CN109999716A - A kind of non-ionic fluorosurfactant and its preparation method and application - Google Patents

Abstract

The invention provides a nonionic fluorine-containing compound, a preparation method and application thereof, and belongs to the field of new fluorine-containing materials. A non-ionic fluorosurfactant whose structure is shown in the general formula (I): The active agent does not contain PFOA-like substances, and is an environmentally friendly and inexpensive non-ionic wetting agent for fluorine-containing substrates. And can be used as a substrate wetting agent in underwater coatings, and the wetting effect is good. The invention discloses a method for preparing a nonionic fluorine-containing surfactant, which is simple and environmentally friendly, and can realize continuous production.

Description

A kind of nonionic fluorine-containing surfactant and its preparation method and application

technical field

The invention relates to a nonionic fluorine-containing compound, a preparation method and application thereof, and belongs to the field of new fluorine-containing materials.

Background technique

Wettability refers to the tendency of a fluid to spread or adsorb on a solid surface in the presence of immiscible phase fluids. When applied, the coating should be able to fully wet the substrate in order to obtain a smooth, defect-free surface. In solvent-based coatings, due to the low surface tension of the solvent, there is basically no problem of wetting of the substrate. With the increasing global attention to environmental issues, water-based coatings have been widely used. The surface tension of water is 72.75×10 ^-3 N·m ^-1 , which is larger than that of common substrates, which brings about the problem of difficult wetting.

Substrate wetting agents for waterborne coatings based on heptamethyltrisiloxane polyether are well known, which can significantly reduce the surface tension of water to 21 mN/m, have good wetting, strong adhesion, It has the advantages of excellent spreadability, high pore permeability and good rain erosion resistance. However, this type of wetting agent is easily hydrolyzed under acidic or alkaline conditions, which limits its application under certain conditions; in some systems, the surface tension needs to be reduced to 20 mN/m, so that ordinary silicone systems are very Difficult to meet requirements.

All or part of the hydrogen atoms in the hydrocarbon chain of the hydrocarbon surfactant are replaced by fluorine atoms, and it becomes a fluorocarbon surfactant. Since fluorine is the most electronegative element, the bond energy of the carbon-fluorine bond is high. In addition, the atomic radius of the fluorine atom is larger than that of the hydrogen atom, which can effectively protect the perfluorinated C-C bond, so it has unique properties such as high stability and low surface tension, which can even reduce the surface tension down to 17-18mN/m, which is very good as a substrate wetting agent in underwater coatings. Existing ones such as 3M fluorocarbon surfactant FC-4430, DuPont's FS-63 anionic fluorine-containing wetting agent, etc., but these prices are quite expensive, reaching more than 1,000 yuan/kg.

Among the existing patents, nonionic fluorosurfactants have also received more attention. For example, the Chinese Patent Application No. 201080039806.1 discloses the use of a reactant of a fluorine-containing C6 epoxide and a two-terminal hydroxyl type polyethylene glycol to prepare a non-ionic fluorine-containing surfactant, which is used as a defogger; the application No. 201210344043.2 discloses It is the amidation reaction of perfluoroalkylsulfonyl fluoride and N,N'-dimethyl(ethyl)-1,3-propanediamine to obtain intermediate 1, which is purified and mixed with acetone as solvent. Reaction of ethylene oxide or chloroethanol to give intermediate 2(N'-3-(dimethyl(ethyl))-propyl-(N-perfluorobutylsulfonyl-N-epoxy)-amine ), intermediate 2, and then carry out ring-opening reaction with ethylene oxide in different proportions to obtain non-ionic fluorosurfactant; the invention patent with application number 201710034468.6 discloses perfluoroalkyl iodide and vinyl or allyl A method for preparing nonionic surfactant by reaction of base polyoxyethylene ether.

In these existing patents, the fluorine-containing raw materials are expensive and the preparation method is complicated, and the development of a cheap, easy-to-synthesize nonionic surfactant is urgently needed in the market. Octafluoroisobutene is a colorless, slightly grassy, toxic gas. During the production of tetrafluoroethylene and hexafluoropropylene by pyrolysis, there will be perfluoroisobutene by-products, which are very difficult to handle. The early treatment method is to bury the residual liquid containing perfluoroisobutene or put it into steel cylinders and sink it into the open sea, but it cannot solve the fundamental problem. The most thorough and simple method is direct incineration, but if the perfluoroisobutene leaks, it is very dangerous. At present, it is more commonly used in industry to absorb perfluoroisobutene with lower alcohols (usually methanol) and add them to moderately toxic fluoroethers. For fluoroether, the common treatment method is incineration to generate carbon dioxide and hydrogen fluoride, and then absorb it with lime water to generate calcium fluoride, and the treated flue gas is discharged at high altitude. From the perspective of full utilization of resources, this is undoubtedly a huge waste, and the waste gas and residue generated after treatment will also pollute the environment. Therefore, how to comprehensively utilize fluoroisobutene is a common problem in the fluorine chemical industry.

The development of non-ionic fluorine-containing surfactants with octafluoroisobutylene as the fluorocarbon source can not only solve the bottleneck restricting the production of hexafluorobutene, but also provide a low-cost fluorine-containing substrate wetting agent for water-based coatings. Fluorosurfactants using octafluoroisobutene as a fluorocarbon source are environmentally friendly and do not have the persistent toxicity problem of C8 fluorosurfactants. Therefore, this method not only has extremely high technical and economic value, but also has Conducive to the development of my country's material industry.

SUMMARY OF THE INVENTION

The first object of the present invention is to provide a non-ionic fluorine-containing surfactant, which does not contain PFOA-like substances, and is an environmentally friendly and inexpensive non-ionic fluorine-containing substrate wetting agent, and the wetting agent Works well.

The second object of the present invention is to provide a method for preparing a non-ionic fluorine-containing surfactant, which is easy to prepare, environmentally friendly, and can realize continuous production.

The third object of the present invention is to provide a non-ionic fluorosurfactant used as a substrate wetting agent in underwater coatings.

The present invention solves its technical problem by adopting the following technical solutions to realize:

A non-ionic fluorosurfactant whose structure is shown in the general formula (I):

R ¹ is a group of formula (C _m H _2m O-) _s R ³ , wherein m is a number greater than or equal to 2.0 and not greater than 2.5, s is a number between 6 and 30, and R ³ is a number between 1 and 30. Alkyl or acetyl group of 4 carbon atoms, R ¹ can be represented as (C ₃ H ₆ O) _P (C ₂ H ₄ O) _q R ³ , wherein ethylene oxide and propylene oxide can be random copolymerization or block A copolymer wherein P is a number from 0 to 10, q is a number from 6 to 20, and at least 60 mole percent of the oxyalkylene groups are oxyethylene groups.

A preparation method of a non-ionic fluorine-containing surfactant, comprising: obtaining a polyether having a primary hydroxyl group and octafluoroisobutene through an addition reaction, and the chemical structural formula of the octafluoroisobutene is represented by (II):

The molar ratio of primary hydroxypolyether and octafluoroisobutylene is 1.1:1-1.05:1.

A non-ionic fluorine-containing surfactant is used as a wetting agent in water-based paints and inks.

The beneficial effects of a nonionic fluorine-containing compound and its preparation method and application provided by the present invention are:

A non-ionic fluorine-containing surfactant, free of PFOA-like substances, is an environment-friendly and inexpensive non-ionic fluorine-containing substrate wetting agent. And can be used as a substrate wetting agent in underwater coatings, and the wetting effect is good.

The invention discloses a method for preparing a nonionic fluorine-containing surfactant, which is simple and environmentally friendly, and can realize continuous production.

Detailed ways

In order to make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below. The ¹ H NMR spectrum was measured with a Bruker 400MHz nuclear magnetic resonance apparatus, deuterated chloroform was used as the solvent, and tetramethylsilane (TMS) was used as the internal standard. If the specific conditions are not indicated in the examples, it is carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used without the manufacturer's indication are conventional products that can be purchased from the market.

A non-ionic fluorosurfactant and its preparation method and application according to the embodiments of the present invention will be specifically described below.

A non-ionic fluorosurfactant whose structure is shown in the general formula (I):

R ¹ is a group of formula (C _m H _2m O-) _s R ³ , wherein m is a number greater than or equal to 2.0 and not greater than 2.5, s is a number between 6 and 30, and R ³ is a number between 1 and 30. Alkyl or acetyl group of 4 carbon atoms, R ¹ can be represented as (C ₃ H ₆ O) _P (C ₂ H ₄ O) _q R ³ , wherein ethylene oxide and propylene oxide can be random copolymerization or block A copolymer wherein P is a number from 0 to 10, q is a number from 6 to 20, and at least 60 mole percent of the oxyalkylene groups are oxyethylene groups.

Further, in the non-ionic fluorosurfactant, the R ³ is methyl. As a hydrophilic end, the hydrophilicity of methoxy is better than that of ethoxy, butoxy and other longer alkyl chains.

Further, in the non-ionic fluorosurfactant, the P is 1 to 3, and polypropylene oxide is hydrophobic, and if P is too large, its solubility in water will be affected.

In the nonionic fluorosurfactant, the q is a numerical value of 8 to 18. Polyethylene oxide is to increase the water solubility of fluorine-containing surfactants. If q is too small, the water solubility is too poor, and if q is too large, the fluorine content will be low, and the ability to reduce the surface tension of the system will be reduced.

In the nonionic fluorosurfactant, at least 80 mol% of the oxyalkylene groups are oxyethylene groups, so that the prepared fluorosurfactant has good surface activity.

The present invention also provides a preparation method of the non-ionic fluorosurfactant, which comprises: making the polyether and octafluoroisobutylene with primary hydroxyl groups at a certain temperature under weakly acidic or neutral, solvent or solvent-free conditions obtained by an addition reaction. The chemical structural formula of octafluoroisobutene is represented by (II):

Primary hydroxyl polyether preparation methods are known, including some commercial products, such as MPEG350 (methoxy-terminated, molecular weight of 350), MPEG400 (methoxy-terminated, molecular weight of 400), MPEG600 (methoxy-terminated, molecular weight of 400) group-terminated, molecular weight is 600), MPEG750 (methoxy-terminated, molecular weight is 750), etc.

Octafluoroisobutene contains two trifluoromethyl groups on one carbon of the olefinic bond, and the trifluoromethyl group has a strong electron-withdrawing effect, which leads to the electrophilic addition and substitution of octafluoroisobutene and hydroxyl, amino, sulfhydryl and other groups. reaction.

The common fluorocarbon source of fluorosurfactant is fluoroalkyl iodide, or fluoroalcohol, fluoroether, perfluorosulfonyl fluoride, etc., which are expensive and complicated in preparation process, which ultimately leads to high price of fluorosurfactant, which restricts its large-scale application. Since this example uses pure octafluoroisobutene and does not contain PFOA-like substances, it is an environmentally friendly and inexpensive non-ionic wetting agent for fluorine-containing substrates. The treatment method of the refractory by-product octafluoroisobutene turns waste into treasure and promotes the healthy development of the fluorine chemical industry.

Further, it is obtained by addition of primary hydroxyl polyether and octafluoroisobutylene under weak acid conditions, and the acid catalyst used is acetic acid, p-toluenesulfonic acid, trifluoroacetic acid, and sulfamic acid. Some literature (Zeifman Y V, Ter-Gabrielyan EG, Gabaryan NP, et al. The chemistry of perfluoroisobutene[J]. Russian Chemical Reviews, 1984, 53(3): 256-273.) pointed out that the reaction between octafluoroisobutene and primary hydroxyl groups When , it is an addition reaction under neutral or weakly acidic conditions, and a substitution reaction under basic conditions. In order to obtain the nonionic fluorosurfactant by addition, it is selected to obtain the nonionic fluorine-containing surfactant under the condition of weak acidity in this example. Acetic acid, p-toluenesulfonic acid, trifluoroacetic acid, sulfamic acid can be added to the system to adjust the acidity of the system; other organic acids, such as methanesulfonic acid, propionic acid, butyric acid, benzoic acid, phthalic acid is also possible. In terms of conversion efficiency, acetic acid, p-toluenesulfonic acid, trifluoroacetic acid, and sulfamic acid have higher catalytic efficiency.

In this embodiment, the molar ratio of the primary hydroxyl polyether and octafluoroisobutylene is 2:1-1.05:1. Compared with octafluoroisobutylene, the polyether of primary hydroxyl group is safe, therefore, the primary hydroxyl acrylate monomer can be excessive, so that the reaction of octafluoroisobutylene can be completed.

Preferably, the molar ratio of the primary hydroxyl polyether and octafluoroisobutylene is 1.1:1-1.05:1. For economy, a slight excess of primary hydroxyl polyethers can be controlled.

Preferably, the addition temperature of the primary hydroxyl polyether and octafluoroisobutylene is 20°C to 80°C. When the reaction temperature is lower than 20 °C, such as 10 °C, the reaction can also be carried out, but the reaction rate is too slow; when the reaction temperature is higher than 80 °C, side reactions increase, such as substitution reactions, which will eventually lead to low yields of target products.

In this embodiment, the addition reaction of the primary hydroxyl polyether and octafluoroisobutylene can be prepared by a bulk method, or can be carried out in the presence of a solvent. If it is a solvent, the selected solvent is a solvent that does not react with the two monomers, such as ketones, esters, aromatic hydrocarbons, ethers and other solvents. Can be acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ethyl acetate, butyl acetate, amyl acetate, octyl acetate, toluene, xylene, mesitylene, diethyl ether, propylene glycol methyl ether acetate, etc. solvent. The addition reaction is preferably carried out under solvent-free conditions.

The above-mentioned non-ionic fluorosurfactant can be used as a wetting agent in water-based paints and inks.

The features and performances of the present invention will be further described in detail below in conjunction with the embodiments.

Example 1

In the pressure reactor, nitrogen was evacuated for 3 times, and then 70g (0.2mol) MPEG350, 0.01g p-toluenesulfonic acid, 38g (0.19mol) octafluoroisobutyl ester were added, and the reaction was carried out at 60°C for 12h. Octafluoroisobutene After the reaction was completed, a trace amount of fluoroisobutene was removed by passing nitrogen, and it was absorbed with methanol to obtain 106 g of colorless and transparent liquid, and the conversion rate was 98.1%. The chemical structure of the product was characterized by ¹ H NMR. ¹ H NMR (400 MHz, CDCl ₃ ), δ (TMS, ppm), 3.40 (3H, -CH ₃ ), 3.52 (32H, -CH ₂ -), 3.98 (1 H, =CH-).

Example 2

The pressure reactor was evacuated with nitrogen for 3 times, and then 80g (0.2mol) MPEG400, 0.003g trifluoroacetic acid, 39g (0.195mo) octafluoroisobutene were added, and the reaction was carried out at 50°C for 15h. A trace amount of fluoroisobutene was removed and absorbed with methanol. 111.1 g of colorless and transparent liquid was obtained, and the conversion rate was 93.2%. The chemical structure of the product was characterized by ¹ H NMR. ¹ H NMR (400 MHz, CDCl ₃ ), δ (TMS, ppm), 3.40 (3H, -CH ₃ ), 3.52 (36H, -CH ₂ -), 3.98 (1 H, =CH-).

Example 3

In the pressure reactor, nitrogen was evacuated for 3 times, and then 120g (0.2mol) of MPEG600, 0.01g of p-toluenesulfonic acid, 36g (0.18mol) of octafluoroisobutene were added, and the reaction was carried out at 40°C for 18h, and the reaction of octafluoroisobutene was complete. , remove a small amount of octafluoroisobutene through nitrogen, and absorb it with methanol. 150.1 g of colorless and transparent liquid was obtained, and the conversion rate was 96.1%. The chemical structure of the product was characterized by ¹ H NMR. ¹ H NMR (400 MHz, CDCl ₃ ), δ (TMS, ppm), 3.40 (3H, -CH ₃ ), 3.52 (56H, -CH ₂ -), 3.98 (1 H, =CH-).

Example 4

The pressure reactor was evacuated and replaced by nitrogen for 3 times, and then 150g (0.2mol) of MPEG750, 0.01g of p-toluenesulfonic acid, 39g (0.195mol) of octafluoroisobutene were added, and the reaction was carried out at 60°C for 18h, and the reaction of octafluoroisobutene was complete. , remove a small amount of octafluoroisobutene through nitrogen, and absorb it with methanol. 180.1 g of colorless and transparent liquid was obtained, and the conversion rate was 95.1%. The chemical structure of the product was characterized by ¹ H NMR. ¹ H NMR (400 MHz, CDCl ₃ ), δ (TMS, ppm), 3.40 (3H, -CH ₃ ), 3.52 (68H, -CH ₂ -), 3.98 (1 H, =CH-).

Experimental example

The nonionic fluorosurfactant aqueous wetting agent provided in Examples 1-4 was used for detection by spreading measurement.

The nonionic fluorosurfactant (0.1 g) was dissolved in 100 ml of distilled water and the solution (0.05 ml) was placed on a PVC plate by means of a micropipette. Due to the low surface tension of fluorosurfactants, water droplets will spread spontaneously, and the diameter (in mm) of the wetted area occupied by the spreading of the aqueous solution is a direct measurement of non-ionic fluorosurfactants. The results are shown in the table. 1.

Table 1 Spreading situation of wetting agent on PVC board

It can be seen from the above test results that the nonionic fluorosurfactant has better wetting effect than commercial surfactants.

The above-described embodiments are some, but not all, embodiments of the present invention. The detailed descriptions of the embodiments of the invention are not intended to limit the scope of the invention as claimed, but are merely representative of selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Claims (10)

1. a non-ionic fluorine-containing surfactant, is characterized in that, its structure is as shown in general formula (I): R ¹ is a group of formula (C _m H _2m O-) _s R ³ , wherein m is a number greater than or equal to 2.0 and not greater than 2.5, s is a number between 6 and 30, and R ³ is a number between 1 and 30. Alkyl or acetyl group of 4 carbon atoms, R ¹ can be represented as (C ₃ H ₆ O) _P (C ₂ H ₄ O) _q R ³ , wherein ethylene oxide and propylene oxide can be random copolymerization or block A copolymer wherein P is a number from 0 to 10, q is a number from 6 to 20, and at least 60 mole percent of the oxyalkylene groups are oxyethylene groups. 2 . The nonionic fluorosurfactant according to claim 1 , wherein the R ³ is a methyl group. 3 . 3 . The nonionic fluorosurfactant according to claim 1 , wherein the P is 1 to 3. 4 . 4 . The nonionic fluorosurfactant according to claim 1 , wherein the q is a value ranging from 8 to 18. 5 . 5 . The nonionic fluorosurfactant according to claim 1 , wherein at least 80 mol % of the oxyalkylene groups are oxyethylene groups. 6 . 6. A method for preparing a nonionic fluorosurfactant according to any one of claims 1 to 5, characterized in that it comprises: passing a polyether having a primary hydroxyl group and octafluoroisobutylene through an addition reaction Obtained, the chemical structural formula of the octafluoroisobutene is represented by (II): The molar ratio of the polyether with primary hydroxyl group and the octafluoroisobutene is 1.1:1-1.05:1. 7 . The method for preparing a nonionic fluorosurfactant according to claim 6 , wherein the polyether having a primary hydroxyl group and the octafluoroisobutylene undergo an addition reaction under weakly acidic conditions. 8 . 8. the preparation method of nonionic fluorine-containing surfactant according to claim 7, is characterized in that, under weak acid condition, the acid catalyst used is acetic acid, p-toluenesulfonic acid, trifluoroacetic acid and amino acid any of the sulfonic acids. 9 . The method for preparing a nonionic fluorosurfactant according to claim 6 , wherein the addition temperature of the primary hydroxyl polyether and the octafluoroisobutylene is 20° C. to 80° C. 10 . 10. The nonionic fluorosurfactant according to any one of claims 1-5 is used as a wetting agent in water-based paints and inks.