

[0146] Example 10

[0147] The naphthalene sulfonate condensate provided in this embodiment has the following structural formulas (1-10):

[0148]

[0149] The preparation method of the naphthalene sulfonate condensate provided in this embodiment is basically the same as that in Example 2, except that the 11g of acetaldehyde aqueous solution with a mass concentration of 40% in Example 2 is replaced with 8.6g of pentanal, while other operating conditions remain unchanged.

[0150] Example 11

[0151] The naphthalene sulfonate condensate provided in this embodiment has the following structural formulas (1-11):

[0152]

[0153] The preparation method of the naphthalene sulfonate condensate provided in this embodiment is basically the same as that in Example 2, except that the 11g of acetaldehyde aqueous solution with a mass concentration of 40% in Example 2 is replaced with 10g of hexaldehyde, while other operating conditions remain unchanged.

[0154] Example 12

[0155] The naphthalene sulfonate condensate provided in this embodiment has the following structural formulas (1-12):

[0156]

[0157] The preparation method of the naphthalene sulfonate condensate provided in this embodiment is basically the same as that in Example 2, except that the 11g of acetaldehyde aqueous solution with a mass concentration of 40% in Example 2 is replaced with 11.4g of heptanal, while other operating conditions remain unchanged.

[0158] Example 13

[0159] The naphthalene sulfonate condensate provided in this embodiment has the following structural formulas (1-13):

[0160]

[0161] The preparation method of the naphthalene sulfonate condensate provided in this embodiment is basically the same as that in Example 2, except that the 11g of acetaldehyde aqueous solution with a mass concentration of 40% in Example 2 is replaced with 12.8g of octanal, while other operating conditions remain unchanged.

[0162] Example 14

[0163] The naphthalene sulfonate condensate provided in this embodiment has the following structural formulas (1-14):

[0164]

[0165] The preparation method of the naphthalene sulfonate condensate provided in this embodiment is basically the same as that in Example 2, except that the 11g of acetaldehyde aqueous solution with a mass concentration of 40% in Example 2 is replaced with 14.2g of nonanal, while other operating conditions remain unchanged.

[0166] Example 15

[0167] The naphthalene sulfonate condensate provided in this embodiment has the following structural formulas (1-15):

[0168]

[0169] The preparation method of the naphthalene sulfonate condensate provided in this embodiment is basically the same as that in Example 2, except that the 11g of acetaldehyde aqueous solution with a mass concentration of 40% in Example 2 is replaced with 15.6g of decanal, while other operating conditions remain unchanged.

[0170] Comparative Example 1

[0171] The naphthalene sulfonate condensate provided in this comparative example has the following structural formula (D-1):

[0172]

[0173] The preparation method of the naphthalene sulfonate condensate provided in this embodiment is basically the same as that in Example 2, except that in step (2): only 40g of formaldehyde aqueous solution with a mass concentration of 37% is added and the reaction is kept at a constant temperature for 10h to obtain the condensate, and no alkyl aldehyde (i.e., acetaldehyde corresponding to Example 2) is added, and other operating conditions remain unchanged.

[0174] like Figure 2 The figure shows the proton NMR spectrum of the synthesized product of Comparative Example 1. Chemical shift δ4.79 corresponds to the CH2 hydrogen at position 3. Chemical shifts δ7-9.5 correspond to the hydrogens on the naphthalene ring. This indicates that the reaction yields the target product, a naphthalene sulfonate condensate as shown in formula (D-1).

[0175] like Figure 4 The image shows the infrared spectrum of the synthesized product from Comparative Example 1. As can be seen from the image, the product exhibits a high infrared spectrum at 3430 cm⁻¹.-1 There is a large absorption peak, which may be the absorption peak of the -OH stretching vibration in the -SO3H group formed after the sulfonation of water and organic raw materials in the product, 3006 cm⁻¹. -1 It is the absorption peak of the Ar-H stretching vibration of the naphthalene ring, at 2878 cm⁻¹. -1 The peak is a characteristic absorption peak of the methylene group, and its size is smaller than that of Example 2, indicating the absence of methyl groups; 1650–1450 cm⁻¹ -1 This is the skeletal absorption peak of the naphthalene ring. 850–684 cm⁻¹ -1 This is an out-of-plane bending vibration of the naphthalene ring, and the infrared spectrum structural identification is consistent with the reference. 1444cm -1 This is the absorption peak of the bending vibration of the C-H bond in the methylene group. 1035~1188cm -1 This is the S=O stretching vibration frequency of the sulfonate. This indicates that the reaction yields the target product, a naphthalene sulfonate condensate as shown in formula (D-1).

[0176] Comparative Example 2

[0177] The naphthalene sulfonate condensate provided in this comparative example has the following structural formula (D-2):

[0178]

[0179] The preparation method of the naphthalene sulfonate condensate provided in this embodiment is basically the same as that in Example 2, except that: 11g of acetaldehyde aqueous solution with a mass concentration of 40% and 32g of formaldehyde aqueous solution with a mass concentration of 37% are prepared in advance, and then the two are mixed to form a mixed aqueous solution of acetaldehyde and formaldehyde.

[0180] In step (2), after the acidity is adjusted, 11g of mixed aqueous solution is added first, and after the reaction is kept warm for 2 hours, 32g of mixed aqueous solution is added, and the reaction is kept warm for 10 hours to obtain the condensate.

[0181] Comparative Example 3

[0182] The naphthalene sulfonate condensate provided in this embodiment has the following structural formula (D-3):

[0183]

[0184] The preparation method of the naphthalene sulfonate condensate provided in this embodiment is basically the same as that in Example 2, except that: in step (2), after the acidity is adjusted, 32g of formaldehyde aqueous solution with a mass concentration of 37% is added first, and after the reaction is kept warm for 2 hours, 11g of acetaldehyde aqueous solution with a mass concentration of 40% is added, and the reaction is kept warm for 10 hours to obtain the condensate.

[0185] Comparative Example 4

[0186] A method for preparing a naphthalene sulfonate-alkyl naphthalene sulfonate-formaldehyde condensate specifically includes the following steps:

[0187] (1) Alkylation reaction: First, add 64g of refined naphthalene, 13g of isopropanol and 5g of concentrated sulfuric acid with a mass concentration of 98% in sequence; then, under stirring, raise the temperature to 85℃ and keep the reaction for 4h to prepare a mixture of naphthalene and alkylnaphthalene. The ratio of naphthalene to isopropylnaphthalene in the mixture was 60:40 as detected by high performance liquid chromatography.

[0188] (2) Sulfonation reaction: Add 50g of concentrated sulfuric acid with a mass concentration of 98% to the above mixture of naphthalene and alkyl naphthalene, heat to 160℃ under stirring, keep the temperature for 5h, and then add water to adjust the acidity to 22% to prepare sulfonated solution.

[0189] (3) Condensation reaction: The temperature of the above sulfonated liquid was lowered to 100℃, and 14.5g of propionaldehyde was added, followed by 20g of formaldehyde aqueous solution with a mass concentration of 37%. The reaction was kept at the temperature for 4h to obtain the condensation liquid.

[0190] (4) Neutralization reaction: Same as in Example 6;

[0191] (5) Post-processing, same as in Example 6.

[0192] Example 16

[0193] The naphthalene sulfonate alkyl aldehyde formaldehyde condensates (1-1) to (1-15) prepared in Examples 1-15 of the present invention were used as experimental groups, the naphthalene sulfonate alkyl aldehyde formaldehyde condensates D1 to D3 prepared in Comparative Examples 1-4 were used as control groups 1-4, and the similar product D425 (AkzoNobel) was used as control group 5. 80% dimethomorph water-dispersible granules (hereinafter referred to as 80% dimethomorph WDG) were prepared by extrusion granulation as dispersants, corresponding to experimental groups 1-15 and control groups 1-5.

[0194] The 80wt% dimethomorph WDG contains the following components by mass percentage: 81.6% dimethomorph technical grade (98% purity), 5% dispersant, 3% sodium dodecyl sulfate wetting agent, 2% ammonium sulfate disintegrant, and corn starch to make up 100%.

[0195] The suspension rate, disintegration, foaming height, and suspension rate (5452℃, 14 days) of the 80% dimethomorph WDG prepared separately were tested. Specific tests included:

[0196] 1. Suspension rate determination:

[0197] The suspension rate was determined according to the GB / T14825 method.

[0198] 2. Disintegration test:

[0199] In a 25℃ constant temperature bath, take a 100mL stoppered graduated cylinder (inner height 22.5cm, inner diameter 28mm) and add 90mL of distilled water; add 0.5g of water-dispersible granule sample into the graduated cylinder, clamp the middle of the stoppered graduated cylinder, plug the mouth of the graduated cylinder, and rotate it around the center at a speed of 8r / min until the sample is completely disintegrated and dispersed in the graduated cylinder. Record the disintegration time. The disintegration property is tested by the length of the disintegration time, which is generally specified to be less than 3min.

[0200] 3. Wettability test:

[0201] At 25℃, add 500mL of standard hard water (calcium and magnesium ion concentration 342g / L) to a 500mL graduated cylinder. Weigh 1.0g of the preparation and quickly pour it into the graduated cylinder without stirring. Immediately use a stopwatch to record the time when 99% of the sample sinks to the bottom of the graduated cylinder. This is the wetting time. Use the wetting time to test the wettability of the water-dispersible granules.

[0202] 4. Foaming property test:

[0203] Add 95 mL of standard hard water to a 100 mL graduated stoppered cylinder at 25°C. The volume between the 100 mL mark and the bottom of the stopper should be 25–40 mL. Weigh 1.0 g of the water-dispersible granule sample and add it to the graduated cylinder. Then add standard hard water to bring the volume up to the 100 mL mark. Stopper the cylinder and invert it 30 times, completing each inversion within 2 seconds. Let it stand for 5 minutes and record the foam volume.

[0204] 5. Thermal storage stability test:

[0205] The water-dispersible granules to be tested are packed into ampoules, 5.0g per ampoule, sealed, and placed in an oven at 54℃-52℃ for 14 days. The corresponding heat storage suspension rate of WDG is then measured according to the method of GB / T19136-2003.

[0206] The test results are shown in Table 1 below:

[0207] Table 1. Properties test results for each group

[0208]

[0209]

[0210] Example 17

[0211] The naphthalene sulfonate alkyl aldehyde formaldehyde condensates prepared in Examples 1-15 of the present invention were used as experimental groups, comparative examples 1-4 were used as control groups 1-4, and similar product D425 (AkzoNobel) was used as control group 5. 40% thiamethoxam SC was prepared by sand milling, corresponding to experimental groups 1-15 and control groups 1-5.

[0212] Preparation process of 4wt% thiamethoxam SC: Weigh a certain amount of dispersant, antifreeze ethylene glycol, magnesium aluminum silicate, and distilled water into a self-made round-bottom sand mill flask. After the dispersant is stirred and dissolved, add thiamethoxam technical and zirconia beads. Sand mill at 3000 r / min under cooling water conditions. After observing that the particle size is less than 5 μm, add xanthan gum and sand mill for a while, then filter to remove the zirconia beads, thus obtaining 40% thiamethoxam SC.

[0213] 40wt% thiamethoxam SC comprises the following components by weight percentage: 40.8% thiamethoxam technical grade (98% purity), 2% dispersant SP-27001, 6% self-made naphthalene sulfonate-alkyl naphthalene sulfonate-formaldehyde condensate dispersant, 4% antifreeze ethylene glycol, 0.14% xanthan gum, 0.5% magnesium aluminum silicate, and distilled water to make up to 100%.

[0214] The 40% thiamethoxam SC prepared separately was tested for suspension rate, suspension rate (5452℃, 14 days), particle size, and particle size (5452℃, 14 days). Specific detection methods included:

[0215] 1. Suspension rate determination:

[0216] The suspension rate was determined according to the method in GB / T14825-2006.

[0217] 2. Thermal storage stability test:

[0218] The SC to be tested is packed into ampoules, 10.0g per ampoule, sealed, and placed in an oven at 54℃-52℃ for 14 days. After heat storage, the corresponding heat storage suspension rate of SC is measured.

[0219] 3. Particle size determination:

[0220] The average particle size of the active ingredient in the suspension samples was determined using a laser particle size analyzer. Each sample was measured three times, and the average value was taken.

[0221] The test results are shown in Table 2 below:

[0222] The test results are shown in Table 2 below:

[0223] Table 2. Properties test results for each group

[0224]

[0225] The data in Tables 1 and 2 above clearly show that:

[0226] Compared to the sodium naphthalenesulfonate formaldehyde condensate prepared from naphthalene and formaldehyde in Comparative Example 1, the naphthalene sulfonate condensate prepared by the methods disclosed in Examples 1-15 of this invention, when used to prepare 80% dimethomorpholine WDG, significantly improves the evaluation indicators such as system stability, thermal storage stability, and disintegration rate; when used to prepare 40% thiamethoxam SC, it significantly improves the evaluation indicators such as suspension rate, thermal storage stability, and inhibition of particle size growth. The performance of the excipients in both formulations is comparable to that of the imported product D425 on the market, with some indicators even exceeding those of the imported product. This demonstrates that the methods disclosed in this invention simplify the steps, reduce environmental harm, and achieve the corresponding technical level in the field, exhibiting outstanding substantive characteristics.

[0227] Compared to the sodium naphthalene sulfonate formaldehyde condensates prepared in Comparative Examples 2 and 3, the naphthalene sulfonate condensate prepared by the method disclosed in Example 2 of this invention has a higher alkyl content in the final product due to the addition of alkyl aldehydes in the first step, resulting in greater steric hindrance. When used to prepare 80 wt% dimethomorpholine WDG, it can significantly improve the evaluation indicators such as system stability, thermal storage stability, and disintegration rate; when used to prepare 40 wt% thiamethoxam SC, it can significantly improve the evaluation indicators such as suspension rate, thermal storage stability, and inhibition of particle size growth.

[0228] Compared to the sodium naphthalene sulfonate formaldehyde condensate prepared in Comparative Example 4, the naphthalene sulfonate condensate prepared by the methods disclosed in Examples 1-15 of this invention exhibits greater steric hindrance due to the alkyl groups grafted onto the bridging chain and the rotatable aromatic ring space. Based on this, while maintaining relatively low dispersant usage (5 wt%, 6 wt%), its use in preparing 80 wt% dimethomorpholine WDG significantly improves system stability, thermal storage stability, and other evaluation indicators; its use in preparing 40 wt% thiamethoxam SC significantly improves suspension rate, thermal storage stability, and inhibition of particle size growth.

[0229] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing naphthalene sulfonate condensates for pesticide formulations, characterized in that, Including the following steps: 1) Prepare a sulfonation solution containing naphthalenesulfonic acid; 2) The sulfonated liquid is first contacted and reacted with alkyl aldehyde, and then contacted and reacted with formaldehyde to obtain a condensation liquid; 3) The condensation solution is subjected to a neutralization reaction to obtain the naphthalene sulfonate condensate; The sulfonating liquid comprises: Acidity 20~24%; Temperature 90~100℃; The alkyl aldehydes mentioned do not include formaldehyde; The molar ratio of naphthalenesulfonic acid, alkyl aldehyde, and formaldehyde is 1.0:(0.2~0.8):(0.2~0.8). The naphthalene sulfonate condensate shown has the structural formula as shown in formula (1): （1）； In the formula, The value of n can be 4 to 10; R1 represents an alkyl group from C1 to C9.

2. The method for preparing naphthalene sulfonate condensates for pesticide formulations according to claim 1, characterized in that, The alkyl aldehydes include any one, two, or three of acetaldehyde, propionaldehyde, and butylaldehyde.

3. The method for preparing naphthalene sulfonate condensates for pesticide formulations according to claim 2, characterized in that, In step 2), The reaction time for adding alkyl aldehydes is 2-4 hours; The reaction time for adding formaldehyde is 8-10 hours.

4. The method for preparing naphthalene sulfonate condensates for pesticide formulations according to claim 3, characterized in that, In step 3), the temperature of the neutralization reaction is 60~80℃; The pH value after the neutralization reaction is 7-9.

5. The method for preparing naphthalene sulfonate condensates for pesticide formulations according to any one of claims 1 to 4, characterized in that, Step 1) includes contacting a naphthalene compound with a naphthalene skeleton with a sulfonating agent and heating it to 140-160°C under stirring. Then, keep it at a temperature of 4-6 hours to obtain the sulfonated liquid.

6. The method for preparing naphthalene sulfonate condensates for pesticide formulations according to claim 5, characterized in that, The molar ratio of the naphthalene compound with the naphthalene skeleton to the sulfonating agent is 1.0:(1.0-1.1).

7. The method for preparing naphthalene sulfonate condensates for pesticide formulations according to claim 6, characterized in that, The sulfonating agent includes any one, two, or three of sulfuric acid, sulfur trioxide, and fuming sulfuric acid.

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