A low-foaming surfactant and its preparation method and application

Abstract

The present invention belongs to the technical field of fine chemical industry, and relates to a low-foaming surfactant and a preparation method thereof. The molecular structure of the low-foaming surfactant is generally expressed as follows: #imgabs0# or #imgabs1# wherein n=12, 14, 16, 18, C n H 2n+1 It is a straight chain or branched chain structure. The low-foaming surfactant is prepared from the following raw materials in a molar ratio: the molar ratio of alkyl-1,3-propylene diamine, alcohol solvent, 1,3-propane sultone, trimethylamine, hydrochloric acid, and epichlorohydrin is 1 mol: 14.00-26.00 mol: 1.00-1.20 mol: 1.00-2.30 mol: 1.00-2.30 mol: 1.00-2.30 mol. The synthetic raw materials of the low-foaming surfactant of the present invention are easy to obtain, the production cost is low, and the production process is simple, and it can be used as a low-foaming surfactant or an emulsifier.

Description

Technical Field

[0001] The invention relates to the technical field of fine chemical industry, and in particular to a low-foaming surfactant and a preparation method and application thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] Low-foaming surfactants are surfactants that exhibit low-foaming properties in spray cleaning or other fields of use. The purpose of low foaming is to meet the requirements of the production environment. In the production process of some products, the generation of foam brings adverse effects, so low-foaming or non-foaming surfactants are needed. For example, non-foaming or low-foaming industrial detergents can be used as metal cleaning agents, metal degreasing agents, plastic cleaning agents, etc.

[0004] For example, in the prior art, a study discloses a low-foam multi-effect laundry detergent (Chinese patent CN104804891A), which is made of the following raw materials in parts by weight: 9-16 parts of sodium dodecylbenzene sulfonate, 3-8 parts of cocoyl diethanolamine, 3-5 parts of wormwood essential oil, 6-11 parts of ester quaternary ammonium salt, 5-8 parts of alcohol ether carboxylate, 5-12 parts of fatty alcohol polyoxyethylene ether, 5-11 parts of calcium silicate, 3-6 parts of calcium hydroxide, 8-14 parts of fatty alcohol polyoxyethylene ether, 5-9 parts of alkyl polyglycoside, 2-4 parts of propionate, 3-8 parts of anionic surfactant, 2-6 parts of ethylene oxide, 3-10 parts of citric acid, 6-10 parts of sodium toluenesulfonate, and 2-10 parts of sodium sulfate. There are also studies involving the synthesis methods of heavy oil sulfonates and heavy oil sulfonate surfactants, wherein the synthesis method of heavy oil sulfonates includes a heavy oil sulfonation step, characterized in that: fulvene diesel or a mixture of fulvene diesel and heavy alkylbenzene is mixed into the heavy oil; the synthesis method of heavy oil sulfonate surfactant is characterized in that it includes: adding alkali solution to neutralize the heavy oil sulfonate after aging; after the neutralization is completed, adding mixed alcohol and mixing to obtain the heavy oil sulfonate surfactant.

[0005] The inventors have found that the current research on low-foaming surfactants is mainly focused on the formulation and composition of surfactants, and there are very few single-ingredient low-foaming surfactant products.

[0006] In addition, the sulfonate surfactants are relatively rare and expensive, which limits their wide application, especially low-foaming surfactants. The inventors also found that the existing surfactants still have the disadvantages of poor low-foaming and emulsifying properties and complex preparation processes and methods. Summary of the invention

[0007] In view of the shortcomings of surfactants in the prior art that low-foaming performance and emulsifying performance are still poor, and the preparation process and method are complicated, the present invention discloses a low-foaming surfactant and a preparation method and application thereof. The prepared low-foaming surfactant has good low-foaming performance, emulsifying performance, surface performance, and a simple preparation process.

[0008] Specifically, the present invention is achieved through the following technical solutions:

[0009] In a first aspect, the present invention provides a low-foaming surfactant having the following structure:

[0010]

[0011] Where n = 12, 14, 16, 18, C n H 2n+1 It has a straight chain or branched chain structure.

[0012] The second aspect of the present invention provides a method for preparing a low-foaming surfactant, comprising:

[0013] Synthesize intermediate M1 and intermediate M2, and then mix intermediate M1 and intermediate M2 to react, so as to obtain a low-foaming surfactant;

[0014] The general structural formula of the intermediate M1 is

[0015] C n H 2n+1 NHCH2CH2CH2NHCH2CH2CH2SO3H,

[0016] Where n = 12, 14, 16, 18, C n H 2n+1 It is a straight chain or branched chain structure;

[0017] The structural formula of the intermediate M2 is

[0018]

[0019] The third aspect of the present invention provides a low-foaming surfactant prepared by a method for preparing a low-foaming surfactant.

[0020] In a fourth aspect, the present invention provides a use of a low-foaming surfactant as a low-foaming surfactant or an emulsifier.

[0021] One or more of the above technical solutions have the following beneficial effects:

[0022] (i) The present invention combines sulfonic acid group, quaternary ammonium salt, amino hydrophilic group and lipophilic group with suitable carbon chain length to form a surfactant with a novel structure. Experiments show that the low-foaming performance, emulsifying performance and surface performance of the low-foaming surfactant are better than those of sodium dodecylbenzene sulfonate and others.

[0023] (ii) The main raw material for preparing the low-foaming surfactant of the present invention is alkyl-1,3-propylene diamine (for example, N-hydrogenated tallow-1,3-propylene diamine), which is cheaper and more widely available than the raw materials used for the currently commonly used sulfonate-type surfactants, and has a low production cost.

[0024] (iii) In the prior art, sulfonate surfactants are produced by sulfonation reaction using chlorosulfonic acid, concentrated sulfuric acid, fuming sulfuric acid or sulfur trioxide as sulfonation reagents, which has the disadvantages of high sulfonation reaction temperature, complex preparation process, high process risk and high corrosiveness. The preparation method of the low-foaming surfactant of the present invention has a simple process, and only requires sequential addition of materials and mixing and stirring at a relatively low reaction temperature, without the need for high-temperature reaction, which greatly reduces energy consumption, reduces the difficulty of operation for operators and reduces the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein:

[0026] Figure 1 This is the FTIR spectrum of the intermediate M1 of Example 1 after purification by recrystallization.

[0027] Figure 2 This is the NMR spectrum of the intermediate M1 of Example 1 after purification by recrystallization.

[0028] Figure 3 This is the MS spectrum of the intermediate M1 of Example 1 after purification by recrystallization.

[0029] Figure 4 This is the FTIR spectrum of the product of Example 1 after purification by recrystallization.

[0030] Figure 5 This is the MS spectrum of the product of Example 1 after purification by recrystallization.

[0031] Figure 6 This is the FTIR spectrum of the product of Example 2 after purification by recrystallization.

[0032] Figure 7 This is a graph showing the relationship between surface tension and concentration logarithm of the product of Example 1 after purification by recrystallization.

[0033] Figure 8 This is a graph showing the relationship between surface tension and concentration logarithm of the product of Example 2 after purification by recrystallization. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples without specifying specific conditions are usually carried out under conventional conditions or under conditions recommended by the manufacturer.

[0035] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0036] The inventors have found through long-term research that the current research on low-foaming surfactants is mainly focused on surfactant formulations and compositions, and there are very few single-component low-foaming surfactants.

[0037] Specifically, the present invention is achieved through the following technical solutions:

[0038] In a first aspect, the present invention provides a low-foaming surfactant having the following structure:

[0039]

[0040] Where n = 12, 14, 16, 18, C n H 2n+1 It has a straight chain or branched chain structure.

[0041] The second aspect of the present invention provides a method for preparing a low-foaming surfactant, comprising:

[0042] Synthesize intermediate M1 and intermediate M2, and then mix intermediate M1 and intermediate M2 to react, so as to obtain a low-foaming surfactant;

[0043] The general structural formula of the intermediate M1 is

[0044] C n H 2n+1 NHCH2CH2CH2NHCH2CH2CH2SO3H,

[0045] Where n = 12, 14, 16, 18, C n H 2n+1 It is a straight chain or branched chain structure;

[0046] The structural formula of the intermediate M2 is

[0047]

[0048] When the molar amount of intermediate M2 is less than that of intermediate M1, the product is

[0049]

[0050] When the molar amount of intermediate M2 is between 1 and 2 times the molar amount of intermediate M1, the product is

[0051]

[0052] mixture of

[0053] When the molar amount of intermediate M2 is greater than or equal to twice the molar amount of intermediate M1, the product is

[0054]

[0055] Preferably, the preparation method of the intermediate M1 comprises: dissolving alkyl-1,3-propylene diamine and 1,3-propane sultone in a solvent, reacting to obtain the intermediate M1;

[0056] Preferably, the preparation method of the intermediate M2 comprises: mixing an aqueous solution of trimethylamine, hydrochloric acid and epichlorohydrin, and reacting to obtain the intermediate M2;

[0057] Further preferably, the preparation method comprises:

[0058] 1) mixing alkyl-1,3-propylene diamine, an alcohol solvent and 1,3-propane sultone to react to obtain an intermediate M1;

[0059] 2) mixing trimethylamine aqueous solution, hydrochloric acid and epichlorohydrin, and reacting to obtain intermediate M2;

[0060] 3) The intermediate M2 is added dropwise to the intermediate M1, and the mixture is mixed and reacted to obtain a low-foaming surfactant.

[0061] The experimental temperature and time affect the structural formula and substitution position of the product. In one or more embodiments of the present invention, in step 1), in the preparation of intermediate M1, the reaction temperature of the mixed reaction is 60-80° C. and the reaction time is 3-5 h.

[0062] In one or more embodiments of the present invention, in step 2), in preparing the intermediate M2, the reaction temperature of the mixed reaction is 42° C. and the reaction time is 3 h;

[0063] Or, in step 3), the reaction temperature of the mixed reaction is 60-80° C., and the reaction time is 2-4 h.

[0064] Experiments have shown that the synthesis reaction temperatures of intermediates M1 and M2 are different, which is related to the different raw materials and product structures of the two. If the reaction temperature for synthesizing intermediate M2 is high, the epoxy bond in M2 will be opened. If the reaction temperature for synthesizing intermediate M2 is low, the raw materials will not react. The temperature of the final product generated by the reaction of intermediates M1 and M2 is close to the synthesis temperature of intermediate M1, which helps to break the epoxy bond of intermediate M2 and react with intermediate M1.

[0065] In one or more embodiments of the present invention, the molar ratio of the alkyl-1,3-propylene diamine, alcohol solvent, 1,3-propane sultone, trimethylamine, hydrochloric acid, and epichlorohydrin is 1 mol: 14.00-26.00 mol: 1.00-1.20 mol: 1.00-2.30 mol: 1.00-2.30 mol: 1.00-2.30 mol.

[0066] In one or more embodiments of the present invention, in step 1), in the synthesis of intermediate M1, the alcohol solvent is ethanol or isopropanol with a low carbon number.

[0067] Or, the alkyl-1,3-propylene diamine is at least one selected from dodecyl-1,3-propylene diamine, tetradecyl-1,3-propylene diamine, hexadecyl-1,3-propylene diamine, and octadecyl-1,3-propylene diamine;

[0068] Preferably, the alkyl-1,3-propylene diamine is N-hydrogenated tallow-1,3-propylene diamine.

[0069] In one or more embodiments of the present invention, the following steps are specifically included:

[0070] (1) Dissolve alkyl-1,3-propylene diamine in an alcohol solvent, heat and stir to dissolve, then add 1,3-propane sultone, and after the addition is complete, stir and react at 60-80° C. for 3-5 hours to obtain intermediate M1;

[0071] (2) Take an appropriate amount of trimethylamine aqueous solution, add hydrochloric acid, and then add epichlorohydrin. After the addition of epichlorohydrin is completed, stir and react at 42°C for 3 hours to obtain intermediate M2;

[0072] (3) Add intermediate M2 to intermediate M1 and react at 60-80° C. for 2-4 h to obtain a low-foaming surfactant.

[0073] During the mixing of the two or more reactants, 1,3-propane sultone is added in 3 to 5 times, hydrochloric acid is added in 3 to 5 times, epichlorohydrin is added in 3 to 5 times, and intermediate M2 is added in 3 to 5 times.

[0074] More preferably, 1,3-propane sultone is added in 5 portions, hydrochloric acid is added in 5 portions, epichlorohydrin is added in 5 portions, and intermediate M2 is added in 5 portions.

[0075] In one or more embodiments of the present invention, the method further comprises: a separation and purification process;

[0076] Preferably, the solvent of the synthetic product of step 1) or step 3) is evaporated, and then recrystallized and separated and purified using an organic solvent;

[0077] More preferably, the organic solvent is methanol.

[0078] The third aspect of the present invention provides a low-foaming surfactant prepared by a method for preparing a low-foaming surfactant.

[0079] In a fourth aspect, the present invention provides a use of a low-foaming surfactant as a low-foaming surfactant or an emulsifier.

[0080] For example, in the application of industrial cleaning agents, the generation of foam is not conducive to the control of production processes, and may cause material overflow and environmental pollution. In the application of emulsified asphalt, the generation of foam is not conducive to the transportation of emulsified asphalt.

[0081] The invention uses alkyl-1,3-propylene diamine as the main reaction raw material of the low-foaming surfactant, introduces sulfonic acid group, quaternary ammonium salt and amine group into the molecular structure by adding 1,3-propane sultone, trimethylamine aqueous solution, hydrochloric acid, epichlorohydrin and other raw materials in the synthesis step of the low-foaming surfactant, thereby improving the low-foaming property, emulsification property and surface property.

[0082] The present invention will be further described in detail below in conjunction with specific embodiments. It should be noted that the specific embodiments are intended to explain the present invention rather than to limit it.

[0083] Example 1

[0084] (1) Preparation of low foaming surfactant:

[0085] 1) Add 326.0 g of N-hydrogenated tallow-1,3-propylene diamine and 1100 g of isopropanol to a three-necked flask, and heat and stir to dissolve. Then add 128.2 g of 1,3-propane sultone in 5 portions, and stir at 70°C for 4 hours to obtain intermediate M1.

[0086] The solvent of the synthetic intermediate M1 was evaporated, and then recrystallized and separated and purified three times using methanol, and then analyzed by infrared, nuclear magnetic resonance and mass spectrometry.

[0087] Infrared analysis ( Figure 1 ): 3464cm -1 (Peak 1) is the stretching vibration peak of OH in the sulfonic acid group, 3026 cm -1 (Peak 2) is the secondary amine NH stretching vibration peak, 2920 cm -1 (Peak 3) is the asymmetric stretching vibration absorption peak of methylene, 2854 cm -1 (Peak 4) is the symmetrical stretching vibration peak of methylene, 1465 cm -1 (Peak 5) is the asymmetric bending vibration absorption peak of methylene, 1213 cm -1 (Peak 6) is the stretching vibration absorption peak of CN, 1176 cm -1 (Peak 7) is the symmetric stretching vibration absorption peak of the sulfonic acid group S=O, 1041 cm -1 (Peak 8) is the asymmetric stretching vibration absorption peak of the sulfonic acid group S=O, 723 cm -1 (Peak 9) is the in-plane rocking vibration of methylene, 605 cm -1 (Peak 10) is the stretching vibration absorption peak of SO, 534 cm -1 (Peak 11) is the bending vibration absorption peak of OH in the sulfonic acid group.

[0088] NMR analysis ( Figure 2 ): 1 H NMR (400MHz, CD3OD), δ: 0.875-0.910 (3H, t, J = 7.0Hz, -C H 3),1.219-1.363(30H,s,CH3(C H 2) 15 CH2CH2-),1.540-1.647(2H,m,CH3(CH2) 15 C H 2CH2-),1.863-1.916(2H,m,-NHCH2C H 2CH2NH-),2.005-2.156(2H,m,-CH2C H 2CH2SO3H),2.847-3.024(8H,m,-C H 2NHC H 2CH2C H 2NHC H 2-),3.468-3.476(2H,t,J=1.6Hz,-C H 2SO3H)ppm.

[0089] Mass spectrometry analysis ( Figure 3 ): HRMS(ESI)(positive)m / z:[M+H] + Calcd for C 24 H 53 N2O3S,449.3777; Found 449.3799.

[0090] 2) Add 189.5 g of 33% (mass fraction) trimethylamine aqueous solution into another reactor, add 108.3 g of 36% (mass fraction) hydrochloric acid in 5 portions, and then add 96.1 g of epichlorohydrin in 5 portions, and stir the reaction at 42° C. for 3 h to obtain intermediate M2;

[0091] 3) Add intermediate M2 to intermediate M1 in 5 portions and react at 70°C for 3 hours to obtain a low-foaming surfactant.

[0092] The solvent of the above-mentioned synthetic product was evaporated, and then recrystallized, separated and purified three times using methanol as solvent, and then subjected to infrared and mass spectrometry analysis and detection.

[0093] FTIR analysis (see Figure 4 ): 3441cm -1 (peak 1) is the stretching vibration peak of the hydroxyl group and OH in the sulfonic acid group in the molecule, 3175 cm -1 (peak 2) is the secondary amine NH stretching vibration peak, 2922 cm -1 (peak 3) is the asymmetric stretching vibration absorption peak of methylene, 2851 cm -1 (peak 4) is the symmetrical stretching vibration peak of methylene, 1533 cm -1 (peak 5) is the deformation vibration absorption peak of NH, 1467cm -1 (peak 6) is the asymmetric bending vibration of methylene, 1202 cm -1 (peak 7) is the symmetric stretching vibration absorption peak of the sulfonic acid group S=O, 1043 cm -1 (peak 8) is the asymmetric stretching vibration absorption peak of the sulfonic acid group S=O, 895 cm -1 (peak 9) is the out-of-plane bending vibration absorption peak of methylene, 725 cm -1 (peak 10) is the absorption peak of the methylene in-plane rocking vibration, 611 cm -1 (peak 11) is the stretching vibration absorption peak of SO, 527 cm -1 (peak 12) is the bending vibration absorption peak of OH in the hydroxyl group and sulfonic acid group.

[0094] Mass spectrometry (see Figure 5): HRMS(ESI)(positive)m / z:[M-Cl — ] + Calcd for C 30 H 66 N3O4S,564.4774; Found 564.4759.

[0095] The reaction equation is as follows:

[0096]

[0097]

[0098] Example 2

[0099] (1) Preparation of low foaming surfactant:

[0100] 1) Add 326.0 g of N-hydrogenated tallow-1,3-propylene diamine and 1100 g of isopropanol to a three-necked flask, and heat and stir to dissolve. Then add 128.2 g of 1,3-propane sultone in 5 portions, and stir at 70°C for 4 hours to obtain intermediate M1.

[0101] 2) Add 379.0 g of 33% (mass fraction) trimethylamine aqueous solution into another reactor, add 216.6 g of 36% (mass fraction) hydrochloric acid in 5 portions, and then add 192.2 g of epichlorohydrin in 5 portions, and stir at 42° C. for 3 h to obtain intermediate M2;

[0102] 3) Add intermediate M2 to intermediate M1 in 5 portions and react at 70°C for 3 hours to obtain a low-foaming surfactant.

[0103] The solvent was evaporated from the above-mentioned synthetic product, and then it was recrystallized, separated and purified by methanol for three times, and then analyzed and detected by FTIR.

[0104] FTIR analysis (see Figure 6 ): 3447cm -1 (peak 1) is the stretching vibration peak of the hydroxyl group and OH in the sulfonic acid group in the molecule, 2924 cm -1 (peak 2) is the asymmetric stretching vibration absorption peak of methylene, 2847 cm -1 (peak 3) is the symmetrical stretching vibration peak of methylene, 1468 cm -1 (peak 4) is the asymmetric bending vibration of methylene, 1202 cm -1 (peak 5) is the symmetric stretching vibration absorption peak of sulfonic acid group S=O, 1043 cm -1(peak 6) is the asymmetric stretching vibration absorption peak of the sulfonic acid group S=O, 895 cm -1 (peak 7) is the out-of-plane bending vibration absorption peak of methylene, 723 cm -1 (peak 8) is the absorption peak of the methylene in-plane rocking vibration, 611 cm -1 (peak 9) is the stretching vibration absorption peak of SO, 523 cm -1 (peak 10) is the bending vibration absorption peak of OH in the hydroxyl group and sulfonic acid group.

[0105] The reaction equation is as follows:

[0106]

[0107]

[0108] Experimental Example 1

[0109] In this experimental example, the low-foaming surfactant prepared in Examples 1 to 2 was tested for its anti-foaming performance, and its anti-foaming performance before and after purification was measured respectively.

[0110] Test method: At room temperature, take 10mL of 0.5% sodium dodecylbenzene sulfonate (LBS) aqueous solution and a certain amount of sample and pour them into a 100mL stoppered measuring cylinder, plug it, and record the total foam volume V1 immediately after vigorous shaking for 20 times. The foam suppression value P is calculated according to the following formula, and its value reflects the foam suppression ability of the sample.

[0111] P=(V0-V1) / V0

[0112] Wherein, V0 is the total volume of foam immediately after shaking in the blank test, milliliters; V1 is the total volume of foam immediately after shaking when the sample is added, milliliters.

[0113] Experimental results: The low foaming surfactants prepared in Examples 1 and 2 were compared with OP-10 (a commercially available product). The foam suppression properties of the samples before and after purification and of OP-10 are shown in Tables 1 and 2.

[0114] Table 1 Antifoaming properties of samples and OP-10 before purification

[0115]

[0116] Table 2 Antifoaming properties of each sample and OP-10 after purification

[0117]

[0118] The results show that the low-foaming surfactants prepared in Examples 1 to 2 have good anti-foaming ability before and after purification.

[0119] Experimental Example 2

[0120] In this experimental example, the emulsification ability of the low-foaming surfactant prepared in Examples 1 to 2 was tested to determine its emulsification ability before and after purification.

[0121] Test method: At room temperature, pour 20mL of 0.1% sample aqueous solution and OP-10 aqueous solution and 20mL of liquid paraffin into a 100mL stoppered measuring cylinder, plug the stopper, shake vigorously 5 times and let stand for 1min, repeat 5 times and record the time to separate 10mL of water.

[0122] Experimental results: The low foaming surfactants prepared in Examples 1 and 2 were compared with OP-10. The emulsifying abilities of the samples before and after purification and OP-10 are shown in Table 3.

[0123] Table 3 Emulsification ability of each surfactant

[0124]

[0125] Experiments show that the low-foaming surfactants prepared in Examples 1 and 2 all have good emulsifying ability.

[0126] Experimental Example 3

[0127] In this experimental example, the foaming property and foam stability of the low-foaming surfactant prepared in Examples 1 and 2 were tested, and the foaming property and foam stability of the purified product were determined.

[0128] Test method: Prepare 80mL of an aqueous solution of the purified product with a concentration of 0.001mol / L for later use. Take 20mL of the prepared solution and place it in a 100mL stoppered measuring cylinder and keep it in a water bath at a constant temperature of 25℃ for 10min. Shake the constant temperature solution up and down vigorously 20 times and leave it in the water bath, and immediately record the initial volume of the foam (H0); record the volume of the foam after 5min (H5); the time it takes for the foam volume to decay to half of the initial volume (t 1 / 2 The experimental process was repeated 3 times and the average value was taken.

[0129] Experimental results: The low foaming surfactants prepared in Examples 1 and 2 were compared with sodium dodecylbenzene sulfonate. The foaming properties and foam stability of each sample after purification and sodium dodecylbenzene sulfonate are shown in Table 4.

[0130] Table 4 Foaming and foam stability of each surfactant

[0131]

[0132] The experiment shows that compared with sodium dodecylbenzene sulfonate, the low foaming surfactant prepared in Examples 1-2 has poor foaming property after purification, but good foam stability, which indicates that the surfactant prepared in Examples 1-2 is a low foaming surfactant.

[0133] Experimental Example 4

[0134] The surface tension of the surfactants prepared in Examples 1 and 2 was tested to determine the surface tension and critical micelle concentration (CMC) of the purified samples.

[0135] Methods: An interfacial tension meter was used to prepare a series of surfactant aqueous solutions with different concentrations. The surface tension was measured by the hanging plate method. The surface tension-log c curve was drawn to obtain the critical micelle concentration and the surface tension (γ CMC ).

[0136] Experimental results: The surface tension and concentration logarithmic relationship of the surfactants prepared in Examples 1 to 2 is shown in Figure 7 and Figure 8 It can be seen that the CMC of Example 1 is 1.88×10 -5 mol / L, surface tension at CMC (γ CMC ) is 32.80 mN / m. The CMC of Example 2 is 7.08×10 -6 mol / L, surface tension at CMC (γ CMC ) is 33.10mN / m.

[0137] Comparative Example 1

[0138] Synthesis of surfactants:

[0139] (a) 326.0 g of N-hydrogenated tallow-1,3-propylene diamine and 330 g of isopropanol were added to a three-necked flask, heated with stirring, and 216.8 g of acrylamide was added, and the mixture was reacted at 70° C. for 3 h.

[0140] (b) In another three-necked flask, 245.2 g of sodium bisulfite and 785.4 g of water were added and heated to 75° C. 197.8 g of epichlorohydrin was added dropwise and stirred for 3.5 h to obtain sodium 3-chloro-2-hydroxypropyl sulfonate.

[0141] (c) The sodium sulfonate aqueous solution of step (b) was added dropwise to the product of step (a), and the mixture was reacted at 65° C. for 4 h. The solvent was evaporated, and the mixture was recrystallized three times with anhydrous methanol to obtain a pure product.

[0142] Reaction equation:

[0143]

[0144] The foam suppression performance test results: the total foam volume of the purified sample (0.1g) is 72mL, and the foam suppression value P is 0.14; the total foam volume of the purified sample (0.05g) is 81mL, and the foam suppression value P is 0.04. Its foam suppression performance is not good.

[0145] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A low foaming surfactant, characterized in that Has the following structure: or Where n = 12, 14, 16, 18, C n H 2n+1 It has a straight chain or branched chain structure.

2. The method for preparing the low-foaming surfactant according to claim 1, characterized in that: include: Synthesize intermediate M1 and intermediate M2, and then mix intermediate M1 and intermediate M2 to react, so as to obtain a low-foaming surfactant; The general structural formula of the intermediate M1 is C n H 2n+1 NHCH2CH2CH2NHCH2CH2CH2SO3H, Where n = 12, 14, 16, 18, C n H 2n+1 It is a straight chain or branched chain structure; The structural formula of the intermediate M2 is 3. The method for preparing the low-foaming surfactant according to claim 2, characterized in that: The preparation method of the intermediate M1 comprises: dissolving alkyl-1,3-propylene diamine and 1,3-propane sultone in a solvent, and reacting to obtain the intermediate M1.

4. The method for preparing the low-foaming surfactant according to claim 2, characterized in that: The preparation method of the intermediate M2 comprises: mixing a trimethylamine aqueous solution, hydrochloric acid and epichlorohydrin, and reacting them to obtain the intermediate M2.

5. The method for preparing the low-foaming surfactant according to claim 2, characterized in that: The preparation method comprises: 1) mixing alkyl-1,3-propylene diamine, an alcohol solvent and 1,3-propane sultone to react to obtain an intermediate M1; 2) mixing trimethylamine aqueous solution, hydrochloric acid and epichlorohydrin, and reacting to obtain intermediate M2; 3) The intermediate M2 is added dropwise to the intermediate M1, and the mixture is mixed and reacted to obtain a low-foaming surfactant.

6. The method for preparing a low-foaming surfactant according to claim 5, characterized in that: In step 1), in the synthesis of intermediate M1, the reaction temperature of the mixed reaction is 60-80° C., and the reaction time is 3-5 h.

7. The method for preparing a low-foaming surfactant according to claim 5, characterized in that: In step 2), in the synthesis of intermediate M2, the reaction temperature of the mixed reaction is 42°C and the reaction time is 3h; Or, in step 3), the reaction temperature of the mixed reaction is 60-80° C., and the reaction time is 2-4 h.

8. The method for preparing a low-foaming surfactant according to claim 5, characterized in that: The molar ratio of the alkyl-1,3-propylene diamine, alcohol solvent, 1,3-propane sultone, trimethylamine, hydrochloric acid and epichlorohydrin is 1 mol: 14.00-26.00 mol: 1.00-1.20 mol: 1.00-2.30 mol: 1.00-2.30 mol: 1.00-2.30 mol.

9. The method for preparing a low-foaming surfactant according to claim 5, characterized in that: In step 1), the alcohol solvent is ethanol or isopropanol with a low carbon number; Alternatively, the alkyl-1,3-propylene diamine is at least one selected from dodecyl-1,3-propylene diamine, tetradecyl-1,3-propylene diamine, hexadecyl-1,3-propylene diamine, and octadecyl-1,3-propylene diamine.

10. The method for preparing a low-foaming surfactant according to claim 9, characterized in that: The alkyl-1,3-propylene diamine is N-hydrogenated tallow-1,3-propylene diamine.

11. The method for preparing a low-foaming surfactant according to claim 5, characterized in that: The specific steps include: (1) dissolving alkyl-1,3-propylene diamine in an alcohol solvent, heating and stirring to dissolve, then adding 1,3-propane sultone, and after the addition is complete, stirring and reacting at 60-80° C. for 3-5 hours to obtain intermediate M1; (2) Take an appropriate amount of trimethylamine aqueous solution, add hydrochloric acid in batches, and then add epichlorohydrin after the addition of hydrochloric acid is completed. After the addition of epichlorohydrin is completed, stir and react at 42° C. for 3 hours to obtain intermediate M2; (3) Add intermediate M2 to intermediate M1 and react at 60-80° C. for 2-4 h to obtain a low-foaming surfactant.

12. The method for preparing the low-foaming surfactant of claim 2, characterized in that: The method also includes: a separation and purification process.

13. The method for preparing the low-foaming surfactant of claim 12, characterized in that: The solvent of the synthetic product of step 1) or step 3) is evaporated, and then recrystallized and separated and purified using an organic solvent.

14. The method for preparing the low-foaming surfactant of claim 13, characterized in that: The organic solvent is methanol.

15. Use of the low-foaming surfactant according to claim 1 as a low-foaming surfactant or emulsifier.

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