CN109181367B

CN109181367B - Method for preparing transparent zinc oxide liquid phase dispersion

Info

Publication number: CN109181367B
Application number: CN201811148029.9A
Authority: CN
Inventors: 陈建峰; 黄谢君; 曾晓飞; 王洁欣
Original assignee: Beijing University of Chemical Technology
Current assignee: Beijing University of Chemical Technology
Priority date: 2018-09-29
Filing date: 2018-09-29
Publication date: 2020-12-11
Anticipated expiration: 2038-09-29
Also published as: CN109181367A

Abstract

The invention discloses a method for preparing transparent zinc oxide liquid-phase dispersion, which comprises the following steps: 1) dissolving salt in a liquid-phase medium A to obtain a salt solution; dissolving alkali in the liquid phase medium B to obtain an alkali solution; the salt is zinc salt or mixed zinc salt, and the mixed zinc salt is formed by mixing zinc salt and salt of a doping element in a molar ratio of 10-100: 1; 2) adding a salt solution and an alkali liquor into a supergravity rotating packed bed reactor, and reacting at a certain temperature to obtain a zinc oxide suspension; 3) adding a surface coating agent into the zinc oxide suspension, and modifying and coating for a period of time at a certain temperature; 4) and precipitating, centrifuging and washing the standing modification solution, and dispersing into a liquid phase medium C to obtain the zinc oxide transparent liquid phase dispersion. The invention is completed in a supergravity rotating packed bed reactor, greatly enhances mass transfer and enhances micro mixing, and the product is transparent and has good dispersibility; good stability, no sedimentation after standing for more than 12 months.

Description

Method for preparing transparent zinc oxide liquid phase dispersion

Technical Field

The invention belongs to the technical field of chemical industry, relates to a preparation method of a liquid phase dispersion, and particularly relates to a method for preparing a transparent zinc oxide liquid phase dispersion.

Background

As an important inorganic nano material, nano zinc oxide has been studied in 90 s of the 20 th century. Nowadays, zinc oxide has a wide range of applications, and besides being widely applied in rubber industry, petrochemical industry and coating industry, zinc oxide can also be applied to electronic laser materials, fluorescent powder additives, magnetic materials, piezoelectric materials, ceramics and the like. In the rubber industry, nano zinc oxide is an important inorganic active material, which not only can reduce the using amount of common zinc oxide, but also can improve the wear resistance and the ageing resistance of rubber products and prolong the service life; in the paint industry, the nano zinc oxide can greatly improve the covering power and the tinting strength of paint products, can also improve other indexes of the paint, and can be applied to preparing functional nano paint; in addition, in the aspect of ceramic industry, the addition of the nano zinc oxide ensures that the ceramic product has self-cleaning functions of decomposing organic matters, sterilizing and deodorizing, and ensures the quality of the product.

The ultraviolet shielding performance of the nano zinc oxide mainly depends on factors such as morphological characteristics, particle size and dispersion degree. Among them, the particle size distribution and the degree of dispersion of nanoparticles are very important factors. The traditional preparation method is to prepare solid nano zinc oxide powder, add a modifier to modify the surface of the powder, and then fill the powder into a high polymer material to serve as an ultraviolet shielding function. However, the zinc oxide particles prepared by the method are partially agglomerated before modification, so that the particle size is large and the distribution is uneven after modification, and the particle shape is difficult to control, so that the zinc oxide particles are poor in dispersing performance after being refilled into a resin base, and poor in compatibility with a polymer.

The supergravity technology (supergravity rotating packed bed) is a new technology for strengthening mass transfer and micro mixing process by using supergravity environment which is much greater than the acceleration of gravity of the earth, and is obtained by rotating to generate simulated supergravity environment on the earth. It can greatly raise conversion rate and selectivity of reaction, obviously reduce volume of reactor, simplify process and flow process and implement high-effective energy-saving process. In a hypergravity environment, the molecular diffusion and interphase mass transfer processes among molecules with different sizes are much faster than those in the earth gravity field, gas-liquid, liquid-liquid and liquid-solid phases are in flow contact in a porous medium in the hypergravity environment hundreds to thousands of times larger than the earth gravity field, the liquid is broken into nanoscale membranes, filaments and drops by huge shearing force, a huge and rapidly updated phase interface is generated, the interphase mass transfer rate is increased by 1-3 orders of magnitude compared with that in a traditional tower, and the mass transfer process is greatly enhanced.

The existing method for preparing nano zinc oxide by adopting a supergravity technology uses zinc chloride and sodium hydroxide as raw materials, adopts a supergravity (rotary packed bed) technology, adopts a liquid-liquid phase reaction mode, and then prepares nano zinc oxide powder by filtering, washing and drying, and has the defect that the prepared zinc oxide has larger particle size, and the minimum particle size is 68 nm.

In the prior art, the preparation of the nano zinc oxide powder uses zinc nitrate and ammonia water as raw materials to prepare a precursor, and zinc oxide powder is obtained through high-temperature ultrasound, drying and calcining, and the process has the defect that the prepared zinc oxide has a large particle size of 20-200 nm.

Therefore, the invention provides a method for preparing transparent zinc oxide liquid-phase dispersion, which adopts a supergravity rotating packed bed to greatly strengthen mass transfer and micro mixing, and the prepared zinc oxide particles have controllable appearance and uniform particle size distribution.

Disclosure of Invention

It is an object of the present invention to provide a process for preparing transparent zinc oxide liquid phase dispersions. The method adopts a supergravity rotating packed bed, so that mass transfer and micro mixing can be greatly enhanced, the prepared zinc oxide particles have controllable appearance and uniform particle size distribution, the solid content of the transparent zinc oxide liquid phase dispersion prepared by further modifying the zinc oxide particles prepared by the method can reach 70 wt%, the zinc oxide crystals have small particle size and uniform distribution, and the one-dimensional size is 3-10 nm; in addition, the product has good dispersion effect and good stability, does not settle after standing for months, takes water and various organic solvents as liquid phase dispersion media, and has wide application range; the method well solves the problem of poor dispersion performance and compatibility of the nano zinc oxide in application, thereby endowing the product with higher application performance and added value.

In order to achieve the purpose, the invention adopts the following technical scheme:

a process for preparing a transparent zinc oxide liquid phase dispersion comprising the steps of:

1) dissolving salt in a liquid-phase medium A to obtain a salt solution; dissolving alkali in the liquid phase medium B to obtain an alkali solution;

the salt is zinc salt or mixed zinc salt, and the mixed zinc salt is formed by mixing zinc salt and salt of a doping element in a molar ratio of 10-100: 1;

2) adding a salt solution and an alkali liquor into a supergravity rotating packed bed reactor, and reacting to obtain a zinc oxide suspension;

3) adding a surface coating agent into the zinc oxide suspension for modification coating, and standing the modified solution after modification;

4) precipitating, centrifuging and washing the modification solution after standing, and dispersing into a liquid phase medium C to obtain a zinc oxide transparent liquid phase dispersion;

in step 4), the liquid phase medium C is selected from one or more of the following substances: diesel oil, naphtha, heavy oil, n-heptane, n-octane, JP-10 aviation fuel oil, C4 light hydrocarbon, C5 light hydrocarbon, vacuum distillate oil, coker gas oil, atmospheric residue and vacuum residue.

Wherein the heavy oil refers to residual heavy oil obtained after gasoline and diesel oil are extracted from crude oil; the atmospheric residue oil and the vacuum residue oil respectively refer to residual oil obtained by atmospheric distillation and vacuum distillation of crude oil; coker gas oil refers to the bottoms oil produced from a coker unit for use as fuel (marine).

Preferably, in step 1), the zinc salt is selected from one or more of the following: zinc chloride, zinc bromide, zinc nitrate, zinc sulfate and zinc acetate; the salt of the doping element is selected from one or more of the following substances: aluminum sulfate, aluminum nitrate, aluminum acetate, aluminum isopropoxide, aluminum chloride, gallium nitrate, gallium sulfate, indium acetate, indium nitrate, indium chloride, tin chloride, and tin acetate; the base is selected from one or more of the following: lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonia monohydrate.

Preferably, the concentration of the zinc salt in the step 1) is 0.05 mol/L-1 mol/L, and the concentration of the zinc salt is preferably 0.15 mol/L-0.6 mol/L;

preferably, the concentration of the alkali liquor in the step 1) is 0.1-2 mol/L, and preferably the concentration of the alkali liquor is 0.3-1.2 mol/L.

Preferably, said liquid-phase medium a in step 1) is selected from one or more of the following: water, methanol, ethanol, ethylene glycol, isopropanol, butanol, benzyl alcohol, glycerol, diethyl ether, dimethyl ether, acetone, butanone and cyclohexanone; the liquid phase medium B is selected from one or more of the following substances: water, methanol, ethanol, ethylene glycol, isopropanol, glycerol, butanol, acetone, butanone, ethyl acetate, butyl acetate, toluene, xylene, dimethyl sulfoxide, tetrahydrofuran, n-hexane, cyclohexane.

Preferably, the reaction temperature in the step 2) is 20-85 ℃; more preferably, the reaction temperature is 25-75 ℃; most preferably, the reaction temperature is 40-70 ℃.

Preferably, in the step 2), the high-gravity rotating bed reactor is selected from a rotating packed bed high-gravity rotating bed reactor, a baffled high-gravity rotating bed reactor, a spiral channel high-gravity rotating bed reactor, a stator-rotor high-gravity rotating bed reactor or a rotating disc high-gravity rotating bed reactor; preferably, the rotating speed of a rotor of the rotating bed is 300-5000 rpm; more preferably, the rotating speed of the rotor of the rotating bed is 600-2600 rpm.

Preferably, in the step 2), the volume flow ratio of the salt solution and the alkali liquor introduced into the rotating packed bed is 0.2-3.5: 1; the feeding flow of the salt solution into the rotary packed bed is 50 ml/min-1000 ml/min, and the alkali liquor is 40 ml/min-800 ml/min.

Preferably, in step 3), the surface coating agent is selected from one or more of the following: titanate, aluminate, silicate, stearic acid, sodium stearate, oleic acid, polyvinylpyrrolidone, gamma-methacryloxypropyltrimethoxysilane, polyethylene glycol, polyvinyl alcohol, octadecylamine, gamma- (methacryloyloxy) propyltrimethoxysilane, gamma-aminopropyltriethoxysilane, gamma-glycidoxypropyltrimethoxysilane, n-octyltrimethoxysilane, dodecyltrimethoxysilane, octadecyltrimethoxysilane, 3-aminopropyltrimethoxysilane, phenyltrimethoxysilane, methyldichlorosilane. The present inventors have found that the choice of the coating agent depends on the dispersion medium, each dispersion medium needs to have an appropriate coating agent formulation corresponding to it, and that the use of an inappropriate surface coating agent, or an inappropriate ratio of coating agents and amounts of coating agents, may lead to difficulties in the final formation of the dispersion or instability of the dispersion.

Preferably, the mass ratio of the surface coating agent to the zinc oxide in the step 3) is 0.1-2: 1.

Preferably, when the surface coating agent in step 3) is multiple, the surface coating agent is added in a mixing manner at one time or different surface coating agents are added in different times.

Preferably, the time interval of adding the surface coating agent in the step 3) in several times is 5 min-2 h, preferably 10 min-1 h.

Preferably, the number of times of adding the surface coating agent in step 3) is 2-3 times.

Preferably, when the surface coating agent is added in step 3) in several times, one or two surface coating agents are added each time; preferably, when two surface coating agents are added at each time, the ratio of the two coating agents is adjusted through a plurality of tests according to actual needs.

The invention discovers that when the coating agent is added by mixing once, different coating agents simultaneously form a coating layer on the surface of the particles, and the groups of the coating layer exposed on the surface are mixed groups. Different groups have different polarities, and the surface polarity smoothness of the coating layer is adjusted by adjusting the proportion of a plurality of coating agents with different polarities, so that the nano zinc oxide can be dispersed in solvents with different polarities.

The multiple times of adding at different time intervals are adopted in the invention to form a multilayer coating layer, the other one is added after the previous coating agent completely reacts, so that the new surface is more beneficial to coating, the other one is added after the previous coating agent reacts for a part, so that the coating amount of different coating agents is favorably adjusted, the surface property of the nano-particles is accurately adjusted and controlled, the nano-particles can be more suitable for a solvent molecular system of a dispersion medium, and the particles are dispersed more stably; on the other hand, the activity of the nano particles is regulated by multilayer coating, and the later practical application is facilitated. It has also been found in the present invention that the nature of the surface of the particles depends on the group coating the outermost layer, i.e. the group of the coating agent added last, the first few of the multiple additions being used to modulate the activity of the particles in later applications.

Preferably, in the step 3), the modification time is 5min to 6 hours, preferably 20min to 3 hours; the modification temperature is 40-90 ℃, and preferably 50-80 ℃.

Preferably, in the step 3), the standing time after the reaction is finished is 2 to 48 hours, preferably 10 to 24 hours.

Preferably, in step 4), the dispersion is ultrasonic dispersion.

Preferably, in the step 4), the solid content in the transparent zinc oxide liquid-phase dispersion is 1 wt% to 70 wt%; further, the solid content is 40 wt% -70 wt%, 45 wt% -70 wt%, 50 wt% -70 wt%, 55 wt% -70 wt%, 60 wt% -70 wt% and the like; more preferably, the solids content is 70% by weight.

Preferably, in the step 4), in the transparent zinc oxide liquid phase dispersion, the zinc oxide crystals have small particle size and uniform distribution, and the one-dimensional size is 3-10 nm; further, the one-dimensional size is 3-8 nm, 3-7 nm, 3-6 nm, 3-5nm, 3-4 nm, etc.

The transparent zinc oxide liquid phase dispersion can be used as a filler of rubber, paint, plastics, fabrics and other polymers, and can also be used as an additive of cosmetics, oil products and the like, and can also be used for photocatalytic decomposition of organic matters to treat industrial and domestic wastewater.

The invention is based on the basic principle that zinc salt solution or mixed zinc salt solution and alkali liquor react in a supergravity rotating packed bed reactor, mass transfer is greatly enhanced, micro mixing is enhanced, and then nano zinc oxide suspension is prepared, the surface of zinc oxide particles in the suspension reacts with a surface coating agent to form a coating layer, and transparent zinc oxide liquid phase dispersion is obtained after filtration, washing and dispersion, wherein the dispersion medium is water or an organic solvent.

The surface coating agent forms a coating on the surface of the particles, which is beneficial to forming zinc oxide particles which are monodisperse in a water phase or an organic phase. A large number of hydroxyl groups exist on the surface of the nano zinc oxide and react with the surface coating agent, and large steric hindrance exists between large organic groups brought by the active agent coated on the surface of the nano zinc oxide, so that the nano particles are not easy to agglomerate. The selection of a suitable surface coating agent and dispersion medium is important. Meanwhile, the invention needs to carry out more complex processes such as precipitation reaction, surface modification reaction, redispersion process and the like, so that the selection of a proper surface coating agent and the control of the proportion, the reaction rate, the time and the like of the raw materials are all technical difficulties to be solved.

In addition, unless otherwise specified, any range recited herein includes any value between the endpoints and any sub-range defined by any value between the endpoints or any value between the endpoints.

The invention has the following beneficial effects:

1) the process of preparing the particles is completed in the supergravity rotating packed bed reactor, so that the mass transfer and the micromixing are greatly enhanced, and in addition, the zinc oxide is dispersed in a liquid phase medium through a proper surface coating agent to form a stable and transparent dispersoid. The dispersion can see obvious Tyndall phenomenon, the transparent nano zinc oxide dispersion can see obvious Tyndall phenomenon, and the product is transparent and has good dispersibility;

2) the zinc oxide crystals in the transparent zinc oxide liquid phase dispersion body have small grain size and uniform distribution, and the minimum one-dimensional size is 3 nm.

3) The transparent zinc oxide liquid phase dispersion can still maintain higher transparency and ultraviolet shielding capability under high concentration.

4) The solid content of the transparent zinc oxide liquid-phase dispersion prepared by the invention can be adjusted by changing the process conditions such as raw material proportion, reaction time, reaction temperature and the like. The solid content of the prepared product can reach 70 wt%. The product is transparent and has good stability. The product synthesized by the invention has good stability and does not settle after standing for 12 months. The method has the advantages of simple process flow, easy operation, high repeatability, good product quality and easy amplification.

Drawings

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

FIG. 1 shows a transmission electron micrograph of the transparent zinc oxide liquid phase dispersion obtained in example 1 of the present invention.

FIG. 2 shows a UV-Vis spectrum of the transparent zinc oxide liquid-phase dispersion obtained in inventive example 1.

FIG. 3 shows the X-ray diffraction pattern of the transparent zinc oxide liquid-phase dispersion obtained in example 1 of the present invention.

Detailed Description

In order to more clearly illustrate the invention, the invention is further described below with reference to preferred embodiments and the accompanying drawings. Similar parts in the figures are denoted by the same reference numerals. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and is not to be taken as limiting the scope of the invention.

In the description of the present invention, "a plurality" means two or more unless otherwise specified; the terms "upper", "lower", "left", "right", "inner", "outer", "front", "rear", "head", "tail", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, should not be construed as limiting the invention.

Example 1

The preparation of transparent zinc oxide liquid phase dispersion comprises the following steps:

1) adding 1000g of zinc acetate methanol mixed solution A with the mass concentration of 11% into a reactant storage tank A, stirring, dissolving and heating to 70 ℃; adding 1000g of potassium hydroxide ethanol mixed solution B with the mass concentration of 5.26% into a reactant storage tank B, stirring, dissolving and heating to 55 ℃;

2) starting circulating water at 70 ℃ to heat the bed body of the super-gravity rotating bed, starting the rotating bed after the temperature is stable, and adjusting the rotating speed to 1800 rpm; starting a feeding pump, wherein the feeding flow rate is 200ml/min, and simultaneously conveying two reactants into a rotating bed for reaction;

3) after the mixed solution A and the mixed solution B are fed, the suspension obtained by reaction completely flows out of the supergravity rotating device and enters a modification tank, the supergravity rotating device is closed, 6g of tetraethoxysilane coating agent is gradually added into the modification tank, the coating reaction is carried out for 0.5h at 70 ℃, then 20g of coating agent (gamma-methacryloxypropyltrimethoxysilane and oleic acid are mixed according to the mass ratio of 1:1) is gradually added, the temperature of the modification tank is controlled to be 70 ℃, the modification time is 0.5h, and 100g of deionized water is added into the mixed solution obtained after modification and stands for 12 h;

4) adding a large amount of deionized water into the standing modified solution to completely precipitate, centrifuging the suspension, filtering the precipitate under reduced pressure, washing with deionized water and ethanol to obtain a filter cake, transferring the filter cake into a flask, adding a proper amount of diesel oil for dispersion, and removing the residual ethanol by rotary evaporation at 45 ℃. Finally transferring the product to a dispersion tank; and opening an ultrasonic dispersion device of the redispersion tank, conveying 30g of diesel oil into the dispersion tank, and performing ultrasonic dispersion to obtain the zinc oxide/diesel oil transparent dispersion.

As shown in figures 1-3, the product is light blue and transparent, has 50% of solid content, does not settle after standing for 12 months, has a one-dimensional particle size of 5-8nm after detection, and can still maintain high transparency and ultraviolet shielding capability under high concentration.

Example 2

1) adding 1000g of mixed solution A of zinc acetate with the mass concentration of 8% and gallium nitrate methanol with the mass concentration of 0.4% into a reactant storage tank A, stirring, dissolving and heating to 50 ℃; adding 1000g of potassium hydroxide ethanol mixed solution B with the mass concentration of 4% into a reactant storage tank B, and stirring and dissolving at room temperature;

2) starting circulating water at 50 ℃ to heat the bed body of the super-gravity rotating bed, starting the rotating bed after the temperature is stable, and adjusting the rotating speed to 1000 rpm; starting a feeding pump, wherein the feeding flow is 500ml/min, and simultaneously conveying two reactants into a rotating bed for reaction;

3) after the feeding of the zinc salt solution and the alkali liquor is finished, after all the suspension obtained by the reaction flows out of the supergravity rotating device and enters the modification tank, closing the supergravity rotating device, gradually adding 24g of a mixed coating agent (mixed by tetraethoxysilane, octadecylamine and oleic acid in a mass ratio of 2:5:5) into the modification tank, controlling the temperature of the modification tank to be 70 ℃, modifying for 0.5h, and adding 95g of deionized water into the mixed solution obtained after modification and standing for 15 h;

4) adding a large amount of n-hexane into the standing modification liquid to completely precipitate, centrifuging the suspension, filtering the precipitate under reduced pressure, washing the n-hexane to obtain a filter cake, transferring the filter cake into a flask, adding a proper amount of heavy oil to disperse, and removing the residual n-hexane by rotary evaporation at 30 ℃. Finally transferring the product to a dispersion tank; and (3) opening an ultrasonic dispersion device of the redispersion tank, conveying 40g of heavy oil into the redispersion tank, and performing ultrasonic dispersion to obtain the zinc oxide/heavy oil transparent dispersion.

The detection shows that the product is light blue and transparent, the solid content is 30%, the product does not settle after standing for 12 months, and the one-dimensional size of the particles of the dispersion is 8-9 nm.

Example 3

2) starting circulating water at 50 ℃ to heat the bed body of the super-gravity rotating bed, starting the rotating bed after the temperature is stable, and adjusting the rotating speed to 1600 rpm; starting a feeding pump, wherein the feeding flow is 400ml/min, and simultaneously conveying two reactants into a rotating bed for reaction;

3) after the feeding of zinc salt solution and alkali liquor is finished, the suspension obtained by the reaction completely flows out of the supergravity rotating device and enters a modification tank, the supergravity rotating device is closed, 4g of butyl titanate coating agent is gradually added into the modification tank, the coating reaction is carried out for 1h at 70 ℃, then 15g of coating agent (gamma-glycidyl ether oxypropyl trimethoxy silane and polyvinylpyrrolidone are mixed according to the mass ratio of 1: 2) is gradually added, the temperature of the modification tank is controlled to be 70 ℃, the modification time is 0.5h, and 95g of deionized water is added into the mixed solution obtained after the modification and the mixed solution is kept stand for 12 h;

4) adding a large amount of n-hexane into the standing modification solution to completely precipitate, centrifuging the suspension, filtering the precipitate under reduced pressure, washing the n-hexane to obtain a filter cake, transferring the filter cake into a flask, adding a proper amount of vacuum distillate oil for dispersing, and removing the residual n-hexane by rotary evaporation at 30 ℃. Finally transferring the product to a dispersion tank; and opening an ultrasonic dispersion device of the redispersion tank, conveying 40g of vacuum distillate oil into the redispersion tank, and performing ultrasonic dispersion to obtain the zinc oxide/vacuum distillate oil transparent dispersion.

Example 4

1) adding 1000g of mixed solution A of zinc chloride with the mass concentration of 10% and indium chloride ethanol with the mass concentration of 0.7% into a reactant storage tank A, stirring, dissolving and heating to 65 ℃; adding 1000g of sodium hydroxide methanol mixed solution B with the mass concentration of 5% into a reactant storage tank B, stirring, dissolving and heating to 50 ℃;

2) starting circulating water at 65 ℃ to heat the bed body of the super-gravity rotating bed, starting the rotating bed after the temperature is stable, and adjusting the rotating speed to 1800 rpm; starting a feeding pump, wherein the feeding flow rate is 200ml/min, and simultaneously conveying two reactants into a rotating bed for reaction;

3) after the mixed liquor A and the mixed liquor B are fed, the suspension obtained by the reaction completely flows out of the supergravity rotating device and enters a modification tank, the supergravity rotating device is closed, 5g of an ethyl orthosilicate coating agent is gradually added into the modification tank, the coating reaction is carried out for 50min at 70 ℃, then 19g of a coating agent (dodecyl trimethoxy silane and mixed according to the mass ratio of 3: 2) is gradually added, the temperature of the modification tank is controlled to be 60 ℃, the modification time is 1.5h, and 95g of deionized water is added into the mixed liquor obtained after modification and stands for 15 h;

4) adding a large amount of deionized water into the standing modified solution to completely precipitate, centrifuging the suspension, filtering the precipitate under reduced pressure, washing with deionized water and ethanol to obtain a filter cake, transferring the filter cake into a flask, adding a proper amount of JP-10 aviation fuel oil, dispersing, and removing the residual ethanol by rotary evaporation at 35 ℃. Finally transferring the product to a dispersion tank; and (3) opening an ultrasonic dispersion device of the redispersion tank, conveying 45gJP-10 aviation fuel oil into the redispersion tank, and performing ultrasonic dispersion to obtain the zinc oxide/JP-10 aviation fuel oil transparent dispersion.

The detection shows that the product is light blue and transparent, has the solid content of 40 percent, does not settle after standing for 12 months, and has the one-dimensional particle size of 6-8 nm.

Example 5

1) adding 1000g of mixed solution A of zinc nitrate with the mass concentration of 8% and tin acetate ethanol with the mass concentration of 0.7% into a reactant storage tank A, stirring, dissolving and heating to 60 ℃; adding 1000g of potassium hydroxide ethanol mixed solution B with the mass concentration of 4% into a reactant storage tank B, and stirring and dissolving at room temperature;

2) starting circulating water at 50 ℃ to heat the bed body of the super-gravity rotating bed, starting the rotating bed after the temperature is stable, and adjusting the rotating speed to 1200 rpm; starting a feeding pump, wherein the feeding flow rate is 300ml/min, and simultaneously conveying two reactants into a rotating bed for reaction;

3) after the feeding of the mixed liquid A and B is finished, the suspension obtained by the reaction completely flows out of the supergravity rotating device and enters a modification tank, the supergravity rotating device is closed, 4g of methyl aluminate coating agent is gradually added into the modification tank, the coating reaction is carried out for 0.5h at the temperature of 60 ℃, then 16g of n-octyl trimethoxy silane is gradually added into the coating agent, the temperature of the modification tank is controlled to be 60 ℃, the modification time is 0.5h, 95g of deionized water is added into the mixed liquid obtained after the modification, and the mixture is kept still for 10 h;

4) adding a large amount of deionized water into the standing modified solution to completely precipitate, centrifuging the suspension, filtering the precipitate under reduced pressure, washing with deionized water and ethanol to obtain a filter cake, transferring the filter cake into a flask, adding a proper amount of n-heptane for dispersion, and removing the residual ethanol by rotary evaporation at 35 ℃. Finally transferring the product to a dispersion tank; and (3) opening an ultrasonic dispersion device of the redispersion tank, conveying 20g of n-heptane to the redispersion tank, and performing ultrasonic dispersion to obtain the zinc oxide/n-heptane transparent dispersion.

Through detection, the product is light blue and transparent, the solid content is 70%, the product does not settle after standing for 12 months, and the one-dimensional size of the particles of the dispersion is 3-5 nm.

Example 6

1) adding 1000g of mixed solution A of zinc acetate with the mass concentration of 8% and aluminum acetate with the mass concentration of 0.7% into a reactant storage tank A, stirring, dissolving and heating to 50 ℃; adding 1000g of potassium hydroxide ethanol mixed solution B with the mass concentration of 4% into a reactant storage tank B, and stirring and dissolving at room temperature;

2) starting circulating water at 50 ℃ to heat the bed body of the super-gravity rotating bed, starting the rotating bed after the temperature is stable, and adjusting the rotating speed to 1800 rpm; starting a feeding pump, wherein the feeding flow rate is 300ml/min, and simultaneously conveying two reactants into a rotating bed for reaction;

3) after the mixed solution A and the mixed solution B are fed, the suspension obtained by the reaction completely flows out of the supergravity rotating device and enters a modification tank, the supergravity rotating device is closed, 4g (mass ratio is 1:1) of butyl borate and tetraethoxysilane coating agent are gradually added into the modification tank, coating reaction is carried out for 0.5h at the temperature of 60 ℃, then 16g of n-octyl trimethoxy silane is gradually added into the modification tank, the temperature of the modification tank is controlled to be 60 ℃, the modification time is 50min, and 95g of deionized water is added into the mixed solution obtained after modification and stands for 15 h;

4) adding a large amount of deionized water into the standing modified solution to completely precipitate, centrifuging the suspension, filtering the precipitate under reduced pressure, washing with deionized water and ethanol to obtain a filter cake, and transferring the filter cake to a dispersion tank; and (3) starting an ultrasonic dispersion device of the redispersion tank, conveying 50g of atmospheric residue oil into the redispersion tank, and performing ultrasonic dispersion to obtain the zinc oxide/atmospheric residue oil transparent dispersion.

The detection shows that the product is light blue and transparent, the solid content is 30%, the product does not settle after standing for 12 months, and the one-dimensional size of the particles of the dispersion is 6-10 nm.

Example 7

1) adding 1000g of mixed solution A of zinc acetate with the mass concentration of 10% and aluminum isopropoxide methanol with the mass concentration of 0.1% into a reactant storage tank A, stirring, dissolving and heating to 60 ℃; adding 1000g of sodium hydroxide ethanol mixed solution B with the mass concentration of 5% into a reactant storage tank B, stirring, dissolving and heating to 45 ℃;

2) starting circulating water at 60 ℃ to heat the bed body of the super-gravity rotating bed, starting the rotating bed after the temperature is stable, and adjusting the rotating speed to 800 rpm; starting a feeding pump, wherein the feeding flow is 400ml/min, and simultaneously conveying two reactants into a rotating bed for reaction;

3) after the mixed liquid A and B are fed, the suspension obtained by reaction completely flows out of the supergravity rotating device and enters a modification tank, the supergravity rotating device is closed, 5g of tetraethoxysilane coating agent is gradually added into the modification tank, the coating reaction is carried out for 20min at 70 ℃, then 19g of coating agent is gradually added (the mass ratio of gamma-aminopropyl triethoxysilane to octadecyltrimethoxysilane is 1:3, the mixture is mixed), the temperature of the modification tank is controlled to be 70 ℃, the modification time is 2h, and 95g of deionized water is added into the mixed liquid obtained after modification and stands for 12 h;

4) adding a large amount of deionized water into the standing modified solution to completely precipitate, centrifuging the suspension, filtering the precipitate under reduced pressure, washing with deionized water and ethanol to obtain a filter cake, transferring the filter cake into a flask, adding a proper amount of reduced pressure residual oil to disperse, and removing the residual ethanol by rotary evaporation at 35 ℃. Finally transferring the product to a dispersion tank; and opening an ultrasonic dispersion device of the redispersion tank, conveying 45g of vacuum residue oil to the redispersion tank, and performing ultrasonic dispersion to obtain the zinc oxide/vacuum residue oil transparent dispersion.

Example 8

1) adding 1000g of zinc acetate methanol mixed solution A with the mass concentration of 15% into a reactant storage tank A, stirring, dissolving and heating to 70 ℃; adding 1000g of sodium hydroxide ethanol mixed solution B with the mass concentration of 8% into a reactant storage tank B, stirring, dissolving and heating to 70 ℃;

2) starting circulating water at 70 ℃ to heat the bed body of the super-gravity rotating bed, starting the rotating bed after the temperature is stable, and adjusting the rotating speed to 1800 rpm; starting a feeding pump, wherein the feeding flow is 600ml/min, and simultaneously conveying two reactants into a rotating bed for reaction;

3) after the mixed solution A and the mixed solution B are fed, the suspension obtained by the reaction completely flows out of the supergravity rotating device and enters a modification tank, the supergravity rotating device is closed, 20g of coating agent oleic acid is gradually added into the modification tank, the temperature of the modification tank is controlled to be 60 ℃, the modification time is 1h, 95g of deionized water is added into the mixed solution obtained after modification, and the mixture is kept still for 15 h;

4) adding a large amount of deionized water into the standing modified solution to completely precipitate, centrifuging the suspension, filtering the precipitate under reduced pressure, washing with deionized water and ethanol to obtain a filter cake, transferring the filter cake into a flask, adding a proper amount of petroleum ether to disperse, and removing the residual ethanol by rotary evaporation at 35 ℃. Finally transferring the product to a dispersion tank; and (3) starting an ultrasonic dispersion device of the redispersion tank, conveying 45g of naphtha to the redispersion tank, and performing ultrasonic dispersion to obtain the zinc oxide/naphtha transparent dispersion.

The detection shows that the product is light blue and transparent, has the solid content of 40 percent, does not settle after standing for 12 months, and has the one-dimensional particle size of 4-6 nm.

Comparative example 1

A transparent zinc oxide liquid phase dispersion was prepared using the procedure as described in example 1, except that: 6g of ethyl orthosilicate is added firstly in the step 3), and 20g of gamma-methacryloxypropyltrimethoxysilane is added, and the obtained results are shown in a table 1.

Comparative example 2

A transparent zinc oxide liquid phase dispersion was prepared using the procedure as described in example 1, except that: in the step 3), 6g of methyl aluminate is added firstly, and 20g of oleic acid is added, and the obtained results are shown in the table 1.

Comparative example 3

A transparent zinc oxide liquid phase dispersion was prepared using the procedure as described in example 1, except that: in the step 3), 6g of butyl titanate is firstly added, and 20g of octadecyl trimethoxy silane is then added, and the obtained results are shown in the table 1.

Comparative example 4

A transparent zinc oxide liquid phase dispersion was prepared using the procedure as described in example 1, except that: 6g of tetraethoxysilane is added firstly in the step 3), and 20g of 3-aminopropyltriethoxysilane is added, and the obtained results are shown in Table 1.

Comparative example 5

A transparent zinc oxide liquid phase dispersion was prepared using the procedure as described in example 1, except that: in the step 3), 6g of methyl aluminate is added firstly, and 20g of coating agent (3-aminopropyl triethoxysilane and octadecyl trimethoxysilane are added in a mass ratio of 1:1) are added, and the obtained results are shown in a table 1.

Comparative example 6

A transparent zinc oxide liquid phase dispersion was prepared using the procedure as described in example 1, except that: 6g of tetraethoxysilane is added firstly in the step 3), and 20g of coating agent is added (gamma-methacryloxypropyltrimethoxysilane and oleic acid are mixed according to the mass ratio of 2: 1), and the obtained results are shown in a table 1.

Comparative example 7

A transparent zinc oxide liquid phase dispersion was prepared using the procedure as described in example 1, except that: 6g of tetraethoxysilane is added firstly in the step 3), and 20g of coating agent is added (gamma-methacryloxypropyltrimethoxysilane and oleic acid are mixed according to the mass ratio of 1:1), and the obtained results are shown in a table 1.

Comparative example 8

TABLE 1 transparent zinc oxide liquid dispersions prepared with different surface coating agents

Example 1 zinc oxide was dispersed in a liquid phase medium by a suitable surface coating agent to form a stable transparent dispersion. The choice of capping agent depends on the dispersion medium, each dispersion medium requires a specific capping agent to be associated with it, the use of an inappropriate surface capping agent, or an inappropriate ratio of capping agents and amounts of capping agents can lead to difficulties in the final formation of the dispersion or instability of the dispersion.

As can be seen from Table 1, compared with example 1, the coating agent added for the second time in comparative example 1 is only gamma-methacryloxypropyltrimethoxysilane and does not contain oleic acid, so that the surface property of the particles does not accord with the property of diesel oil, and the final modified particles are poor in dispersion in the diesel oil and have an agglomeration phenomenon; compared with example 1, comparative example 2 uses oleic acid as the coating agent for the second time, directly resulting in no dispersion at the end; compared with the example 1, the comparative example 3 only changes the first-time added coating agent to be the butyl titanate, and does not influence the dispersion of the particles in the diesel oil finally, which shows that the first-time added coating agent does not influence the external surface property of the particles, but influences the activity size of the final particles; compared with the example 1, the comparative example 4 has the defects that the final dispersion effect is poor because the related substance groups which enable the outermost layer of the particles to be coated with the tetraethoxysilane are added at the same time, the original surface property is changed, and the particles are not dispersed finally, so the weight of the effect of the respective amounts of different coating agents on the surface property of the final coating agent needs to be paid attention to during one-time addition, the amount and the proportion of the coating agent can be better controlled and mastered through adding the coating agents by times, but when a complex dispersion medium system is encountered, for example, a dispersion medium is a mixture of a plurality of types, the surface groups can be richer by adding the coating agent at one time to meet the complex liquid phase medium environment; compared with the example 1, the comparative example 5 replaces oleic acid of the coating agent added for the second time, has poor final dispersibility and cannot meet the requirement of the dispersion, which indicates that reasonable collocation needs to be carried out according to the property of the dispersion when a plurality of coating agents are adopted; compared with the example 1, the comparative example 6 changes the relative proportion of the two coating agents added for the second time, the total amount is unchanged, and the two coating agents can be finally dispersed, but the dispersing effect is general, which shows that the proportion of the coating agents influences the dispersing effect; compared with example 1, comparative example 7 reduces the amount of the coating agent added for the second time, so that the coating agent cannot be dispersed, and similarly comparative example 8 increases the addition amount of the coating agent added for the second time, so that the final dispersion effect is general, which shows that the amount of the coating agent is also important for obtaining a good dispersion result.

Examples 9 to 13

A transparent zinc oxide liquid dispersion was prepared by the procedure as described in example 1, except that the alkali concentrations in step 1) were 0.1mol/L, 0.3mol/L, 0.6mol/L, 1.2mol/L, and 2mol/L in this order. The effect of different alkali solution concentrations on the preparation results was tested and the results are shown in table 2.

Comparative examples 9 to 10

A transparent zinc oxide liquid dispersion was prepared by the procedure as described in example 1, except that the alkali solution concentration in step 1) was 0.08mol/L and 2.5mol/L in this order. The results are shown in Table 2.

TABLE 2 transparent zinc oxide liquid phase dispersions prepared with different alkali lye concentrations

Therefore, it can be seen from Table 2 that in the range of the alkali concentration of 0.1 to 2mol/L, the average particle size of the dispersion tends to decrease and then increase as the concentration of the material increases, and beyond this range, the dispersion cannot be finally formed.

Examples 14 to 17

Transparent zinc oxide liquid phase dispersions were prepared by the procedure as described in example 1, except that the lye feed rate in step 2) was 40ml/min, 100ml/min, 500ml/min, 800ml/min in this order. The effect of different lye concentrations on the preparation results (constant flow ratio of salt solution to lye) was tested and the results are shown in Table 3.

Comparative examples 11 to 12

A transparent zinc oxide liquid dispersion was prepared by the procedure as described in example 1, except that the alkali feed rate in step 2) was 20ml/min and 1000ml/min in this order. The results are shown in Table 3.

TABLE 3 transparent zinc oxide liquid phase dispersions prepared with different alkali lye feed flows

Therefore, it can be seen from Table 3 that in the range of the alkali solution feed rate of 40 to 800ml/min, the particle size of the dispersion tends to decrease first and then increase as the concentration of the material increases, and beyond this range, the dispersion cannot be formed finally.

Examples 18 to 21

A transparent zinc oxide liquid phase dispersion was prepared by the procedure as described in example 1, except that the rotating bed rotation speed in step 2) was 300rpm, 600rpm, 1400rpm, 2600rpm in this order. The effect of different rotating bed speeds on the preparation results was tested and the results are shown in table 4.

Comparative examples 13 to 15

Transparent zinc oxide liquid phase dispersions were prepared by the procedure as described in example 1, except that the rotating bed rotation speed in step 2) was 100rpm, 3600rpm, 5000rpm in this order. The results are shown in Table 4.

TABLE 4 transparent zinc oxide liquid phase dispersions prepared at different rotating speed of the rotating bed

Therefore, as can be seen from table 4, in the range of 300 to 5000rpm of the rotating bed, the particle size of the dispersion gradually decreases with the increase of the concentration of the material, and beyond 2600rpm, the particle size change is no longer obvious, and for energy saving, generally, the control is within 2600rpm, and less than 300rpm causes uneven mixing effect, resulting in failure to form stable dispersion.

Examples 22 to 24

Transparent zinc oxide liquid phase dispersions were prepared by the procedure as described in example 1, except that the reaction temperature in step 2) was 20 ℃, 40 ℃ and 85 ℃ in this order. The effect of different reaction temperatures on the preparation results was tested and the results are shown in table 4.

Comparative examples 16 to 18

Transparent zinc oxide liquid phase dispersions were prepared by the procedure as described in example 1, except that the reaction temperature in step 2) was 10 ℃, 90 ℃, 110 ℃ in this order. The results are shown in Table 4.

TABLE 5 transparent zinc oxide liquid phase dispersions prepared at different reaction temperatures

Therefore, it can be seen from Table 5 that, at a reaction temperature in the range of 20 to 85 ℃, the particle size of the dispersion tends to decrease and then increase as the reaction temperature increases, and beyond this range, the dispersion cannot be finally formed.

And (4) conclusion: the invention uses the supergravity technology to prepare the transparent zinc oxide liquid phase dispersoid, and obtains the dispersoid with the solid content of 70 percent. In addition, multiple coating agents are added in a divided manner, so that multiple coating layers are formed on the surfaces of the particles, and the dispersion of the dispersion is more stable. The transparent zinc oxide liquid phase dispersion obtained finally has high solid content, good stability and no sedimentation after standing for 12 months under the mutual matching and synergistic action among the introduction of the hypergravity technology, the improvement of the surface coating agent addition and the accurate setting of the operation steps and parameters.

It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention, and it will be obvious to those skilled in the art that other variations or modifications may be made on the basis of the above description, and all embodiments may not be exhaustive, and all obvious variations or modifications may be included within the scope of the present invention.

Claims

1. A method for preparing a transparent zinc oxide liquid phase dispersion is provided, wherein the one-dimensional size of zinc oxide is 3-10 nm, and the dispersion does not settle after standing for 12 months, and is characterized in that the method for preparing the zinc oxide liquid phase dispersion comprises the following steps:

4) precipitating, centrifuging and washing the standing modification solution, and dispersing into a liquid phase medium C to obtain a zinc oxide transparent liquid phase dispersion;

in step 4), the liquid phase medium C is selected from one or more of the following substances: diesel oil, naphtha, heavy oil, n-heptane, JP-10 aviation fuel oil, vacuum distillate oil, atmospheric residue and vacuum residue;

when the liquid phase medium C in the step 4) is diesel oil, the coating agent in the step 3) is added in the following mode: adding ethyl orthosilicate, and then adding gamma-methacryloxypropyl trimethoxysilane and oleic acid which are mixed in a mass ratio of 1: 1;

when the liquid phase medium C in the step 4) is heavy oil, the coating agent in the step 3) is added in a mode of: adding tetraethoxysilane, octadecylamine and oleic acid in a mass ratio of 2:5:5 at one time;

when the liquid phase medium C in the step 4) is vacuum distillate oil, the adding mode of the coating agent in the step 3) is as follows: firstly adding butyl titanate, and then adding mixed gamma-glycidoxypropyltrimethoxysilane and polyvinylpyrrolidone in a mass ratio of 1: 2;

when the liquid-phase medium C in the step 4) is JP-10 aviation fuel oil, the coating agent in the step 3) is added in the following mode: adding ethyl orthosilicate and then adding dodecyl trimethoxy silane;

when the liquid phase medium C in the step 4) is n-heptane, the coating agent in the step 3) is added in a mode of: firstly adding methyl aluminate and then adding n-octyl trimethoxy silane;

when the liquid phase medium C in the step 4) is atmospheric residue, the coating agent in the step 3) is added in the following mode: firstly, adding butyl borate and ethyl orthosilicate in a mass ratio of 1:1, and then adding n-octyltrimethoxysilane;

when the liquid phase medium C in the step 4) is vacuum residue, the coating agent in the step 3) is added in the following mode: firstly, adding gamma-aminopropyltriethoxysilane and octadecyltrimethoxysilane which are mixed in a mass ratio of 1: 3;

when the liquid phase medium C in the step 4) is naphtha, the coating agent in the step 3) is added in a mode of: directly adding oleic acid;

in the step 1), the concentration of the zinc salt is 0.05 mol/L-2 mol/L; the concentration of the alkali liquor is 0.1-2 mol/L;

in the step 2), the molar flow rate ratio of the salt solution and the alkali liquor introduced into the rotary packed bed is 0.2-3.5: 1; the feeding flow of the mixed salt solution into the rotary packed bed is 50 ml/min-1000 ml/min, and the alkali liquor is 40 ml/min-800 ml/min; the rotating speed of a rotor of the rotating bed is 300-2600 rpm;

in the step 2), the reaction temperature is 20-85 ℃;

in the step 3), the mass ratio of the added mass of the surface coating agent to the mass of the zinc oxide is 0.1-2: 1.

2. The method of preparing a transparent zinc oxide liquid dispersion according to claim 1, wherein in step 1) the zinc salt is selected from one or more of the following: zinc chloride, zinc bromide, zinc nitrate, zinc sulfate and zinc acetate; the salt of the doping element is selected from one or more of the following substances: aluminum sulfate, aluminum nitrate, aluminum acetate, aluminum isopropoxide, aluminum chloride, gallium nitrate, gallium sulfate, indium acetate, indium nitrate, indium chloride, tin chloride, and tin acetate; the base is selected from one or more of the following: lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonia monohydrate.

3. The method for preparing a transparent zinc oxide liquid phase dispersion according to claim 1, wherein in step 1), the liquid phase medium A is selected from one or more of the following substances: water, methanol, ethanol, ethylene glycol, isopropanol, butanol, benzyl alcohol, glycerol, diethyl ether, dimethyl ether, acetone, butanone and cyclohexanone; the liquid phase medium B is selected from one or more of the following substances: water, methanol, ethanol, ethylene glycol, isopropanol, glycerol, butanol, acetone, butanone, ethyl acetate, butyl acetate, toluene, xylene, dimethyl sulfoxide, tetrahydrofuran, n-hexane, cyclohexane.

4. The method for preparing transparent zinc oxide liquid-phase dispersion according to claim 1, wherein in step 2), the rotating bed reactor is a rotating packed bed hypergravity rotating bed reactor, a baffled hypergravity rotating bed reactor, a spiral channel hypergravity rotating bed reactor, a stator-rotor hypergravity rotating bed reactor or a rotating disc hypergravity rotating bed reactor.

5. A process for preparing a transparent zinc oxide liquid phase dispersion according to claim 1, characterized in that; in the step 3), the modification time is 5 min-6 h; the reaction temperature is 40-90 ℃; and standing for 2-48 h after the reaction is finished.

6. The method for preparing a transparent zinc oxide liquid-phase dispersion according to claim 5, wherein in step 3), when the surface coating agent is multiple, the surface coating agent is added in one mixing way or different surface coating agents are added at different times; the time interval for adding the materials in the times is 5 min-2 h.

7. The method for preparing a transparent zinc oxide liquid phase dispersion according to claim 1, wherein in step 4), the dispersion is ultrasonic dispersion.