Process for direct high-valued synthesis of biomass-based zwitterionic surfactant from pulping black liquor

Abstract

A preparation method of the biomass-based zwitterionic surfactant comprises the following steps: adjusting the pH value of pulping black liquor by using acid or alkali, centrifuging to take supernatant liquid, adding epoxy chloropropane, heating to a certain temperature, and reacting for a certain time. And then, adding an amine reagent to react for a certain time to obtain a brownish black biomass-based zwitterionic surfactant solution, and drying to obtain a biomass-based zwitterionic surfactant solid. According to the method, the biomass-based zwitterionic surfactant can be directly synthesized from the high-pollution pulping black liquor in a high-valued aqueous phase mode, the preparation process of the biomass-based zwitterionic surfactant is simple and low in energy consumption, the whole process is green and environmentally friendly, the black liquor does not need to be purified, organic reagents such as alcohols and formaldehyde do not need to be added, alkali recovery is not needed, and the method is suitable for industrial production. Commercialized production is easy to realize. The biomass-based zwitterionic surfactant can be applied to the fields of textile softeners, oil emulsifiers, bactericides, disinfectants and the like, and has a wide market prospect.

Description

Technical Field

[0001] The invention relates to the technical field of high-value utilization of biomass, and more specifically to a process for directly synthesizing biomass-based zwitterionic surfactants by high-value conversion of pulping black liquor. Background Art

[0002] Black liquor is a byproduct of alkaline pulping in the pulp production process. It is rich in lignin and is the largest natural source of aromatic hydrocarbons such as phenolic hydroxyl groups. The composition of pulping black liquor varies greatly between different mills, depending on the cooking process and the wood used, but the pollution caused by pulping black liquor is the same. Due to its high alkalinity and high COD content, pulping black liquor poses a serious threat to the environment and human health. How to convert pulping black liquor waste into useful products is of great significance. Using lignin-rich pulping black liquor to synthesize high-value-added products is the best way to reduce pollution.

[0003] Surfactants are known as "industrial MSG" and are one of the most widely used compounds in the world, with more than 6,000 species. They are particularly widely used in industrial production, food, washing and other industries. According to statistics, the global surfactant market revenue reached US$42.7 billion in 2020, and the total market demand reached 22.802 million tons. According to the dissociation properties of the polar groups in the surfactant molecules, they can be divided into four types: anionic surfactants, cationic surfactants, zwitterionic surfactants and nonionic surfactants.

[0004] Different from traditional anionic and cationic surfactants, amphoteric surfactants have many excellent properties due to their simultaneous presence of anions and cations, such as: low irritation, low toxicity; resistance to hard water and high concentration electrolytes; bactericidal and antibacterial properties; good wettability, good compatibility with other types of surfactant products, and synergistic effects. At present, there are not many types of amphoteric surfactants, and their high prices limit their wide application, but the unique advantages they show during use are sufficient to make up for their high prices in some occasions. In recent years, many researchers have focused on the synthesis and design of amphoteric surfactants, such as Chinese patent CN102631864A, which uses long-chain alkyl tertiary amines, epichlorohydrin and maleic anhydride to prepare amphoteric Gemini surfactants through salt formation, esterification and sulfonation processes. Chinese patent CN 103739826A uses diisocyanates and fatty amine polyoxyethylene ethers through polycondensation, chain extension and quaternization processes to prepare a polyurethane-type amphoteric surfactant. However, the raw materials used to synthesize zwitterions are all non-renewable and expensive petroleum derivatives. These zwitterions have poor degradation ability in the environment. With the discharge of waste residues and wastewater, they will enter the soil and water in large quantities, thereby polluting the ecological environment and ultimately endangering human life and health. With the increasing shortage of petroleum resources, surfactant products will gradually develop in the direction of green raw materials, environmentally friendly products, lower costs, and safer processing in the future. It will be of great significance to find more economical raw material substitutes and design more reasonable and environmentally friendly zwitterionic surfactant routes. Summary of the invention

[0005] To solve the above problems, the present invention provides a process for directly synthesizing biomass-based zwitterionic surfactants from pulping black liquor in high value, which can directly turn the highly polluting pulping black liquor discharged in the papermaking industry into treasure, and synthesize renewable and easily degradable biomass-based zwitterionic surfactants in high value in the aqueous phase; the whole process is green and environmentally friendly, and there is no need to purify the black liquor, add organic reagents such as alcohols and formaldehyde, and no need for alkali recovery.

[0006] The present invention specifically adopts the following technical solutions:

[0007] A process for directly synthesizing biomass-based zwitterionic surfactants from pulping black liquor in high value, comprising the following steps:

[0008] Take an appropriate amount of papermaking black liquor, adjust the pH of the pulping black liquor to a certain range with acid or alkali, centrifuge to take the supernatant, add an appropriate amount of epichlorohydrin, heat to a certain temperature and react for a certain time. Then add an appropriate amount of amine reagent to react for a certain time to obtain a brown-black biomass-based zwitterionic surfactant solution, and dry to obtain a biomass-based zwitterionic surfactant solid.

[0009] Furthermore, the pH of the pulping black liquor is adjusted to 8-13 with acid or alkali.

[0010] Furthermore, the amount of epichlorohydrin added is 1.0-10.0 times the hydroxyl group contained in the lignin in the papermaking black liquor, based on the molar ratio.

[0011] Furthermore, the reaction temperature is 40-100° C., and the reaction time before adding the amine reagent is 0-300 min.

[0012] Furthermore, the amount of the amine reagent added is 1.0-10.0 times the hydroxyl group contained in the lignin in the papermaking black liquor, based on the molar ratio.

[0013] Furthermore, the reaction time after adding the amine reagent is 10-300 minutes.

[0014] Furthermore, the brown-black solution obtained by the reaction is a biomass-based zwitterionic surfactant solution, and after drying, a biomass-based zwitterionic surfactant solid is obtained.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) The present invention can directly convert the highly polluting pulping black liquor discharged from the papermaking industry into a biomass-based zwitterionic surfactant with high value. The entire process is green and environmentally friendly, and there is no need to purify the black liquor, add organic reagents such as alcohols and formaldehyde, or recover alkali.

[0017] (2) The method of synthesizing biomass-based zwitterionic surfactants of the present invention is in an aqueous system rather than an organic system, and the production cost is low; the raw materials for synthesizing zwitterionic surfactants are renewable and easily degradable, which effectively reduces the consumption of fossil energy and reduces the possibility of ecological environmental pollution and harm to human life and health.

[0018] (3) The biomass-based zwitterionic surfactant synthesized in the present invention can be used in a variety of scenarios by flexibly adjusting the amount of amine added. When the amine content is increased, it can be mainly used as a curing agent for epoxy emulsified asphalt, and when the amine content is reduced, it can be mainly used as a surfactant.

[0019] (4) The present invention transforms highly polluting pulping black liquor into valuable materials to produce high-value biomass-based zwitterionic surfactants, which has simple process, low energy consumption and short production cycle, and provides a basis for the large-scale production of biomass-based zwitterionic surfactants with renewable and easily degradable raw materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The process route for directly synthesizing biomass-based zwitterionic surfactants from pulping black liquor in the present invention is as follows;

[0021] Figure 2 These are pictures of the solubility of the biomass-based zwitterionic surfactant prepared in Example 1 in a acidic, b neutral, and c alkaline solutions. DETAILED DESCRIPTION

[0022] The present invention is described in detail below in conjunction with the accompanying drawings and specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the following examples are conventional means well known to those skilled in the art, and the materials, reagents, etc. used in the following examples, unless otherwise specified, can be obtained from commercial sources.

[0023] Example 1

[0024] 50 mL of pulping black liquor was adjusted to pH 11, 0.5 mL of epichlorohydrin was added, and the temperature was raised to 60°C for reaction for 30 min. Then, 0.9 g of trimethylamine hydrochloride was added for reaction for 30 min to obtain a brown-black biomass-based zwitterionic surfactant solution, which was dried to obtain a biomass-based zwitterionic surfactant solid.

[0025] Example 2

[0026] 50 mL of pulping black liquor was adjusted to pH 12, 0.7 mL of epichlorohydrin was added, and the temperature was raised to 50°C for reaction for 10 min. Then, 0.7 mL of diethyltriamine was added for reaction for 30 min to obtain a brown-black biomass-based zwitterionic surfactant solution, which was dried to obtain a biomass-based zwitterionic surfactant solid.

[0027] Example 3

[0028] 50 mL of pulping black liquor was adjusted to pH 10, 0.5 mL of epichlorohydrin was added, and the temperature was raised to 80°C for 20 min. Then, 0.7 g of trimethylamine hydrochloride was added for 1 h to obtain a brown-black biomass-based zwitterionic surfactant solution, which was dried to obtain a biomass-based zwitterionic surfactant solid.

[0029] Example 4

[0030] 50 mL of pulping black liquor was adjusted to pH 11, 0.9 mL of epichlorohydrin was added, and the temperature was raised to 60°C for reaction for 30 min. Then, 0.9 mL of diethyltriamine was added for reaction for 2 h to obtain a brown-black biomass-based zwitterionic surfactant solution, which was dried to obtain a biomass-based zwitterionic surfactant solid.

[0031] Example 5

[0032] 50 mL of pulping black liquor was adjusted to pH 12, 1 mL of epichlorohydrin was added, and the temperature was raised to 70°C for reaction for 10 min. Then, 1 mL of diethyltriamine was added for reaction for 2 h to obtain a brown-black biomass-based zwitterionic surfactant solution, which was dried to obtain a biomass-based zwitterionic surfactant solid.

[0033] As shown in Table 1, the surface tension (10 mg / L) of the bio-based zwitterionic surfactants prepared in Examples 1-5 is less than that of deionized water under both acidic and alkaline conditions, which indicates that bio-based zwitterionic surfactants with good surface activity can also be obtained from pulping black liquor in an aqueous phase without aldehyde. Figure 2 The results show that the prepared bio-based surfactant can be dissolved under both acidic and alkaline conditions, and the partial dissolution under neutral conditions also proves that the prepared surfactant is a bio-based zwitterionic surfactant.

[0034] It should be noted that when the claims of the present invention involve numerical ranges, it should be understood that the two endpoints of each numerical range and any numerical value between the two endpoints can be selected. In order to avoid redundancy, the present invention describes a preferred embodiment.

[0035] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0036] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

[0037] Table 1 Surface tension of samples (10 mg / L)

[0038] sample Acid surface tension (mN / m) Alkaline surface tension (mN / m) Example 1 50.56 61.76 Example 2 49.84 59.77 Example 3 48.11 55.57 Example 4 45.75 53.64 Example 5 47.95 55.07

[0039] *The surface tension of deionized water is 72.81 mN / m.

Claims

1. A process for directly synthesizing biomass-based zwitterionic surfactants from pulping black liquor, characterized in that: The following steps are involved: Take an appropriate amount of pulping black liquor, adjust the pH of the pulping black liquor to a certain range with acid or alkali, centrifuge to take the supernatant, add an appropriate amount of epichlorohydrin, heat to a certain temperature and react for a certain time. Then add an appropriate amount of amine reagent to react for a certain time to obtain a brown-black biomass-based zwitterionic surfactant solution, and dry to obtain a biomass-based zwitterionic surfactant solid.

2. According to claim 1, a process for directly synthesizing biomass-based zwitterionic surfactants from pulping black liquor, characterized in that: The pH of the pulping black liquor is adjusted to 8-13 with acid or alkali. The acid can be an inorganic acid such as hydrochloric acid, phosphoric acid, sulfuric acid, or an organic acid such as formic acid, acetic acid, or a combination of several of them.

3. The process for directly synthesizing biomass-based zwitterionic surfactants from pulping black liquor according to claim 1, characterized in that: The amount of epichlorohydrin added is 1.0-10.0 times the hydroxyl group contained in the lignin in the papermaking by-product black liquor, based on the molar ratio.

4. The process for directly synthesizing biomass-based zwitterionic surfactants from pulping black liquor according to claim 1, characterized in that: The reaction temperature is 40-100°C, and the reaction time before adding the amine reagent is 0-300 minutes.

5. The process for directly synthesizing biomass-based zwitterionic surfactants from pulping black liquor according to claim 1, characterized in that: The amount of the amine reagent added is 1.0-10.0 times the hydroxyl group contained in the lignin in the papermaking black liquor, based on the molar ratio; the amine reagent can be one or a combination of trimethylamine, diethyltriamine, trimethylamine hydrochloride, etc.

6. The process for directly synthesizing biomass-based zwitterionic surfactants from pulping black liquor according to claim 1, characterized in that: The reaction time after adding the amine reagent is 10-300 minutes.

7. The process for directly synthesizing biomass-based zwitterionic surfactants from pulping black liquor according to claim 1, characterized in that: The brown-black solution obtained by the reaction is a biomass-based zwitterionic surfactant solution, and the biomass-based zwitterionic surfactant solid is obtained after drying.

8. The use of the biomass-based zwitterionic surfactant according to claims 1-7, characterized in that: The biomass-based zwitterionic surfactant can be applied to the fields of textile softeners, antistatic agents, oil emulsifiers, bactericides and disinfectants.

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