Background
China is a country rich in rosin resources, but compared with developed countries, deep processing yield and quality of the cheap rosin/turpentine resources have great difference, and most of the resources are exported in a raw material form. Therefore, the method has very important strategic significance on the deep research of the production process of the downstream products with high added values.
Wherein, the main component alpha-pinene of turpentine can be selectively catalyzed and hydrogenated to obtain cis-pinane product which can be used as important chemical raw material for synthesizing fine chemicals such as drugs, spices and the like. The alpha-pinene hydrogenation process promoted by Pd/C, Raney-Ni and some other metal supported catalysts which are commonly used in industry has the problems of higher requirements on reaction temperature and pressure, lower product selectivity, easy coking of the catalysts and the like. People continuously seek a high-selectivity heterogeneous catalytic system (CN 1191857A; CN 1262263A; CN 102125864A; CN 101884925A; US 4018842; US4310714) by methods such as modification, but the defects of harsh catalytic reaction conditions, serious environmental pollution in the preparation or use process of the catalyst, poor reusability of the catalyst and the like are not effectively solved. The use of homogeneous catalysts of Rh, Ir and other metal complexes has the problems of easy loss and product pollution during catalyst separation (CN 104003831A; J.organometal.chem.,1991,405(3): 383-391; Aust.J.chem.,1992,45(1): 143-149). With the excellent activity of the metal nanoparticles in the organic redox reaction, the application of the metal nanoparticles in the alpha-pinene hydrogenation process is also regarded as important (RSC adv, 2015,5: 89552-89558; Catl.Lett., 2016,146(3): 580-586; appl.Surf.Sci.,2018,453: 271-279; Rsc adv, 2016,6(60): 54806-54811; mol.Cat., 2018, 1): 62-69; Rsc adv, 2017, 81):51452-51459), and good catalytic effect is obtained. However, the preparation and use of the metal nanoparticle catalyst inevitably involve the use of various chemical reagents as raw materials, reducing agents or stabilizers, and the preparation process of the catalyst is complicated. If the method can realize the preparation of the catalyst and the high-efficiency catalytic reaction under the environment-friendly condition by completely using cheap natural renewable resources as raw materials or media, and the catalyst can be simply recycled and reused without polluting products, a green new method is expected to be provided for the utilization of alpha-pinene resources and the preparation of cis-pinane products.
Lignin is the second most abundant natural polymer in nature and has aromatic ring backbone structures and various functional groups that other biomass resources do not possess. Besides separating and obtaining lignin from agricultural and forestry wastes and cellulose, hemicellulose and the like, the commercial lignin is used as a byproduct of a paper industry, so that the yield is high, and the high-value utilization of the commercial lignin is beneficial to environmental and economic development. Lignosulfonate derived from papermaking black liquor has attracted attention in recent years because of good water solubility, and is used for preparing and stabilizing metal nanoparticles such as silver, gold and the like in a water phase or an organic phase, and is used for C-C coupling reaction, electrocatalysis process and the like (int.J.biol.Macromol.,2016,82: 856-862; mater.Lett.,2015,159: 451-454; colloid.surface.B,2013,105: 335-341; Green chem.,2011,13: 283-287). However, the application of the transition metal nanoparticle aqueous phase system reduced and stabilized by lignin in the catalytic hydrogenation preparation of fine chemicals such as pinane and the like has not been reported in domestic and foreign documents so far.
Disclosure of Invention
The method utilizes the synergistic effect of different functional groups in the sodium lignosulfonate structure, reduces chloroplatinic acid in a water phase under the condition of no additional reducing agent, stabilizer and organic solvent, and simultaneously stabilizes the generated platinum nanoparticles to obtain a water-phase hydrogenation catalytic system, catalyzes the alpha-pinene hydrogenation reaction in a batch reactor, and efficiently prepares the cis-pinane.
The invention aims to solve the problems that the preparation and stabilization processes of active components of a metal nanoparticle catalyst and the catalytic reaction process of the active components are difficult to avoid the use of chemical reducing agents, surfactants, organic solvents and the like in the prior art of the alpha-pinene catalytic hydrogenation process, thereby providing an environment-friendly new method for efficiently preparing cis-pinane by utilizing the structural characteristics of lignin, reducing and stabilizing metal platinum nanoparticles in a water phase in one pot and directly adopting the hydrosol system to catalyze the alpha-pinene hydrogenation reaction.
The technical scheme of the invention is as follows:
adding sodium lignosulfonate and H in a certain proportion into a stainless steel reaction kettle with a polytetrafluoroethylene lining2PtCl6·6H2O and ultrapure water are fully dissolved by stirring at room temperature, and thenHeating to 80 ℃, reacting for 3h under magnetic stirring at 400rpm, and cooling to obtain a black opaque water-phase Pt metal nanoparticle stable catalytic system.
In the prepared Pt metal nano particle water phase catalysis system, a certain amount of alpha-pinene is directly added, the kettle is sealed, hydrogen is used for replacing air, the hydrogen pressure of 1.0MPa is kept, and hydrogenation reaction is carried out under the magnetic stirring of 70 ℃ and 400 rpm. After the reaction is finished, the upper product phase is removed, and the water phase catalyst system is directly reused.
Compared with the prior art, the method for preparing the cis-pinane by catalyzing the hydrogenation of the alpha-pinene by the metal platinum nano particles through aqueous phase reduction and stabilization of the lignin, which is provided by the invention, has the following characteristics:
(1) the invention provides a method for directly catalyzing alpha-pinene hydrogenation reaction in a water phase by using waste biomass derivatization product lignosulfonate as a reducing agent and a stabilizing agent of a metal active catalytic component, which is simple, convenient, feasible, clean and cheap;
(2) the method provided by the invention does not need any organic solvent or other chemical reagents in the preparation stage and the catalytic hydrogenation reaction stage of the catalyst, and has mild reaction conditions and environmental friendliness;
(3) the method for catalyzing alpha-pinene hydrogenation provided by the invention has very high catalytic activity and cis-pinane product selectivity, and the water phase catalyst system can be directly reused and has stable catalytic performance.
Detailed description of the invention
The process of the present invention is further illustrated, but is not intended to be limited, by the following examples.
Example 1 preparation of Pt Metal nanoparticle catalyst A stabilized by sodium Lignosulfonate reduction
60.0mg of sodium lignosulfonate (96%, molecular weight: 534.51), 0.1mmol of H, which has been vacuum dried for 24 hours, are added to a stainless steel reaction kettle with a polytetrafluoroethylene lining2PtCl6·6H2O and 6mL of ultrapure water are fully dissolved by stirring at room temperature, heated to 80 ℃, stirred at 400rpm for reaction for 3 hours and then cooled.
Figure 1 shows that after the sodium lignosulfonate is reduced and stabilized for 3 hours, the ultraviolet characteristic absorption peak of chloroplatinic acid disappears; figure 2 shows that zero-valent platinum is generated after sodium lignosulfonate is reduced and stabilized for 3 hours.
Example 2 preparation of Pt Metal nanoparticle catalyst B stabilized by sodium Lignosulfonate reduction
100.0mg of sodium lignosulfonate (96%, molecular weight: 534.51), which has been vacuum dried for 24 hours, 0.1mmol of H, are added to a stainless steel reaction kettle with a polytetrafluoroethylene lining2PtCl6·6H2O and 6mL of ultrapure water are fully dissolved by stirring at room temperature, heated to 80 ℃, stirred at 400rpm for reaction for 3 hours and then cooled.
Example 3 preparation of Pt Metal nanoparticle catalyst C stabilized by sodium Lignosulfonate reduction
60.0mg of sodium lignosulfonate (96%, molecular weight: 534.51), 0.1mmol of H, which has been vacuum dried for 24 hours, are added to a stainless steel reaction kettle with a polytetrafluoroethylene lining2PtCl6·6H2O and 12mL of ultrapure water are fully dissolved by stirring at room temperature, heated to 80 ℃, stirred at 400rpm for reaction for 3 hours and then cooled.
[ example 4 ] A Pt metal nanoparticle catalyst A with stable sodium lignosulfonate reduction for catalyzing alpha-pinene hydrogenation reaction
40mmol of alpha-pinene was added to a stainless steel reactor containing the sodium lignosulfonate reduction-stable platinum nanoparticle catalyst A prepared in example 1. The air in the reaction vessel was replaced with hydrogen five times, and then 1.0MPa hydrogen was charged and reacted at 70 ℃ for 1.5 hours with magnetic stirring at 400 rpm. After the reaction was completed, the upper product phase was collected and quantitatively analyzed by gas chromatography.
[ example 5 ] sodium lignosulfonate reduction-stable Pt metal nanoparticle catalyst B catalyzes alpha-pinene hydrogenation reaction
40mmol of alpha-pinene was added to a stainless steel reactor containing the sodium lignosulfonate reduction-stable platinum nanoparticle catalyst B prepared in example 2. The air in the reaction vessel was replaced with hydrogen five times, and then 1.0MPa hydrogen was charged and reacted at 70 ℃ for 1.5 hours with magnetic stirring at 400 rpm. After the reaction was completed, the upper product phase was collected and quantitatively analyzed by gas chromatography.
[ example 6 ] sodium lignosulfonate reduction-stable Pt metal nanoparticle catalyst C catalyzes alpha-pinene hydrogenation reaction
40mmol of alpha-pinene was added to a stainless steel reactor charged with the sodium lignosulfonate reduction-stable platinum nanoparticle catalyst C prepared in example 3. The air in the reaction vessel was replaced with hydrogen five times, and then 1.0MPa hydrogen was charged and reacted at 70 ℃ for 1.5 hours with magnetic stirring at 400 rpm. After the reaction was completed, the upper product phase was collected and quantitatively analyzed by gas chromatography.
[ example 7 ] optimization of hydrogenation reaction of alpha-pinene catalyzed by Pt metal nanoparticle catalyst A with stable reduction of sodium lignosulfonate
40mmol of alpha-pinene was added to a stainless steel reactor containing the sodium lignosulfonate reduction-stable platinum nanoparticle catalyst A prepared in example 1. The air in the reaction vessel was replaced with hydrogen five times, and then 1.0MPa hydrogen was charged and reacted at 70 ℃ for 2 hours with magnetic stirring at 400 rpm. After the reaction was completed, the upper product phase was collected and quantitatively analyzed by gas chromatography.
TABLE 1 sodium lignosulfonate reduction-stabilized Pt metal nanoparticles catalyzed alpha-pinene hydrogenation reaction
[ examples 8 to 11 ]
After the reaction of example 7 was completed, the organic product phase in the upper layer was removed by simple liquid separation, 40mmol of α -pinene was newly added to the catalyst phase in the lower layer, the air in the reaction vessel was replaced with hydrogen five times, and then 1.0MPa hydrogen was charged, and the reaction was carried out for 2 hours at 70 ℃ with magnetic stirring at 400 rpm. After the reaction was completed, the upper product phase was collected and quantitatively analyzed by gas chromatography.
Repeating the above steps for 3 times, collecting upper layer product phase, and performing quantitative analysis by gas chromatography. The catalytic results obtained are shown in Table 2.
TABLE 2 Recycling Performance of sodium lignosulfonate Reducedly stabilized Pt Metal nanoparticle catalysts
Comparative example 1
60.0mg of sodium lignosulfonate (96%, molecular weight: 534.51), 0.1mmol of H, which has been vacuum dried for 24 hours, are added to a stainless steel reaction kettle with a polytetrafluoroethylene lining2PtCl6·6H2O and 6mL of ultrapure water are stirred at room temperature and fully dissolved, and 40mmol of alpha-pinene is directly added into the reaction kettle. The air in the reaction vessel was replaced with hydrogen five times, and then 1.0MPa hydrogen was charged and reacted at 70 ℃ for 1.5 hours with magnetic stirring at 400 rpm. After the reaction was completed, the upper product phase was collected and quantitatively analyzed by gas chromatography.
Comparative example 2
60.0mg of sodium lignosulfonate (96 percent, molecular weight: 534.51) which has been dried in vacuum for 24 hours and 0.1mmol of PdCl are added into a stainless steel reaction kettle with a polytetrafluoroethylene lining2And 6mL of ultrapure water, fully dissolved by stirring at room temperature, heated to 80 ℃, stirred at 400rpm, reacted for 3 hours, and then cooled. Adding 40mmol of alpha-pinene into the prepared Pd nano particle catalyst with stable sodium lignosulfonate reduction, replacing air in a reaction kettle with hydrogen for five times, then filling 3.0MPa of hydrogen, and reacting for 1.5h under the magnetic stirring of 100 ℃ and 400 rpm. After the reaction was completed, the upper product phase was collected and quantitatively analyzed by gas chromatography.
Comparative example 3
60.0mg of sodium lignosulfonate (96%, molecular weight: 534.51), 0.1mmol of Na, which has been vacuum dried for 24 hours, are added to a stainless steel reaction kettle with a polytetrafluoroethylene lining2PdCl4And 6mL of ultrapure water, fully dissolved by stirring at room temperature, heated to 80 ℃, stirred at 400rpm, reacted for 3 hours, and then cooled. Adding 40mmol of alpha-pinene into the Pd nano particle catalyst with stable sodium lignosulfonate reduction, replacing air in a reaction kettle with hydrogen for five times, then filling 3.0MPa of hydrogen into the reaction kettleThe reaction was carried out at 100 ℃ for 1.5h with magnetic stirring at 400 rpm. After the reaction was completed, the upper product phase was collected and quantitatively analyzed by gas chromatography.
Comparative example 4
60.0mg of sodium lignosulfonate (96%, molecular weight: 534.51), 0.1mmol of RuCl, which has been vacuum dried for 24 hours, are added to a stainless steel reaction kettle with a polytetrafluoroethylene lining3·3H2O and 6mL of ultrapure water are fully dissolved by stirring at room temperature, heated to 80 ℃, stirred at 400rpm for reaction for 3 hours and then cooled. Adding 40mmol of alpha-pinene into the Ru nanoparticle catalyst with stable reduction of sodium lignosulfonate. The air in the reaction vessel was replaced with hydrogen five times, and then 3.0MPa hydrogen was charged and reacted at 100 ℃ for 1.5 hours with magnetic stirring at 400 rpm. After the reaction was completed, the upper product phase was collected and quantitatively analyzed by gas chromatography.
Comparative example 5
60.0mg of sodium lignosulfonate (96%, molecular weight: 534.51), 0.1mmol of RhCl, which had been vacuum dried for 24 hours, were added to a stainless steel reaction vessel with a polytetrafluoroethylene liner3·6H2O and 6mL of ultrapure water are fully dissolved by stirring at room temperature, heated to 80 ℃, stirred at 400rpm for reaction for 3 hours and then cooled. Adding 40mmol of alpha-pinene into the Rh nanoparticle catalyst with stable reduction of sodium lignosulfonate. The air in the reaction vessel was replaced with hydrogen five times, and then 3.0MPa hydrogen was charged and reacted at 100 ℃ for 1.5 hours with magnetic stirring at 400 rpm. After the reaction was completed, the upper product phase was collected and quantitatively analyzed by gas chromatography.
TABLE 3 sodium lignosulfonate reduction stabilizing metal nanoparticles prepared by other methods for catalyzing alpha-pinene hydrogenation reaction