CN106279706A - A kind of preparation method of polyether grafting chitosan derivatives crude oil desalting demulsifier - Google Patents

Abstract

The invention relates to a preparation method of a polyether grafted chitosan derivative crude oil desalting demulsifier. The specific steps are as follows: (1) carry out aldehyde modification of polyethylene glycol monomethyl ether; (2) prepare glycidyl dimethyl alkyl ammonium chloride; (3) prepare quaternized carboxyalkyl chitosan sugar; (4) reacting aldehydized modified polyethylene glycol monomethyl ether with quaternized carboxyalkyl chitosan to obtain polyether grafted chitosan derivative crude oil desalination demulsifier. The invention uses chitosan natural macromolecular compounds as raw materials, and has many advantages such as wide source, natural, non-toxic, sustainable, good biocompatibility and degradability of products. The prepared demulsifier not only has a good demulsification and dehydration effect, but also has a negative charge on the negatively charged ions such as metal cations and naphthenate groups and the surface due to the large number of carboxyalkyl groups and quaternary ammonium salt groups on the demulsifier molecules. The particles have a strong binding ability, so it has the ability to remove oil-soluble salts while breaking the emulsion.

Description

A kind of preparation method of polyether grafted chitosan derivative crude oil desalination demulsifier

technical field

The invention relates to a preparation method of a polyether grafted chitosan derivative crude oil desalination demulsifier, belonging to the field of petrochemical industry.

Background technique

With the rapid development of industry, the demand for oil is increasing, and it is of great significance to enhance oil recovery. As the use of chemical flooding continues to increase, coupled with the increasingly heavy and high acid value of crude oil, the content of metal ions in crude oil is gradually increasing. The salts in crude oil are mainly inorganic salts, most of which are soluble in the water contained in them, and water and oil form a stable water-in-oil (W/O) emulsion. The key to desalting crude oil is dehydration, and the key to dehydration is demulsification. The natural emulsion in crude oil is adsorbed at the oil-water interface to form a viscoelastic film with a certain strength, which creates a dynamic obstacle for the coalescence of emulsion droplets and makes the crude oil emulsion stable. The principle of demulsification is the factor that destroys the stability of the emulsion. There are many researches on demulsification of crude oil at home and abroad, and many demulsification methods have been successfully developed. The most commonly used in oil field is to add demulsifier, demulsifier is one of the essential chemical reagents in today's oil field and refinery. With the development of the petroleum industry, the demand for demulsifiers is increasing, and the performance requirements are more stringent. If a new type of high-efficiency deep desalination demulsifier is developed, which can remove oil-soluble salts while breaking the demulsification, it will be of great significance to my country's crude oil processing.

Crude oil demulsification methods mainly include chemical method, electrical method, centrifugal separation method, ultrasonic method, biological method and so on. Among them, the chemical method and the electrical method are the most commonly used, but the electrical method has higher requirements on equipment and process conditions, the implementation is more complicated, and the initial investment and later operation costs are relatively high; the chemical method is an economical and reasonable method.

The demulsification process of the demulsifier is generally divided into three stages: (1) After the demulsifier is added to the crude oil emulsion, it is dispersed in the entire oil phase and can enter the emulsified water droplets; (2) The demulsifier penetrates into the Emulsify the protective layer of water droplets, and make the protective layer fragile, wrinkled and damaged. After the protective layer is destroyed, the emulsified water droplets approach and contact each other; (3) the water droplets coalesce, and the emulsified water droplets are separated from the continuous direction.

Since Barnickel reported in 1914 to use 0.1% FeSO ₄ solution to demulsify the emulsified crude oil at 35°C to 60°C, three generations of demulsifiers have been developed successively. From the 1920s to the 1930s, in order to solve the demulsification of oil-in-water crude oil emulsions, the first generation of low-molecular-weight ionic demulsifiers appeared, such as fatty acid salts, naphthenates and other anionic demulsifiers, quaternary ammonium salts, etc. Cationic demulsifier. The advantage of this type of demulsifier is low price, and the disadvantages are large dosage, poor effect, and easy to be affected by electrolytes. The industrialization of ethylene oxide production in the 1940s and 1950s led to the emergence of ethylene oxide and propylene oxide block copolymers. Thus, the second generation of demulsifiers for water-in-oil emulsified crude oil has been developed, mainly low-molecular non-ionic surfactants. Since the 1960s, people have developed the third generation of demulsifiers based on high molecular weight polyether. A lot of research has been done on crude oil demulsifier abroad, and a lot of patents have been proposed. The earliest nonionic surfactants used as demulsifiers were prepared by grafting and copolymerizing a certain amount of ethylene oxide with alkylphenols and fatty alcohols as hydrophobic groups. With the large-scale field experiments of tertiary oil recovery technology, new crude oil demulsifiers are constantly emerging. After entering the 1980s, pure ethylene oxide propylene oxide block polyether demulsifiers began to be replaced by polyamines, polymers, and zwitterionic demulsifiers, and the minimum dosage dropped below 100mg/L. However, the disadvantages of these demulsifiers are strong specificity and poor adaptability. Therefore, people have developed composite demulsifiers and ultra-high molecular weight high-efficiency demulsifiers through modification or compounding, thus pushing the application research of demulsifiers to a new level.

In order to solve the above problems, a method for preparing crude oil demulsifiers with multiple initiators has emerged in recent years. Chinese patent CN200510130345 introduces a polyether type crude oil demulsifier. Polyethylene polyamine or nonylphenolic resin is used as the initiator to react with ethylene oxide and propylene oxide to obtain polyether, and then the polyether is mixed with chain extender and pyridine to obtain it. The invention has the advantages of simple preparation process, less dosage, good demulsification and dehydration effect, low cost, etc., but the demulsifier cannot achieve the effect of low temperature demulsification to save heat energy. Chinese patent CN 201410710742 introduces a low-temperature crude oil demulsifier. It is obtained by copolymerizing glycidyl methacrylate and hexafluorobutyl methacrylate with acetone and acrylic acid as initiators. The disadvantages of high temperature required for demulsification, long demulsification time and poor dehydration water quality of existing products are avoided. It can break emulsion at low temperature, reduce gas consumption per ton of oil, save energy, improve economic benefits and equipment processing efficiency. However, this demulsifier has strong specificity and poor stability, and cannot be suitable for demulsification of many different types of crude oil. Chinese patent CN 201310289037.6 introduces a polysaccharide modified crude oil demulsifier. The polysaccharide is used as the starting agent, and it is modified by quaternization and polyether grafting. The demulsifier has many advantages such as wide source, natural, non-toxic, sustainable, and good use safety. The demulsifier not only has a good effect of demulsification and dehydration, but also a large number of hydroxyl groups and other groups contained in the demulsifier molecule have a certain ability to chelate metal ions, but the binding ability is not strong, and it cannot remove different types and a large number of metal cations during dehydration. , still need to be improved. Therefore, it is necessary to develop a low-temperature demulsification, rapid demulsification, expand the application range of the demulsifier to crude oil, and have a good dehydration and desalination effect.

Chitin has a wide range of sources, and its content is second only to cellulose, which is the second largest type of organic compound in the world. Chitosan is the product of deacetylation of chitin. Compared with xanthan gum and guar gum, the molecular chain contains more reactive amino groups and is easier to graft and modify. Chitosan natural polymer has excellent biocompatibility and environmental friendliness, large molecular weight, many active hydrogen, branched structure and unique rheological properties. Its derivatives have strong flocculation ability, occupy a large area at the oil-water interface, have good temperature resistance and high interfacial activity, and are excellent candidates for demulsifier initiators. The introduction of carboxyalkyl groups and quaternary ammonium salt groups into the molecular chain of chitosan has a strong binding ability to negatively charged ions such as metal cations and naphthenate groups in crude oil. At the same time, by controlling the position and degree of substitution of each substituent, as well as the length of the polyether side chain, carboxyalkyl group and quaternary ammonium salt group, a series of high-efficiency demulsifiers suitable for crude oil with different properties can be obtained, and Oil-soluble salts can be removed while breaking the emulsification.

Contents of the invention

The purpose of the present invention is to propose a kind of preparation method of polyether grafted chitosan derivative crude oil desalination demulsifier for the problems existing in the above-mentioned prior art, obtain a series of crude oils suitable for different properties, and can be used in demulsification Efficient demulsifier for removing oil-soluble salts at the same time.

To achieve the above object, the technical solution provided by the invention is:

A preparation method of polyether grafted chitosan derivative crude oil desalination demulsifier, is characterized in that, comprises the following steps:

1) carrying out hydroformylation of polyethylene glycol monomethyl ether terminal hydroxyl groups to obtain hydroformylated modified polyethylene glycol monomethyl ether;

2) Preparation of glycidyl dimethyl alkyl ammonium chloride: Add epichlorohydrin dropwise to N,N-dimethyl alkyl amine, raise the temperature to 25°C-40°C, and react at constant temperature for 6-30h. The reaction product is separated and purified to obtain glycidyl dimethyl alkyl ammonium chloride; wherein the carbon chain length of the alkyl group in the N,N-dimethyl alkylamine is C ₆ -C ₃₄ ;

3) Preparation of quaternized carboxyalkyl chitosan: dissolving carboxyalkyl chitosan in solvent A, adjusting the pH value of the solution with lye, and then dissolving the glycidyl dimethyl alkyl chloride obtained in step 2) Dissolve ammonium chloride in solvent A, add dropwise to the reaction system, heat up to 60-80°C, react for 8-24 hours, dialyze the reaction solution, and freeze-dry to obtain the solid product quaternized carboxyalkyl chitosan;

4) Reaction of modified polyethylene glycol monomethyl ether with quaternized carboxyalkyl chitosan: dissolve the quaternized carboxyalkyl chitosan prepared in step 3) in solvent B, and then dissolve the quaternized carboxyalkyl chitosan prepared in step 1) The obtained hydroformylated modified polyethylene glycol monomethyl ether is dissolved in solvent B and added dropwise to the reaction system, adding an appropriate amount of lye to adjust the pH value of the solution within a certain range, then adding a certain amount of reducing agent, and raising the temperature to 50~ 80° C., constant temperature reaction for 6-12 hours, the reaction liquid is separated and purified, and freeze-dried to obtain the final product of quaternized carboxyalkyl chitosan grafted with polyethylene glycol monomethyl ether.

According to the above scheme, preferably, the specific steps of the formylation modification described in step 1) are: dissolving 1 mole part of polyethylene glycol monomethyl ether in a certain amount of solvent C, and keeping the reaction in an inert gas environment , add 5-20 parts of formylation reagent under the condition of constant stirring at room temperature, raise the temperature to 15-35°C, react at constant temperature for 5-15 hours, separate and purify the reaction solution, and dry it in vacuum to obtain formylated polyethylene glycol monomethyl ether; , the number average molecular weight of the polyethylene glycol monomethyl ether is 350, 500, 750, 1000, 1900 or 5000. Preferably, the solvent C is one or more of dichloromethane, chloroform, dimethyl sulfoxide, and ether. Preferably, the formylation reagent is acetic anhydride. Preferably, the inert gas environment is nitrogen or argon. Preferably, the separation and purification is to add the reaction solution into anhydrous ether, dissolve the obtained precipitate with chloroform and then recrystallize with ether solution, and repeat this step once.

According to the above scheme, preferably, in step 2), the ratio of N,N-dimethylalkylamine to epichlorohydrin in parts by mass is 1.93-2.97:3.7.

According to the above scheme, preferably, in step 2), the separation and purification is rinsing with acetone and then vacuum drying.

According to the foregoing scheme, preferably, the preparation method of the carboxyalkyl chitosan described in step 3) is:

In parts by weight, 1.61 parts of chitosan were swelled, and the suspension was adjusted to be alkaline with lye, stirred overnight at -15°C to -25°C, and 7.4 to 14.8 parts of carboxylation reagent sodium chloroalkylate were added, The temperature is raised to 30-60° C., stirred and reacted for 3-12 hours, the reaction product is separated and purified, and freeze-dried to obtain carboxyalkyl chitosan; wherein, the carbon chain length of the sodium chloroalkylate is C ₂ -C ₁₀ . Preferably, the separation and purification specifically include: filtering, rinsing the obtained solid product with 80% ethanol and absolute ethanol respectively, drying at 60° C. for one day, dissolving the solid in water and dialysis.

According to the above scheme, preferably, in step 3), the ratio of carboxyalkyl chitosan to glycidyl dimethyl alkyl ammonium chloride in parts by mass is 3.21:1.93˜7.7.

According to the above scheme, preferably, in step 3), after dissolving the carboxyalkyl chitosan with solvent A and adjusting the pH value of the solution with lye, the temperature of the solution is raised to 45-50° C., and the reaction is performed at constant temperature for 1 hour. The effect of this step is to fully open the carboxyalkyl chitosan chain, and the grafting is more uniform.

According to the above scheme, preferably, in step 3), the pH range is 8-10.

According to the above scheme, preferably, in step 4), the pH range is 5-7.

According to the above scheme, preferably, in step 4), the mass fraction ratio of the quaternized carboxyalkyl chitosan, the formaldehyde modified polyethylene glycol monomethyl ether and the reducing agent is: (0.47～1.05 ): (0.35~5): (0.08~0.183).

According to the above scheme, preferably, in step 4), the reducing agent includes but not limited to sodium borohydride or sodium cyanoborohydride.

According to the above scheme, preferably, the solvent A is distilled water, isopropanol, sodium hydroxide solution, hydrochloric acid solution, N,N dimethylformamide, N,N dimethylacetamide, dimethyl sulfoxide, acetic acid , One or more mixtures in methanol.

According to the above scheme, preferably, the solvent B is distilled water, isopropanol, sodium carbonate aqueous solution, N,N-dimethylformamide, N,N-dimethylacetamide, acetic acid, ethanol, methanol, acetone, One or more of saturated ammonium sulfate solution.

According to the above scheme, preferably, in each step, the lye is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate.

The synthetic route of the present invention is as follows:

1. Polyethylene glycol monomethyl ether modification:

2. Preparation of glycidyl dimethyl alkyl ammonium chloride:

3. Carboxyalkylation modification of chitosan, reaction of quaternized modified product with modified polyethylene glycol monomethyl ether:

In the prior art, traditional polyether demulsifiers usually use ethylene oxide and propylene oxide as the main raw materials, select substances with active hydrogen as initiators, and obtain block polyether demulsifiers through polymerization etherification; As oilfield development enters the later stage, a large number of compound flooding is widely used in the production process. This process intensifies the degree of emulsification of crude oil and increases the difficulty of demulsification. The demulsification performance of block polyether demulsifiers is limited.

Compared with the prior art, the present invention has the following beneficial effects:

1) The present invention uses chitosan natural polymer compound as raw material, which has many advantages such as wide source, natural, non-toxic, biodegradable and compatible, sustainable and safe to use.

2) The modified chitosan demulsifier obtained by modifying polyethylene glycol monomethyl ether, sodium chloroalkylate, and glycidyl dimethyl alkyl ammonium chloride has high molecular weight, multi-branched, comb-like structure, carboxyalkyl and dimethyl alkylammonium chloride in the side chain have very strong binding ability to negatively charged ions such as metal cations and naphthenate radicals and the particles that are negatively charged on the surface, so the poly The quaternized carboxyalkyl chitosan grafted with ethylene glycol monomethyl ether has good dehydration and desalination effects.

3) in the present invention, when preparing carboxyalkyl chitosan, by the method for alkalization at low temperature, hydrogen bond in the chitosan molecule can be opened more easily, and lye is more easily penetrated in the chitosan molecule, and then The carboxyalkyl side chains are more uniformly grafted onto the chitosan main chain, and the resulting carboxyalkyl chitosan has a stable structure and good solubility properties.

4) The preparation method of polyether grafted chitosan derivative crude oil desalination demulsifier in the present invention can be by selecting sodium carboxyalkylate of different carbon chain lengths, N,N-dimethylalkylamine, polyether, Either change the ratio of raw materials used in the reaction, or change the reaction temperature and time of the reaction system to change the molecular structure of the demulsifier, such as molecular weight, degree of substitution, hydrophobic segment length, aggregated structure, etc., and then regulate the desalination and dehydration of the synthesized high-efficiency demulsifier Effect, so as to be applicable to crude oil with different properties (different origin, different salt and water content).

detailed description

In order to better understand the present invention, the content of the present invention will be further illustrated below in conjunction with examples, but the content of the present invention is not limited to the following examples.

Example 1

A kind of preparation of polyether grafted chitosan derivative crude oil desalination demulsifier, concrete steps are as follows:

(1) Formylation modification of polyethylene glycol monomethyl ether terminal hydroxyl group: take 1.75g (5mmol) polyethylene glycol monomethyl ether (Mn=350) and dissolve it in 30mL of anhydrous dimethyl sulfoxide and 2mL of chloroform In the mixed solution, keep the reaction under nitrogen atmosphere, add 5.1mL (50mmol) acetic anhydride solution under constant stirring at room temperature, heat to 15°C, and react at constant temperature for 5h. After the reaction was completed, the reaction liquid was added to 400 mL of anhydrous ether, and the obtained precipitate was dissolved in chloroform and then recrystallized with ether solution (repeat this step once), and then vacuum-dried at room temperature for 24 hours to obtain the hydroformylated polyethylene glycol monomethyl ether .

(2) Preparation of glycidyl dimethyl dodecyl ammonium chloride: add 2.13g of dodecyl dimethyl tertiary amine to the three-necked flask equipped with agitator, dropping funnel and condensation reflux device, constantly stir , take 3.7g of epichlorohydrin through the dropping funnel and add it dropwise within 30min, keep the temperature at 25°C, and react at constant temperature for 6h. Stop the reaction, rinse the product with acetone, and dry it in vacuum to obtain glycidyl dimethyl dodecyl ammonium chloride.

(3) Preparation of carboxymethyl chitosan: Add 1.61g chitosan to a 250mL flask, add 10mL isopropanol to swell, add 2.5mL 10mol/L sodium hydroxide solution, continue stirring for 30min, and Stir overnight at 15°C, add 7.4g of sodium chloroacetate, heat the reaction mixture to 60°C after the addition is complete, and continue stirring for 3h. After the reaction was completed, the reaction mixture was filtered to obtain a crude product. The product was washed three times with 80% ethanol and absolute ethanol, and dried in a drying oven at 60° C. for one day. The solid was dissolved in water and dialyzed for 3 days, and freeze-dried to obtain N, O‐carboxymethyl chitosan.

(4) Preparation of quaternized carboxymethyl chitosan: Weigh 3.21g of N,O‐carboxymethyl chitosan in a three-necked flask, add 40mL of distilled water, and adjust pH=8～10 with sodium hydroxide solution, Raise the temperature to 50°C, and react at a constant temperature for 1 hour; dissolve 2.78g of glycidyl dodecyl ammonium chloride in 20mL of water and drop it into the reaction system through a constant pressure funnel, raise the temperature to 80°C, and react for 8 hours. After the reaction is completed, the reaction solution is dialyzed for 3 to 5 days, and freeze-dried to obtain a solid product of quaternized carboxymethyl chitosan.

(5) Reaction of modified polyethylene glycol monomethyl ether and quaternized carboxymethyl chitosan: take 0.47g of quaternized carboxymethyl chitosan and place it in a 250mL three-necked flask, add 30mL water to dissolve, and dissolve 0.4 Dissolve 1 g of formylated polyethylene glycol monomethyl ether (Mn=350) in 10 mL of water, add an appropriate amount of potassium carbonate to adjust the pH of the solution to 6, then add 0.08 g of sodium borohydride, dropwise add within 10 min, stir and heat up to 50°C , constant temperature reaction 6h. Pour the reaction solution into a saturated ammonium sulfate solution to precipitate, filter with suction, wash the filtrate several times with ethanol and acetone, and then dry it in vacuum to obtain the target product—quaternized carboxymethyl grafted with polyethylene glycol monomethyl ether Chitosan, as demulsifier 1.

Example 2

A kind of preparation of polyether grafted chitosan derivative crude oil desalination demulsifier, concrete steps are as follows:

(1) Formylation modification of polyethylene glycol monomethyl ether terminal hydroxyl group: take polyethylene glycol monomethyl ether (Mn=750) 3.75g (5mmol) and dissolve in 30mL of anhydrous dimethyl sulfoxide and 2mL of chloroform In the mixed solution, keep the reaction under nitrogen atmosphere, add 5.1mL (50mmol) acetic anhydride solution under constant stirring at room temperature, heat to 20°C, and react at constant temperature for 7h. After the reaction was completed, the reaction liquid was added to 400 mL of anhydrous ether, and the obtained precipitate was dissolved in chloroform and then recrystallized with ether solution (repeat this step once), and then vacuum-dried at room temperature for 24 hours to obtain the hydroformylated polyethylene glycol monomethyl ether .

(2) Preparation of glycidyl dimethyltetradecyl ammonium chloride: add 2.41g tetradecyl dimethyl tertiary ammonium to a three-necked flask equipped with a stirrer, dropping funnel and condensing reflux device, constantly stir , take 3.7g of epichlorohydrin through the dropping funnel and add it dropwise within 30min, keep the temperature at 30°C, and react at constant temperature for 20h. The reaction was stopped, and the product was rinsed with acetone and dried in vacuo to obtain glycidyl dimethyltetradecyl ammonium chloride.

(3) Preparation of carboxyethyl chitosan: Add 1.61g chitosan to a 250mL flask, add 10mL isopropanol to swell, add 2.5mL 10mol/L sodium hydroxide solution, continue stirring for 30min, and Stir overnight at 20°C, add 8.2g of sodium chloropropionate, heat the reaction mixture to 60°C after the addition is complete, and continue stirring for 4 hours. After the reaction is completed, filter the reaction mixture to obtain a solid product. The product is washed three times with 80% ethanol and absolute ethanol respectively, put into a drying oven at 60°C for drying, then dissolve the solid in water, dialyze for 5 days, and freeze-dry to obtain a solid product. N,O-carboxyethyl chitosan.

(4) Preparation of quaternized carboxyethyl chitosan: Weigh 3.21g of N,O-carboxyethyl chitosan in a three-neck flask, add 40mL of distilled water, adjust pH=8～10 with sodium hydroxide solution, The temperature was raised to 45°C, and the reaction was performed at a constant temperature for 1h. Dissolve 2.78g of glycidyltetradecylammonium chloride in 20mL of water and add dropwise to the reaction system through a constant pressure funnel, raise the temperature to 70°C, and react for 16h. After the reaction was completed, the reaction solution was dialyzed for 5 days, and freeze-dried to obtain a solid product, quaternized carboxyethyl chitosan.

(5) Reaction of modified polyethylene glycol monomethyl ether with quaternized carboxyethyl chitosan: take 0.53g of quaternized carboxyethyl chitosan and place it in a 250mL three-necked flask, add 30mL water to dissolve, and dissolve 0.8 Dissolve 1 g of formylated polyethylene glycol monomethyl ether (Mn=750) in 10 mL of water, add an appropriate amount of potassium carbonate to adjust the pH of the solution to 6, then add 0.16 g of sodium borohydride, dropwise add within 10 min, stir and heat up to 65°C , constant temperature reaction 7h. Pour the reaction solution into a saturated ammonium sulfate solution to precipitate, filter with suction, wash the filtrate several times with ethanol and acetone, and then dry it in vacuum to obtain the target product—quaternized carboxyethyl grafted with polyethylene glycol monomethyl ether Chitosan, as demulsifier 2.

Example 3

A kind of preparation of polyether grafted chitosan derivative crude oil desalination demulsifier, concrete steps are as follows:

(1) Formylation modification of polyethylene glycol monomethyl ether terminal hydroxyl group: take polyethylene glycol monomethyl ether (Mn=1000) 5g (5mmol) and dissolve in 30mL of anhydrous dimethyl sulfoxide and 2mL of chloroform In the solution, keep the reaction under nitrogen atmosphere, add 5.1mL (50mmol) acetic anhydride solution under constant stirring at room temperature, raise the temperature to 30°C, and keep the reaction time at constant temperature for 9h. After the reaction was completed, the reaction liquid was added to 400 mL of anhydrous ether, and the obtained precipitate was dissolved in chloroform and then recrystallized with ether solution (repeat this step once), and then vacuum-dried at room temperature for 24 hours to obtain the hydroformylated polyethylene glycol monomethyl ether .

(2) Preparation of glycidyl dimethyl cetyl ammonium chloride: add 2.69g cetyl dimethyl tertiary amine to a three-necked flask equipped with a stirrer, dropping funnel and condensation reflux device, constantly stir , Take 3.7g of epichlorohydrin and use the dropping funnel to drop it within 30min, keep the temperature at 40°C, and stop the reaction after constant temperature reaction for 30h. The product was washed with acetone and dried in vacuo to obtain glycidyl dimethyl hexadecyl ammonium chloride.

(3) Preparation of carboxypropyl chitosan: join 1.61g chitosan in 250mL flask, add 10mL isopropanol to swell, add 2.5mL 10mol/L sodium hydroxide solution, continue to stir for 30min, in- Stir overnight at 25°C, add 9.5g of sodium chlorobutyrate, heat the reaction mixture to 30°C after the addition is complete, and continue stirring for 12 hours. After the reaction was completed, the reaction mixture was filtered to obtain a solid product. The product was washed three times with 80% ethanol and absolute ethanol, and dried in a drying oven at 60°C. The solid was dissolved in water, dialyzed for 4 days, and freeze-dried to obtain a solid product. N,O-carboxypropyl chitosan.

(4) Preparation of quaternized carboxypropyl chitosan: Weigh 3.21g of N,O-carboxypropyl chitosan in a three-necked flask, add 40mL of distilled water, adjust pH=8～10 with sodium hydroxide solution, The temperature was raised to 45°C, and the reaction was performed at a constant temperature for 1h. Dissolve 2.86g of glycidyl dimethyl hexadecyl ammonium chloride in 20mL of water and add dropwise to the reaction system through a constant pressure funnel, raise the temperature to 60°C, and react for 24h. After the reaction was completed, the reaction solution was dialyzed for 5 days, and freeze-dried to obtain a solid product, quaternized carboxypropyl chitosan.

(5) Reaction of modified polyethylene glycol monomethyl ether and quaternized carboxypropyl chitosan: take 0.64g of quaternized carboxypropyl chitosan and place it in a 250mL three-necked flask, add 30mL water to dissolve, and dissolve 1.1 Dissolve 1 g of formylated polyethylene glycol monomethyl ether (Mn=1000) in 10 mL of water, add an appropriate amount of potassium carbonate to adjust the pH of the solution to 6, then add 0.183 g of sodium borohydride, drop it within 10 minutes, stir and heat up to 80°C , constant temperature reaction 8h. Pour the reaction solution into a saturated ammonium sulfate solution to precipitate, filter with suction, wash the filtrate several times with ethanol and acetone, and then dry it in vacuum to obtain the target product—quaternized carboxypropyl grafted with polyethylene glycol monomethyl ether Chitosan, as demulsifier3.

Example 4

A kind of preparation of polyether grafted chitosan derivative crude oil desalination demulsifier, concrete steps are as follows:

(1) Formylation modification of polyethylene glycol monomethyl ether terminal hydroxyl group: Take polyethylene glycol monomethyl ether (Mn=5000) 5g (1mmol) and dissolve it in 30mL of anhydrous dimethyl sulfoxide and chloroform 2mL In the solution, keep the reaction under nitrogen atmosphere, add 1.1mL (10mmol) acetic anhydride solution under constant stirring at room temperature, raise the temperature to 35°C, and react at constant temperature for 15h. After the reaction was completed, the reaction liquid was added to 400 mL of anhydrous ether, and the obtained precipitate was dissolved in chloroform and then recrystallized with ether solution (repeat this step once), and then vacuum-dried at room temperature for 24 hours to obtain the hydroformylated polyethylene glycol monomethyl ether .

(2) Preparation of glycidyl dimethyl docosyl ammonium chloride: add 2.97g docosyl dimethyl tertiary amine to the three-necked flask equipped with agitator, dropping funnel and condensing reflux device, Stir continuously, take 3.7g of epichlorohydrin through the dropping funnel and add dropwise within 30min, keep the temperature at 40°C, and react at constant temperature for 30h. The reaction was stopped, and the product was rinsed with acetone and dried in vacuo to obtain glycidyl dimethyl tridodecyl ammonium chloride.

(3) Preparation of carboxynonyl chitosan: Add 1.61g of chitosan to a 250mL flask, add 10mL of isopropanol to swell, add 2.5mL of 10mol/L sodium hydroxide solution, continue stirring for 30min, and Stir overnight at 20°C, add 14.8g of sodium chlorodecanoate, heat the reaction mixture to 60°C after the addition is complete, and continue stirring for 3h. After the reaction was completed, the reaction mixture was filtered to obtain a crude product. The product was washed three times with 80% ethanol and absolute ethanol, and dried in a drying oven at 60° C. for one day. The solid was dissolved in water and dialyzed for 3 days, and freeze-dried to obtain N, O-carboxynonyl chitosan.

(4) Preparation of quaternized carboxynonyl chitosan: Weigh 3.21g N,O-carboxymethyl chitosan in a three-necked flask, add 40mL dimethyl sulfoxide, and adjust pH=8 with sodium hydroxide solution ~10°C, heat up to 50°C, and react at a constant temperature for 1h (to allow the carboxymethyl chitosan chain to fully open and the grafting to be more uniform); Add it dropwise to the reaction system through a constant pressure funnel, raise the temperature to 80°C, and react for 8 hours. After the reaction is completed, the reaction liquid is dialyzed for 3 to 5 days, and freeze-dried to obtain a solid product of quaternized carboxynonyl chitosan.

(5) Reaction of modified polyethylene glycol monomethyl ether with quaternized carboxynonyl chitosan: take 1.05 g of quaternized carboxynonyl chitosan and place it in a 250 mL three-neck flask, add 30 mL of water to dissolve, and dissolve 5 g Dissolve aldylated polyethylene glycol monomethyl ether (Mn=5000) in 10 mL of water, add an appropriate amount of potassium carbonate to adjust the pH of the solution to 6, then add 0.183 g of sodium borohydride, dropwise within 10 minutes, stir and heat up to 65 °C, Constant temperature reaction 8h. Pour the reaction solution into a saturated ammonium sulfate solution to precipitate, filter with suction, wash the filtrate several times with ethanol and acetone, and then dry it in vacuum to obtain the target product—quaternized carboxynonyl grafted with polyethylene glycol monomethyl ether Chitosan, as demulsifier4.

Comparative Example 1

Get the quaternized carboxymethyl chitosan prepared by step (4) in Example 1 as the demulsifier comparative example 1.

Comparative Example 2

A polysaccharide natural polymer modified crude oil demulsifier prepared according to the method of Example 1 in the announcement text of Chinese patent application CN201310289037.6 was used as demulsifier comparative example 2.

Comparative Example 3

Taking the commercially available brand name as JL series demulsifier as demulsifier comparative example 3

Demulsifier Demulsification Effect Experiment

The crude oil provided by Wuhan Branch of China Petroleum & Chemical Corporation was used as the oil for the demulsification experiment of the present invention. It was measured according to GB/T 8929-88 (distillation method), and the water content in the crude oil was measured to be 50%.

Set the dehydration temperature at 60-80°C, and the concentration of demulsifier in crude oil at 70-120ppm. With reference to the Petroleum and Natural Gas Industry Standard SY/T 5281-2000 of the People's Republic of China "Crude Oil Demulsifier Performance Test Method (Bottle Test Method)", the demulsifiers 1-4 and comparative examples prepared in Examples 1-4 were prepared respectively The demulsifier comparative example 1-3 demulsification performance is tested, and the vibration method of dehydration test bottle adopts mechanical vibration method in the test.

The specific steps are as follows: pour the crude oil emulsion sample into a 100mL stoppered measuring cylinder, and heat it in a constant temperature water bath for 30 minutes; add a certain amount of crude oil demulsifier solution into the stoppered measuring cylinder with a pipette; The time is 5 minutes. After fully mixing, put the stoppered measuring cylinder back in the constant temperature water bath and let it settle; start timing, record the dehydration amount at different times (5min, 15min, 30min, 60min, 120min), and observe and record when the settlement is terminated. Sewage color and oil-water interface condition.

The experimental results show that, compared with the demulsifier comparative examples 1-3, the demulsifier 1-4 obtained according to the method of the present invention has a better performance when the dehydration temperature is 60-80°C and the demulsifier concentration is 70-120ppm. The effect of dehydration and desalination is the best, especially when the concentration is 70ppm and the dehydration temperature is 60℃.

For the demulsifier 1-4 prepared in Example 1-4 and the demulsifier Comparative Example 1-3 provided in Comparative Example 1-3, under the above-mentioned optimal concentration and temperature conditions, the demulsification and dehydration experiment results are shown in Table 1. The results of the milk desalination experiment are shown in Table 2.

Table 1

Table 2

Claims (10)

1. the preparation method of a polyether grafting chitosan derivatives crude oil desalting demulsifier, it is characterised in that include following step Rapid:

1) poly glycol monomethyl ether terminal hydroxy group is carried out aldehyde grouping modified hydroformylation modified poly (ethylene glycol) monomethyl ether；

2) preparation of glycidyl dimethyl alkyl ammomium chloride: drip epoxychloropropane in N, N dimethyl alkylamine, rise Warm to 25 DEG C～40 DEG C, isothermal reaction 6～30h, product is isolated and purified, obtain glycidyl dimethyl alkyl chlorination Ammonium；In wherein said N, N dimethyl alkylamine, the carbon chain lengths of alkyl is C₆‐C₃₄；

3) preparation of quaternized carboxyalkyl chitosan: use solvent orange 2 A to dissolve carboxyalkyl chitosan, uses alkali liquor regulation pH value of solution Value, then by step 2) the glycidyl dimethyl alkyl ammomium chloride of gained drops to reaction system after being dissolved in solvent orange 2 A, heats up To 60～80 DEG C, after reaction 8～24h, reactant liquor is dialysed, lyophilization, obtain quaternized carboxyalkyl chitosan；

4) modified poly (ethylene glycol) monomethyl ether and quaternized carboxyalkyl chitosan reaction: by step 3) the quaternized carboxyalkyl shell prepared Polysaccharide is dissolved in solvent B, then by step 1) to use solvent B to be added drop-wise to after dissolving anti-for the hydroformylation modified poly (ethylene glycol) monomethyl ether for preparing Answer in system, add appropriate alkaline liquor regulation solution ph within the specific limits, add a certain amount of reducing agent, be warming up to 50～ 80 DEG C, isothermal reaction 6～12h, reactant liquor is separated after purification, and lyophilization obtains the quaternized carboxylic of poly glycol monomethyl ether grafting Alkyl chitosan.

The preparation method of polyether grafting chitosan derivatives crude oil desalting demulsifier the most according to claim 1, its feature It is step 1) modified the concretely comprising the following steps of described hydroformylation: 1 part of poly glycol monomethyl ether of molar part is dissolved in solvent C, keeps Reaction is in inert gas environment, and room temperature adds 5～20 molar part aldehyde radical reagent under the conditions of being stirred continuously, and is warming up to 15～35 DEG C, isothermal reaction 5～15h, after isolated and purified for reactant liquor, vacuum drying obtains hydroformylation poly glycol monomethyl ether；Wherein, described The equal molecular mass of number of poly glycol monomethyl ether is 350,500,750,1000,1900 or 5000.

The preparation method of polyether grafting chitosan derivatives crude oil desalting demulsifier the most according to claim 2, its feature It is:

Described solvent C is one or more in dichloromethane, chloroform, dimethyl sulfoxide, ether；

Described aldehyde radical reagent is acetic anhydride；

Described noble gas is nitrogen or argon；

Described isolated and purified for join in absolute ether by reactant liquor, the precipitation chloroform obtained dissolves uses diethyl ether solution weight again Crystallize and repeat this step once.

The preparation method of polyether grafting chitosan derivatives crude oil desalting demulsifier the most according to claim 1, its feature It is, step 2) in, described N, N-dimethyl alkylamine is 1.93～2.97:3.7 with the mass fraction ratio of epoxychloropropane.

The preparation method of polyether grafting chitosan derivatives crude oil desalting demulsifier the most according to claim 1, its feature Be step 3) described in the preparation method of carboxyalkyl chitosan be:

By weight, by swelling for 1.61 parts of chitosans, using alkali liquor regulation suspension is alkalescence, under the conditions of-15 DEG C～-25 DEG C Stirred overnight, adds 7.4～14.8 parts of carboxylated reagent chloro alkyl acid sodium, is warmed up to 30～60 DEG C of stirring reactions 3～12h, Product is isolated and purified, and lyophilization obtains carboxyalkyl chitosan；Wherein, the carbon chain lengths of described chloro alkyl acid sodium is C₂-C₁₀。

The preparation method of polyether grafting chitosan derivatives crude oil desalting demulsifier the most according to claim 1, its feature It is, step 3) in, described carboxyalkyl chitosan with the mass fraction ratio of glycidyl dimethyl alkyl ammomium chloride is 3.21:1.93～7.7.

The preparation method of polyether grafting chitosan derivatives crude oil desalting demulsifier the most according to claim 1, its feature It is, step 3) in, described pH value range is 8～10；Step 4) in, described pH value range is 5～7.

The preparation method of polyether grafting chitosan derivatives crude oil desalting demulsifier the most according to claim 1, its feature It is, step 3) in, after carboxyalkyl chitosan employing solvent orange 2 A is dissolved and uses alkali liquor regulation solution ph then this is molten Liquid is warming up to 45～50 DEG C, isothermal reaction 1h.

The preparation method of polyether grafting chitosan derivatives crude oil desalting demulsifier the most according to claim 1, its feature Be, step 4) in, described quaternized carboxyalkyl chitosan, aldehyde grouping modified poly glycol monomethyl ether and reducing agent matter Amount portion rate is: (0.47～1.05): (0.35～5): (0.08～0.183).

The preparation method of polyether grafting chitosan derivatives crude oil desalting demulsifier the most according to claim 1, its feature It is,

Described solvent orange 2 A is distilled water, isopropanol, sodium hydroxide solution, hydrochloric acid solution, DMF, N, N dimethyl The mixing of one or more in acetamide, dimethyl sulfoxide, acetic acid, methanol；

Described solvent B is distilled water, isopropanol, aqueous sodium carbonate, DMF, N,N-dimethylacetamide, One or more in acetic acid, ethanol, methanol, acetone, saturated ammonium sulfate solution；

Step 4) described in reducing agent include but not limited to sodium borohydride or sodium cyanoborohydride.