Synthesis method of octadiene monomethyl ether

Abstract

The invention provides a synthesis method of octadiene monomethyl ether, in the synthesis method, methanol and butadiene are used as reactants for telomerization reaction, an organic amine compound is added into a reaction system as an additive, and organic amine can accelerate the coordination dissociation process of palladium ions in the telomerization reaction process and also has reducibility; divalent palladium ions in the catalyst can be rapidly reduced into zero-valent palladium in an alkaline environment, and the efficiency of telomerization reaction is improved by promoting coordination dissociation and reduction processes of the palladium ions.

Description

A method for synthesizing octadiene monomethyl ether Technical Field

[0001] This invention belongs to the field of fine chemicals and relates to a method for synthesizing octadiene monomethyl ether. Background Technology

[0002] 1-Octene, as an important comonomer and organic raw material, is mainly used in the production of high-end polyethylene, POE elastomers, PAO base oils, plasticizers, surfactants, and other high-value-added products. It is widely used in plastics, rubber, and textiles, resulting in huge demand. Currently, 1-octene production technologies mainly include wax cracking, ethylene oligomerization, and Fischer-Tropsch synthesis. Among these, wax cracking has been phased out due to its lack of competitiveness in terms of both economy and product quality; ethylene oligomerization has advantages such as high product purity and good atom economy, but also suffers from low product selectivity; Fischer-Tropsch synthesis produces high-carbon α-olefins, but because olefins and alkanes have similar boiling points, 1-octene separation is difficult and purity is low.

[0003] Researchers have developed a pyrolysis route for preparing 1-octene from methyl octyl ether, comprising the following steps: butadiene molecules undergo a telomerization reaction with methanol molecules to generate octadiene monomethyl ether (1-MOD), followed by hydrogenation purification of 1-MOD to obtain methyl octyl ether, and finally pyrolysis of methyl octyl ether to obtain the target product, 1-octene. The second and third steps exhibit high efficiency and selectivity, with near-quantitative conversion of the relevant products. Therefore, the overall efficiency of the process primarily depends on the first step, the telomerization reaction of 1,3-butadiene with methanol to generate 1-MOD. Patent EP0561779B1 discloses a method for producing 1-octene with a butadiene conversion rate of 95%, but the positive-isomer ratio is low and the reaction time is long. Patent CN115007217A discloses a polymer palladium catalyst and a method for preparing 2,7-octadiene methyl ether by catalyzing butadiene telomerization using the catalyst. In this method, the polymer palladium catalyst is used to catalyze the butadiene telomerization reaction to prepare 2,7-octadiene methyl ether. It has good stability and can be recycled. The product conversion rate is up to 100%. However, since the catalyst is in a heterogeneous solid form, the reaction time is as long as 16 hours.

[0004] Therefore, developing a synthesis method for octadiene monomethyl ether with good reaction efficiency and conversion rate is of great significance for promoting its practical application in organic feedstocks. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for synthesizing octadiene monomethyl ether. The method involves a telomerization reaction using methanol and butadiene as reactants, with an organic amine compound added as an additive. The organic amine accelerates the coordination dissociation of palladium ions during the telomerization reaction and also possesses reducing properties, rapidly reducing divalent palladium ions in the catalyst to zero-valent palladium under alkaline conditions. By promoting the coordination dissociation and reduction process of palladium ions, the efficiency of the telomerization reaction and the butadiene conversion rate are improved.

[0006] This invention provides a method for synthesizing octadiene monomethyl ether, characterized in that the synthesis method includes the following steps:

[0007] After adding solvent, methanol, phosphine-palladium catalyst, alkaline compound and additives to the reactor, butadiene is added to the reactor to carry out a telomerization reaction to obtain octadiene monomethyl ether;

[0008] The additives include organic amine compounds.

[0009] In one alternative embodiment, the organic amine compound includes one or more of triethylamine, tri-n-propylamine, triisoamylamine, n-butylamine, butyl acetate, and benzylamine.

[0010] In one alternative embodiment, the phosphine-palladium catalyst comprises a soluble palladium salt and a phosphine compound, preferably, the phosphine compound comprises a monophosphine compound.

[0011] In one alternative embodiment, the monophosphine compound includes one or more of triphenylphosphine, tris(3-methoxyphenyl)phosphine, tris(2-methylphenyl)phosphine, tris(3-fluorophenyl)phosphine, (2-hydroxyphenyl)diphenylphosphine, tributyl phosphite, tris(2-fluorophenyl)phosphine, tris(3-fluorophenyl)phosphine, and tris(pentafluorophenyl)phosphine.

[0012] In one alternative embodiment, the soluble palladium salt includes one or more of palladium acetylacetonate, palladium acetate, and palladium chloride.

[0013] In one optional embodiment, the alkaline compound includes one or both of sodium methoxide and sodium hydroxide, preferably sodium methoxide.

[0014] In one alternative embodiment, the solvent includes one or more of methanol, hexane, and cyclohexane.

[0015] In one optional embodiment, the molar ratio of the additive, the alkaline compound, the phosphine-palladium catalyst, and the butadiene is (0.001-0.006):(0.001-0.007):(0.00005-0.0005):1.

[0016] In one optional embodiment, the molar ratio of the phosphine compound to the butadiene is (0.0000001 to 0.001):1.

[0017] In one optional embodiment, the temperature of the telomerization reaction is 25–110°C, preferably 40–90°C;

[0018] The polymerization reaction takes 0.1 to 6 hours, preferably 0.5 to 3 hours.

[0019] The implementation of this invention has at least the following advantages:

[0020] This invention develops a method for synthesizing octadiene methyl ether, using methanol and butadiene as reactants in a telomerization reaction. An organic amine compound is added as an additive to the reaction system. On one hand, the organic amine accelerates the coordination dissociation process of palladium ions with organophosphorus ligands; on the other hand, the organic amine possesses reducing properties, rapidly reducing palladium ions to zero-valent palladium under alkaline conditions. Zero-valent palladium is the catalytically active component. In this synthesis method, by promoting the coordination dissociation and reduction process of palladium ions, the efficiency of the telomerization reaction and the butadiene conversion rate are improved, ultimately achieving a butadiene conversion rate as high as 95% within 30 minutes. Attached Figure Description

[0021] Figure 1 is a gas chromatogram of the reaction solution in Example 1 of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0023] 1-Octene, as an important comonomer and organic raw material, is widely used in plastics, rubber, and textiles, with huge demand. Researchers have developed a method for preparing 1-octene from methyl octyl ether via a cracking process. In this method, two butadiene molecules react with one methanol molecule in a telomerization reaction to generate 1-MOD. The 1-MOD is then hydrogenated and purified to obtain methyl octyl ether, which is finally cracked to yield the target product, 1-octene. The second and third steps of the reaction exhibit high efficiency and selectivity, and the overall efficiency depends primarily on the telomerization reaction that produces 1-MOD.

[0024] The telomerization reaction of butadiene generally uses butadiene and methanol as raw materials and soluble palladium salts and phosphine compounds as catalysts. However, the catalytically active component is zero-valent palladium. Therefore, it is often necessary to add a reducing agent to the telomerization reaction system to reduce palladium ions to zero-valent palladium, thereby catalyzing the telomerization reaction. Thus, the reduction efficiency of palladium ions will significantly affect the rate of the telomerization reaction by affecting the generation of the catalytically active component. Currently, commonly used catalysts for the telomerization reaction of 1-MOD generally suffer from problems such as low reaction rate and excessively long reaction time.

[0025] Based on this, the present invention provides a method for synthesizing octadiene monomethyl ether, characterized in that the synthesis method includes the following steps:

[0026] After adding solvent, methanol, phosphine-palladium catalyst, alkaline compound and additives to the reactor, butadiene is added to the reactor to carry out a telomerization reaction to obtain octadiene monomethyl ether;

[0027] The additives include organic amine compounds.

[0028] Telogenization is a reaction that produces oligomers in the presence of a telogenizing agent, and it belongs to the category of polymerization reactions. In this invention, under catalysis, a double bond of butadiene undergoes an electrophilic addition reaction with a hydroxyl group of methanol to form an intermediate. This intermediate can further react with another butadiene molecule to form an oligomer or a specific ether compound.

[0029] The catalyst used in the telomerization reaction is a phosphine-palladium catalyst, in which palladium ions form complexes with phosphine compounds through coordinate bonds. Since zero-valent palladium is the actual catalytic agent in the telomerization reaction, a reducing agent needs to be added to reduce the palladium ions.

[0030] This invention selects organic amine compounds as reducing agents. The nitrogen atoms in organic amine molecules possess lone pairs of electrons, which can coordinate with palladium ions to form an amine-palladium complex. This accelerates the coordination dissociation process of palladium ions with phosphine compounds. Furthermore, once the amine-palladium complex is formed, the organic amine can reduce palladium ions to zero-valent palladium through electron transfer, thereby catalyzing the telomerization reaction. Simultaneously, the amine compounds are basic, and an alkaline environment promotes reduction reactions, especially those involving metal ions. Therefore, this invention considers using organic amine compounds as additives to improve the reaction rate of the telomerization reaction.

[0031] In addition, the reduction of palladium ions by organic amine compounds requires an alkaline environment. Therefore, adding alkaline compounds to the telomerization reaction system is beneficial to improve the efficiency of the telomerization reaction by increasing the reduction efficiency of palladium ions.

[0032] This invention does not limit the type of reactor, as long as it can provide high-pressure, vacuum reaction conditions. In one specific embodiment, the reactor can be selected from a stainless steel autoclave.

[0033] On the one hand, butadiene is a flammable and highly reactive compound, and the presence of oxygen may lead to unnecessary side reactions or form explosive mixtures. On the other hand, the telomerization reaction of this invention is quite sensitive to alkalinity, and the presence of moisture will affect the reaction process. Based on the above considerations, in order to remove oxygen and moisture from the reactor, after introducing butadiene, nitrogen gas can be used to purge the reactor multiple times before adjusting the temperature and pressure to carry out the reaction.

[0034] In one alternative embodiment, the organic amine compound includes one or more of triethylamine, tri-n-propylamine, triisoamylamine, n-butylamine, butyl acetate, and benzylamine.

[0035] Organic amine compounds have an amino group, and the nitrogen atom in the amino group has a lone pair of electrons, which can directly form a coordinate bond with palladium ions. This promotes the coordination dissociation process of palladium ions with phosphine compounds. After the palladium ions dissociate with the phosphine compounds, the electrons in the nitrogen atom reduce the palladium ions to zero-valent palladium through electron transfer. Zero-valent palladium acts as a catalytically active component to catalyze the reaction of methanol and butadiene to generate the product 1-MOD.

[0036] The structure of different organic amine compounds affects their ability to act as reducing agents. Branched or cyclic structures may affect the electron-donating capacity of the amine. Among them, triethylamine and tri-n-propylamine, due to their tertiary amine structure, have stronger reducing power. In addition, the solubility of organic amine compounds affects their dispersibility in the reaction medium and their compatibility with other substances. Longer alkyl chains or aromatic rings (such as benzylamine) can alter the solubility of amines. At the same time, the coordination ability of organic amine compounds can also affect the catalyst activity by influencing their binding ability with metal ions. Based on the above considerations, selecting the above-mentioned amine compounds as reducing agents can achieve better catalytic effects.

[0037] In one alternative embodiment, the phosphine-palladium catalyst comprises a soluble palladium salt and a phosphine compound, preferably, the phosphine compound comprises a monophosphine compound.

[0038] Phosphine compounds refer to compounds containing one or more phosphine groups, while monophosphine compounds refer to organic compounds containing only one phosphine group. Compared to polyphosphine compounds, monophosphine ligands typically have less steric hindrance, which facilitates the coordination of palladium ions with phosphine groups, thus improving the stability of phosphine-palladium compounds. Furthermore, monophosphine compounds offer greater flexibility, allowing for more free adjustment of their configuration to accommodate different intermediates and transition states in the telomerization reaction process. This helps optimize the reaction pathway and improve reaction efficiency, making monophosphine compounds more advantageous as ligands.

[0039] In one alternative embodiment, the monophosphine compound includes one or more of triphenylphosphine (compound L1), tris(3-methoxyphenyl)phosphine (compound L2), tris(2-methylphenyl)phosphine (compound L3), tris(3-fluorophenyl)phosphine (compound L4), (2-hydroxyphenyl)diphenylphosphine (compound L5), tributyl phosphite (compound L6), tris(2-fluorophenyl)phosphine (compound L7), tris(3-fluorophenyl)phosphine (compound L8), and tris(pentafluorophenyl)phosphine (compound L9).

[0040] The structural formulas of the above monophosphine compounds are shown below:

[0041]

[0042]

[0043] In one optional embodiment, the soluble palladium salt includes one or more of palladium acetylacetonate, palladium acetate, and palladium chloride. The soluble palladium salt provides palladium ions, which are reduced by an organic amine compound under alkaline conditions to zero-valent palladium, which is the catalytically active component of the catalyst. As a noble metal element, reducing the amount of palladium used or recycling it can lower the cost of preparing 1-MOD, which is beneficial for the application and development of 1-octene in the raw material chemical industry.

[0044] In this invention, the monophosphine compounds and soluble palladium salts listed above can be used as catalysts in any combination according to different reaction requirements.

[0045] In one optional embodiment, the alkaline compound includes one or both of sodium methoxide and sodium hydroxide, preferably sodium methoxide. Since the catalyst is zero-valent palladium, and organic amine compounds require an alkaline environment to reduce palladium ions, they are more easily deprotonated under alkaline conditions, forming a stronger reducing agent and achieving rapid reduction of palladium ions. Therefore, adding strong alkaline compounds such as sodium methoxide and sodium hydroxide to the telomerization reaction system is considered.

[0046] In one alternative embodiment, the solvent includes one or more of methanol, hexane, and cyclohexane. The choice of solvent significantly affects the rate of the chemical reaction. Selecting methanol, hexane, or cyclohexane as a solvent or a combination of solvents can provide a flexible reaction environment and optimize the rate and conversion of the telomerization reaction.

[0047] In one optional embodiment, the molar ratio of additive, alkaline compound, phosphine-palladium catalyst, and butadiene is (0.001-0.006):(0.001-0.007):(0.00005-0.0005):1.

[0048] Because the catalyst contains the noble metal palladium, using a lower amount of catalyst can reduce costs while ensuring a certain reaction rate in the telomerization reaction. The synergistic effect of organic amine compounds and basic compounds can promote the reduction of palladium ions in the catalyst, and an appropriate ratio can also suppress side reactions and improve the conversion rate of the target product 1-MOD. Based on this, the proportions of additives, basic compounds, phosphine-palladium catalyst, and butadiene are controlled within the above ranges.

[0049] In one optional embodiment, the molar ratio of phosphine compound to butadiene is (0.0000001–0.001):1. Phosphine compound, as a support for the catalytically active component, is one of the components of the catalyst. An appropriate amount of phosphine compound can effectively promote the efficiency of the telomerization reaction, and also help improve the reaction conversion rate and reduce the formation of by-products. Excessive phosphine compound not only generates more by-products but also results in waste. Based on these considerations, controlling the molar ratio of phosphine compound to butadiene within the above range can save on the synthesis cost of product 1-MOD while maintaining good catalytic activity of the phosphine-palladium catalyst.

[0050] In one optional embodiment, the temperature of the telomerization reaction is 25–110°C, preferably 40–90°C; the time of the telomerization reaction is 0.1–6 h, preferably 0.5–3 h.

[0051] An appropriate temperature range can improve the telomerization reaction rate while maintaining good selectivity. When the temperature is too low, the reaction rate is slow and the conversion rate is low; when the temperature is too high, the reaction rate is fast and the conversion rate is high, but more byproducts may be generated. The choice of reaction time is usually based on achieving a balance between the desired conversion rate and selectivity. A shorter reaction time may not be sufficient for complete conversion of the reactant butadiene, while an excessively long time may generate more byproducts or cause degradation of the 1-MOD product. Based on these considerations, controlling the reaction temperature and time within the above range enables the telomerization reaction of this invention to achieve both good butadiene conversion and 1-MOD selectivity.

[0052] In summary, in the synthesis method of this invention, an organic amine compound is added to the telomerization reaction system of butadiene, methanol, and phosphine palladium compound. By accelerating the coordination dissociation and reduction process of palladium ions, the rate of telomerization reaction and the conversion rate of butadiene are improved, thereby maintaining the conversion rate of butadiene at a high level.

[0053] The synthesis method of octadiene methyl ether provided by the present invention will be further described below with reference to specific embodiments.

[0054] Unless otherwise specified, the experimental methods used in the following embodiments can be conventional methods in the art.

[0055] In the following embodiments, unless otherwise specified, all raw materials can be obtained by commercial purchase or conventional methods.

[0056] Example 1

[0057] This embodiment provides a method for synthesizing octadiene methyl ether, including the following steps:

[0058] To a 500 mL stainless steel autoclave, add 112 mL of methanol, 0.010 g (0.056 mmol) of palladium chloride, 0.022 g (0.085 mmol) of triphenylphosphine, 0.3 g (5.55 mmol) of sodium methoxide, and 0.137 g (1.35 mmol) of triethylamine. Purge the autoclave three times with nitrogen, then pump in 56 g (1035 mmol) of butadiene. React at 60 °C for 30 min, cool to room temperature, and stop the reaction. Transfer 2 mL of the reaction solution to a headspace vial and quantify by gas chromatography. Figure 1 shows the gas chromatogram of the reaction solution in Example 1 of this invention. Figure 1 shows that the butadiene conversion rate is 93%, and the selectivity for 1-MOD is 90%.

[0059] Example 2

[0060] This embodiment provides a method for preparing octadiene monomethyl ether, the steps of which are basically the same as those in Example 1, except that:

[0061] The phosphine compound was tris(3-methoxyphenyl)phosphine 0.03 g (0.085 mmol);

[0062] Quantitative analysis by gas chromatography revealed a butadiene conversion rate of 95% and a 1-MOD selectivity of 96%.

[0063] Example 3

[0064] This embodiment provides a method for preparing octadiene monomethyl ether, the steps of which are basically the same as those in Example 1, except that:

[0065] The phosphine compound was tris(2-methylphenyl)phosphine 0.026 g (0.085 mmol);

[0066] Quantitative analysis by gas chromatography revealed that the butadiene conversion rate was 90% and the selectivity for 1-MOD was 97%.

[0067] Example 4

[0068] This embodiment provides a method for preparing octadiene monomethyl ether, the steps of which are basically the same as those in Example 1, except that:

[0069] The phosphine compound was tris(3-fluorophenyl)phosphine 0.027 g (0.085 mmol);

[0070] Quantitative analysis by gas chromatography showed that the butadiene conversion rate was 100% and the selectivity for 1-MOD was 91%.

[0071] Example 5

[0072] This embodiment provides a method for preparing octadiene monomethyl ether, the steps of which are basically the same as those in Example 1, except that:

[0073] The phosphine compound was (2-hydroxyphenyl)diphenylphosphine 0.024 g (0.085 mmol);

[0074] Quantitative analysis by gas chromatography revealed that the butadiene conversion rate was 92% and the selectivity for 1-MOD was 93%.

[0075] Example 6

[0076] This embodiment provides a method for preparing octadiene monomethyl ether, the steps of which are basically the same as those in Example 1, except that:

[0077] The phosphine compound was 0.021 g (0.085 mmol) of tributyl phosphite;

[0078] Quantitative analysis by gas chromatography revealed that the butadiene conversion rate was 90% and the selectivity for 1-MOD was 94%.

[0079] To compare the effects of different types of phosphine compounds on butadiene conversion and 1-MOD selectivity, relevant information from Examples 1-6 is shown in Table 1 below:

[0080] Table 1

[0081]

[0082] As shown in Table 1 above, when the phosphine compound in the catalyst is a monophosphine compound, the butadiene conversion rate in this telomerization reaction is above 90%, and the selectivity of the product 1-MOD is also above 90%, indicating that the synthesis method of 1-MOD in this invention has good butadiene conversion rate and 1-MOD selectivity.

[0083] Example 7

[0084] This embodiment provides a method for preparing octadiene monomethyl ether, the steps of which are basically the same as those in Example 1, except that:

[0085] The amine compound was tri-n-propylamine, 0.186 g (1.3 mmol).

[0086] Quantitative analysis by gas chromatography revealed that the butadiene conversion rate was 96% and the selectivity for 1-MOD was 91%.

[0087] Example 8

[0088] This embodiment provides a method for preparing octadiene monomethyl ether, the steps of which are basically the same as those in Example 1, except that:

[0089] The amine compound was benzylamine, 0.139 g (1.3 mmol);

[0090] Quantitative analysis by gas chromatography revealed that the butadiene conversion rate was 95% and the selectivity for 1-MOD was 94%.

[0091] Example 9

[0092] This embodiment provides a method for preparing octadiene monomethyl ether, the steps of which are basically the same as those in Example 1, except that:

[0093] The amine compound was triethylamine, 0.274 g (2.6 mmol).

[0094] Quantitative analysis by gas chromatography revealed that the butadiene conversion rate was 95% and the selectivity for 1-MOD was 93%.

[0095] Example 10

[0096] This embodiment provides a method for preparing octadiene monomethyl ether, the steps of which are basically the same as those in Example 1, except that:

[0097] The amine compound was triethylamine, 0.411 g (3.9 mmol);

[0098] Quantitative analysis by gas chromatography revealed that the butadiene conversion rate was 97% and the selectivity for 1-MOD was 95%.

[0099] Example 11

[0100] This embodiment provides a method for preparing octadiene monomethyl ether, the steps of which are basically the same as those in Example 1, except that:

[0101] The amine compound was triethylamine, 0.685 g (6.5 mmol).

[0102] Quantitative analysis by gas chromatography revealed that the butadiene conversion rate was 99% and the selectivity for 1-MOD was 96%.

[0103] To compare the effects of the type and content of organic amine compounds on butadiene conversion and 1-MOD selectivity, relevant information from Examples 1 and 7-11 is shown in Table 2 below:

[0104] Table 2

[0105]

[0106] As shown in Table 2 above, comparing Examples 1 and 7-8, it can be seen that the type of amine compound affects the conversion rate of butadiene and the selectivity of 1-MOD. Among them, the conversion rate of butadiene is the highest when the amine compound is tri-n-propylamine, and the selectivity of 1-MOD is the highest when the amine compound is benzylamine. Comparing Examples 1 and 9-11, it can be seen that when the type of amine compound is the same, the conversion rate of butadiene and the selectivity of 1-MOD also increase with the increase of the amount of amine compound added, indicating that the content of organic amines affects the conversion rate and selectivity of the telomerization reaction in this invention.

[0107] Example 12

[0108] This embodiment provides a method for preparing octadiene monomethyl ether, the steps of which are basically the same as those in Example 1, except that:

[0109] The polymerization reaction time is 10 min;

[0110] Quantitative analysis by gas chromatography revealed that the butadiene conversion rate was 80% and the selectivity for 1-MOD was 90%.

[0111] Example 13

[0112] This embodiment provides a method for preparing octadiene monomethyl ether, the steps of which are basically the same as those in Example 1, except that:

[0113] The polymerization reaction time is 40 min;

[0114] Quantitative analysis by gas chromatography revealed that the butadiene conversion rate was 95% and the selectivity for 1-MOD was 92%.

[0115] Example 14

[0116] This embodiment provides a method for preparing octadiene monomethyl ether, the steps of which are basically the same as those in Example 1, except that:

[0117] The polymerization reaction time is 50 min;

[0118] Quantitative analysis by gas chromatography revealed that the butadiene conversion rate was 95% and the selectivity for 1-MOD was 92%.

[0119] Example 15

[0120] This embodiment provides a method for preparing octadiene monomethyl ether, the steps of which are basically the same as those in Example 1, except that:

[0121] The temperature for the telomerization reaction is 30°C;

[0122] Quantitative analysis by gas chromatography revealed that the butadiene conversion rate was 90% and the selectivity for 1-MOD was 92%.

[0123] Example 16

[0124] This embodiment provides a method for preparing octadiene monomethyl ether, the steps of which are basically the same as those in Example 1, except that:

[0125] The temperature for the telomerization reaction is 45℃;

[0126] Quantitative analysis by gas chromatography revealed that the butadiene conversion rate was 92% and the selectivity for 1-MOD was 91%.

[0127] Example 17

[0128] This embodiment provides a method for preparing octadiene monomethyl ether, the steps of which are basically the same as those in Example 1, except that:

[0129] The temperature for the telomerization reaction is 80℃;

[0130] Quantitative analysis by gas chromatography revealed that the butadiene conversion rate was 96% and the selectivity for 1-MOD was 90%.

[0131] To compare the effects of temperature and time on butadiene conversion and 1-MOD selectivity in the telomerization reaction, relevant information from Example 1 and Comparative Examples 12-17 is shown in Table 3 below:

[0132] Table 3

[0133]

[0134]

[0135] As shown in Table 3 above, comparing Example 1 and Examples 12-13, it can be seen that the reaction time affects the butadiene conversion rate, and the longer the reaction time, the higher the butadiene conversion rate, but the reaction time has little effect on the 1-MOD selectivity; comparing Example 1 and Examples 14-17, it can be seen that the reaction temperature affects the butadiene conversion rate, and the higher the reaction temperature, the higher the butadiene conversion rate, but the reaction time has little effect on the 1-MOD selectivity.

[0136] Comparative Example 1

[0137] This comparative example provides a method for preparing octadiene monomethyl ether, the steps of which are basically the same as those in Example 1, except that:

[0138] No organic amine compounds were added;

[0139] Quantitative analysis by gas chromatography revealed that the butadiene conversion rate was 50% and the selectivity for 1-MOD was 90%.

[0140] Comparative Example 2

[0141] This comparative example provides a method for preparing octadiene monomethyl ether, the steps of which are basically the same as those in Example 1, except that:

[0142] No organic amine compounds were added; the polymerization reaction time was 4 hours.

[0143] Quantitative analysis by gas chromatography revealed that the butadiene conversion rate was 85% and the selectivity for 1-MOD was 90%.

[0144] To compare the effects of adding organic amine compounds to the telomerization reaction system on butadiene conversion and 1-MOD selectivity, relevant information from Example 1 and Comparative Examples 1-2 is shown in Table 4 below:

[0145] Table 4

[0146]

[0147] As shown in Table 4 above, no amine compounds were added in Comparative Examples 1 and 2, while amine compounds were added in Example 1. The butadiene conversion rates of the three were significantly different, indicating that the addition of amine compounds can significantly improve the butadiene conversion rate. However, the 1-MOD selectivity of the three did not change much, indicating that whether or not amine compounds were added had no significant effect on the 1-MOD selectivity.

[0148] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for synthesizing octadiene monomethyl ether, characterized in that, The synthesis method includes the following steps: adding a solvent, methanol, phosphine-palladium catalyst, basic compound and additive to a reactor, and then adding butadiene to the reactor to carry out a telomerization reaction to obtain the octadiene monomethyl ether; the additive includes an organic amine compound.

2. The synthesis method according to claim 1, characterized in that, The organic amine compound includes one or more of triethylamine, tri-n-propylamine, triisoamylamine, n-butylamine, butyl acetate, and benzylamine.

3. The synthesis method according to claim 1 or 2, characterized in that, The phosphine-palladium catalyst comprises a soluble palladium salt and a phosphine compound, preferably, the phosphine compound comprises a monophosphine compound.

4. The synthesis method according to claim 3, characterized in that, The monophosphine compounds include one or more of triphenylphosphine, tris(3-methoxyphenyl)phosphine, tris(2-methylphenyl)phosphine, tris(3-fluorophenyl)phosphine, (2-hydroxyphenyl)diphenylphosphine, tributyl phosphite, tris(2-fluorophenyl)phosphine, tris(3-fluorophenyl)phosphine, and tris(pentafluorophenyl)phosphine.

5. The synthesis method according to claim 3 or 4, characterized in that, The soluble palladium salt includes one or more of palladium acetylacetonate, palladium acetate, and palladium chloride.

6. The synthesis method according to any one of claims 1-5, characterized in that, The alkaline compound includes one or both of sodium methoxide and sodium hydroxide, preferably sodium methoxide.

7. The synthesis method according to any one of claims 1-6, characterized in that, The solvent includes one or more of methanol, hexane, and cyclohexane.

8. The synthesis method according to any one of claims 1-7, characterized in that, The molar ratio of the additive, the alkaline compound, the phosphine-palladium catalyst, and the butadiene is (0.001-0.006):(0.001-0.007):(0.00005-0.0005):

1.

9. The synthesis method according to claim 3, characterized in that, The molar ratio of the phosphine compound to the butadiene is (0.0000001~0.001):

1.

10. The synthesis method according to any one of claims 1-9, characterized in that, The temperature of the telomerization reaction is 25–110°C, preferably 40–90°C; the time of the telomerization reaction is 0.1–6 h, preferably 0.5–3 h.

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