阅读说明：本技术 一种磺化椰壳活性炭固体酸催化剂的制备方法 (Preparation method of sulfonated coconut shell activated carbon solid acid catalyst ) 是由 陈俊华 杨建新 陈骞骞 杨嫒 王璇 巢馨丹 于 2018-06-13 设计创作，主要内容包括：一种磺化椰壳活性炭固体酸催化剂的制备方法,本发明公开了一类新的椰壳生物质能源碳基固体酸催化剂的制备方法,及该材料作为催化剂的应用。此类催化剂在酯化类物质的合成中,有着高效的催化活性,对脂肪酸与脂肪醇、脂肪酸与芳香醇的酯化有良好的催化效果。在酮类的羰基保护,酮类缩合等方面同样有着高效的催化活性。本发明具有原料所使用的生物质能源材料有着来源广泛、廉价、可再生、来源广泛等特点,及使用时无工业废水产生,过程绿色化且对设备无腐蚀性等特点使其存在代替传统均相酸催化剂的潜力。通过控制炭化温度实现对炭基体比表面积、孔径大小、孔道类型的控制,使该催化剂的功能性实现可控性。该催化剂在应用时体现出优于其它类常见固体酸催化剂的催化性能,且其在重复性和可再生性。(The invention discloses a preparation method of a sulfonated coconut shell activated carbon solid acid catalyst, and discloses a preparation method of a novel coconut shell biomass energy carbon-based solid acid catalyst and application of the material as a catalyst. The catalyst has high-efficiency catalytic activity in the synthesis of esterified substances, and has good catalytic effect on the esterification of fatty acid and fatty alcohol and fatty acid and aromatic alcohol. The catalyst has high catalytic activity in the aspects of carbonyl protection of ketones, condensation of ketones and the like. The invention has the characteristics of wide, cheap, renewable and wide sources of biomass energy materials used as raw materials, no industrial wastewater generation during use, green process, no corrosion to equipment and the like, so that the biomass energy materials have the potential of replacing the traditional homogeneous acid catalyst. The specific surface area, the pore size and the pore canal type of the carbon matrix are controlled by controlling the carbonization temperature, so that the controllability of the functionality of the catalyst is realized. The catalyst shows better catalytic performance than other common solid acid catalysts when in use, and has repeatability and reproducibility.)

1. A preparation method of a catalyst of coconut shell activated carbon loaded with acid functional groups comprises the following process steps:

firstly, preparing a coconut shell raw material: taking waste coconut shells, removing peel layers of the coconut shells, leaving fiber layers, cutting the fiber layers, drying in a drying box, and crushing by a crusher to obtain coconut shell powder and a coconut shell fine fiber raw material;

secondly, activating raw materials, namely preparing the coconut shell fiber raw materials and a KOH activating agent into a solvent according to the mass ratio of 1:1 ~ 3:15, uniformly soaking, and drying to obtain a mixture sample;

③ carbonizing: adding the carbonized precursor obtained in the step II into N₂Carbonizing at 350 deg.C of ~ 750 deg.C and 750 deg.C for 1 ~ 3h, and cooling to room temperature;

fourthly, washing with water: mashing the carbonized product by using a mortar, adding a proper amount of deionized water, stirring in an oil bath at 80 ℃ for 2 hours, fully washing, washing and filtering by using the deionized water at 80 ℃ until the filtrate is neutral, and drying in an oven at 105 ℃ to obtain coconut shell activated carbon;

fifthly, sulfonation reaction, namely mixing the coconut shell activated carbon with a sulfonating agent in a mass ratio of 1:10 ~ 40, magnetically heating and stirring for 1 ~ 4 hours at 80 ℃, cooling to room temperature, diluting, washing with hot water at 80 ℃, and performing suction filtration until filtrate is free of SO₄ ^2-And drying in a drying box at 105 ℃ to obtain the coconut shell carbon-based solid acid.

2. The method for preparing the sulfonated coconut charcoal based solid acid catalyst according to claim 1, wherein the coconut activated carbon is subjected to a supporting reaction with a sulfonating agent.

3. The method for preparing the sulfonated coconut carbon-based solid acid catalyst according to claim 2, wherein the sulfonating agent in the above step is but not limited to concentrated sulfuric acid, oleum, sulfur trioxide.

4. The method for preparing the sulfonated coconut charcoal based solid acid catalyst according to claim 2, wherein the adding mass ratio of the coconut activated carbon to the activating agent is 1:10 ~ 40.

5. The method for preparing the sulfonated coconut charcoal based solid acid catalyst according to claim 2, wherein the supported reaction time is 1 ~ 4 h.

6. The method for preparing coconut shell activated carbon according to claim 2, wherein the activating agent is selected from KOH and ZnCl₂One kind of (1).

7. The method for preparing coconut shell activated carbon according to claim 2, wherein the ratio of the activating agent to the coconut shell powder raw material is 1:1 ~ 3.

8. The method for preparing coconut shell activated carbon according to claim 2, wherein the carbonization temperature is 350 ℃ ~ 750 ℃.

9. The preparation method of coconut shell activated carbon according to claim 2, characterized in that the carbonization heat preservation time is 1 ~ 3 h.

Technical Field

The invention relates to a preparation method of coconut shell activated carbon and a preparation method for preparing a supported sulfonated coconut shell carbon solid acid catalyst by using the coconut shell activated carbon. The catalyst can be used for catalyzing esterification synthesis of fatty acid and fatty alcohol, condensation reaction of aldehyde ketone and alcohol, and the like.

Background

The solid acid catalyst is used as a green catalyst, and the green catalyst is a necessary way for industrial production development when the environmental problem is severe; the solid acid catalyst gradually receives wide attention due to the characteristics of high activity, strong performance, separability, reusability, synthesis, greenness in use and the like. Common solid acids such as molecular sieves, strong-acid cation exchange resins, heteropoly acids and the like have the defects of limited catalytic performance, complex synthetic steps, high price and the like, and limit the function of the solid acids in industrial production.

The biomass energy is cheap renewable green energy with abundant reserves and wide sources, and is widely applied to the field of energy power generation; the biological adsorbent can replace coal as fuel in industrial production; biomass is converted into value-added chemicals and fuels, etc. The utilization of a large number of biomass energy sources, such as: cellulose, lignin, bamboo powder, etc. have been developed and utilized as carbon matrices for preparing solid acid catalysts. The invention utilizes the principle of group loading to combine biomass energy with acidic group loading, and prepares a novel biomass active carbon solid acid catalyst.

Disclosure of Invention

The invention aims to prepare functional activated carbon with ordered structure and rich pore channels by using biomass energy, solve the problems of complex and expensive solid acid synthesis method, single catalytic performance and the like by using the activated carbon, and prepare a supported coconut shell carbon-based solid acid catalyst with strong acid catalytic performance, which has the characteristics of wide source, low price, greenness, renewability and the like of synthesis raw materials.

In order to realize the invention, the embodiment of the invention is as follows: firstly preparing biomass energy active carbon, and preparing a catalyst by using a method of loading functional groups.

1) Preparing a coconut shell biomass raw material: taking waste fresh coconut shells, removing surface peel layers and inner layer pulp layers, leaving intermediate fiber layers, shearing, crushing and drying for later use. Crushing the cut fiber layer in a crusher to obtain a mixture of coconut shell fiber powder and fine fibers, and drying the mixture to obtain the raw material.

2) And (3) activating, namely fully and uniformly soaking the prepared coconut shell biomass raw material, an activating agent and water according to the mass ratio of 1:1 ~ 3:15 for 24 hours, stirring once every 8 hours, and drying to obtain a carbonized precursor sample.

3) And (3) carbonizing, namely putting the dried sample into a small porcelain boat, carbonizing at the temperature of 350 ℃ and ~ 750 ℃ in a tube furnace in the nitrogen atmosphere, preserving heat for 1 ~ 3h, and naturally cooling to room temperature.

4) And (3) water washing, namely adding a large amount of deionized water into the carbonized product, fully mixing, fully stirring for 1 ~ 3 hours in an oil bath at the temperature of 80 ℃ to ensure that the activating agent is fully peeled and dissolved, fully washing and filtering by using the deionized water at the temperature of 80 ℃ until the filtrate is neutral, and drying in a drying oven at the temperature of 105 ℃ for later use to obtain the coconut shell biomass activated carbon.

5) Sulfonation reaction, mixing coconut shell biomass activated carbon and a sulfonating agent according to the mass ratio of 1:10 ~ 40, magnetically stirring the mixture in an oil bath at the temperature of 80 ~ 140 ℃ for 1 ~ 4h, diluting the mixture with deionized water, fully washing the mixture with the deionized water, and performing suction filtration until the filtrate is free of SO₄ ^2-And detecting, and drying the product in a drying oven at 105 ℃ to obtain the sulfonated coconut shell carbon-based solid acid catalyst.

The coconut shell biomass raw material is a mixture of coconut shell powder and coconut shell fibers which are mixed according to any proportion.

The ratio of the coconut shell fiber raw material to the activating agent to the water is 1:10 ~ 40: 15.

The above carbonization temperature range was 350 ℃ ~ 750 ℃.

The carbonization heat preservation time is 1 ~ 3 h.

The sulfonating agent in the sulfonation step is one of concentrated sulfuric acid, fuming sulfuric acid and sulfur trioxide.

The mass ratio of the biomass activated carbon to the sulfonating agent is 1:10 ~ 40.

The sulfonation time was 1 ~ 4 h.

The invention has the characteristics of innovation point and technical scheme.

1. The prepared functional activated carbon with multiple pore passages and controllable pore diameters has a more specific, ordered and controllable mesoporous structure compared with the commercially available activated carbon, so that the functions of the activated carbon are better and more specific.

2. The prepared coconut shell biomass activated carbon is used for sulfonating and loading to synthesize solid acid, and compared with homogeneous catalysts used in the industrial traditional acid catalysis production, such as sulfuric acid, phosphoric acid and the like, the solid acid has the advantages of high catalytic performance, separability, reusability, greenness in production, no pollution of waste liquid generation of products and the like.

3. The advantages of reproducibility of biomass energy, wide source of raw materials, low cost of raw materials, maximum utilization of resources and the like which accord with the sustainable development concept are utilized, and the biomass carbon-based solid acid synthesized by combining with the functional coconut shell biomass activated carbon has the advantages of the biomass energy and the heterogeneous solid acid, and overcomes the defects of complex synthesis process, high cost, easy inactivation and the like of the solid acid in use.

Drawings

FIG. 1 is a schematic diagram of the synthesis process of coconut shell activated carbon prepared in example 1.

FIG. 2 is an XRD pattern of the coconut shell fiber raw material and coconut shell activated carbon prepared in example 1, which demonstrates that carbonization causes the structure of the material to change.

FIG. 3 is FT-IR spectra of the coconut shell activated carbon prepared in example 1 and sulfonated coconut shell activated carbon, demonstrating that sulfonation successfully supports sulfonic acid groups on a coconut shell activated carbon matrix.

FIG. 4 is a TGA analysis of the sulfonated coconut shell carbon prepared in example 1, showing the applicable temperature range of the catalyst.

FIG. 5 is an SEM image of the sulfonated coconut carbon prepared in example 1, showing the microstructure and channel structure of the catalyst.

FIG. 6 is a plot of acid conversion over time for catalysts prepared in example 2 ~ 4, in which catalysts synthesized with different raw material and activator mass ratios catalyze the esterification of acetic acid with n-butanol.

FIG. 7 is a plot of acid conversion over time for the esterification of acetic acid with n-butanol catalyzed by prepared catalysts synthesized at different carbonization temperatures in example 5 ~ 8.

FIG. 8 is a graph of acid conversion versus time for the esterification of acetic acid with n-butanol catalyzed by catalysts prepared at different incubation times for carbonization as in example 9 ~ 12.

FIG. 9 is a graph of the acid conversion over time for the esterification of acetic acid with n-butanol catalyzed by catalysts prepared from different coconut shell activated carbon to sulfonating agent dosage ratios in example 13 ~ 15.

FIG. 10 is a plot of acid conversion versus time for the esterification of acetic acid with n-butanol catalyzed by catalysts prepared at different sulfonation times in example 16 ~ 18.

FIG. 11 is a plot of acid conversion over time for other types of esterification reactions catalyzed by catalysts prepared under the optimum conditions of example 20 ~ 24.

FIG. 12 is a graph of the conversion of cyclohexanone to ethylene glycol condensed ketone over time using the catalyst prepared under the optimum conditions in example 25 ~ 26.

FIG. 13 is a plot of the conversion of cyclohexanone to ethanol condensed ketone over time using the catalyst prepared under the optimum conditions in example 25 ~ 26, and the invention is further illustrated by the specific examples below.

Detailed Description

Example 1 preparation of coconut shell biomass feedstock: taking waste coconut shells, removing surface peel layers and inner layer pulp layers, leaving intermediate fiber layers, shearing, crushing and drying for later use. Crushing the cut fiber layer in a crusher to obtain a mixture of coconut shell fiber powder and fine fibers, and drying the mixture to obtain the raw material.

Activation of raw materials: weighing 3g of the coconut shell biomass raw material prepared in the above manner in a watch glass, and adding 3g of activating agent KOH and 45 ml of water according to a mass ratio of 1: 1: 15, soaking for 24 hours, and drying for later use.

Carbonizing the raw materials: taking out the dried sample, breaking the dried sample into blocks, placing the blocks into a small porcelain boat, carbonizing the blocks in a tube furnace at 450 ℃ at the heating rate of 10 ℃/min in the nitrogen atmosphere, preserving the heat for 2h, and naturally cooling the blocks to room temperature.

Washing a product with water: taking out the carbonized product, smashing the carbonized product by using a mortar until no obvious block exists, adding a large amount of deionized water, fully mixing, and fully stirring for 2 hours in an oil bath at the temperature of 80 ℃ to ensure that the activating agent is fully fallen and dissolved. Then fully washing and filtering the mixture by using deionized water at the temperature of 80 ℃ until the filtrate is neutral, and drying the filtrate in a drying box at the temperature of 105 ℃ for later use to obtain the coconut shell biomass activated carbon.

And (3) sulfonation reaction: taking coconut shell biomass activated carbon and a sulfonating agent according to the mass ratio of 1: 20, magnetically stirring in an oil bath at 80 ℃ for 2 hours, diluting the mixture with deionized water, fully washing with deionized water, and filtering until the filtrate is free of SO₄ ^2-And detecting, and drying the product in a drying oven at 105 ℃ to obtain the sulfonated coconut shell carbon-based solid acid catalyst.

Example 2 ~ 4 the mass ratio of starting material to activator to water was varied over the process steps of example 1.

Example 5 ~ 8 on the process step of example 1, the carbonization temperature was varied at the carbonization step.

Example 9 ~ 12 the time for the carbonation soak was varied over the process steps of example 1.

Example 13 ~ 15 the ratio of the mass of coconut shell activated carbon to the mass of sulfonating agent was varied over the process steps of example 1.

Example 16 ~ 18 the sulfonation time was varied over the process steps of example 1.

The sulfonated coconut shell biomass solid acid prepared by the 18 groups of examples obtained above is used for catalyzing the esterification reaction of acetic acid and n-butyl alcohol, and the catalytic effect and the influence of various preparation synthesis factors on the performance of the catalyst are researched.

Example 19 catalytic esterification experimental procedure: in a 50ml round bottom flask, 1.14 ml (0.02 mol) of acetic acid and 18.5ml of n-butanol (0.2 mol) were added to make the acid to alcohol ratio 1:10, heated in an oil bath until the system just boiled (120 ℃ C.), and 0.05g of catalyst was added to condense under reflux to start the reaction.

Sampling and detecting: suspending the reaction in ice water bath respectively at 10min, 20min, 30min, 45min, 1h, 2h, 3h, 4h and 5h, taking 50 mu L of reaction solution by using a pipette, adding 1mL of absolute ethyl alcohol for dilution, filtering by using a needle filter plug, detecting by using a gas chromatograph, and calculating the real-time reaction conversion rate.

Analysis of data by integrated analysis of the data we have used as a point of investigation the conversion at 2h of the esterification of acetic acid with n-butanol over the catalyst prepared in example 1 ~ 18, the data of which are given in the following table.

By carrying out data analysis on the results of the same esterification reaction catalyzed by the catalyst synthesized in the embodiment 1 ~ 18 under the same reaction method, the condition parameters of the most efficient catalyst synthesis are screened out, the synthesis condition with the best acid catalysis performance is found, and the catalyst prepared by utilizing the condition is used for carrying out other esterification reactions.

Example 20 ~ 24 other esterification reactions were carried out in the same manner as in example 19 except that 0.01mol of the acid propionic acid, butyric acid, valeric acid or acetic acid and 0.1mol of the alcohol n-butanol, ethanol or benzyl alcohol were used and the conversion was carried out for 2 hours.