Alkaline earth metal catalyst and preparation method of iso-tridecanol polyoxyethylene ether

Abstract

The invention belongs to the field of organic synthesis, and particularly relates to a preparation method of an alkaline earth metal catalyst, which comprises the following steps: (S1) carrying out first reaction on iso-tridecanol and anhydride to obtain a first reactant; (S2) carrying out second reaction on alkaline earth metal hydroxide and the first reactant to obtain a second reactant; (S3) carrying out third reaction on inorganic acid and the second reactant to obtain a third reactant; and (S4) carrying out dehydration treatment on the third reactant. The invention also relates to a method for preparing the iso-tridecanol polyoxyethylene ether, which comprises the following step of: reacting iso-tridecanol and ethylene oxide in the presence of the alkaline earth metal catalyst in a non-reactive gas environment to prepare the iso-tridecanol polyoxyethylene ether. The iso-tridecanol polyoxyethylene ether prepared by the preparation method disclosed by the invention is relatively low in polymer dispersity index, relatively low in pour point and excellent in appearance.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis technology, specifically relating to alkaline earth metal catalysts and a method for preparing isomeric tridecyl alcohol polyoxyethylene ether. Background Technology

[0002] Isotridecyl alcohol polyoxyethylene ether is obtained by grafting ethylene oxide onto isotridecyl alcohol as an initiator. It is widely used in daily chemicals, textiles, and industrial cleaning fields, and has excellent emulsifying and detergency properties.

[0003] In traditional industrial production, alkaline catalysts such as potassium hydroxide are commonly used. The anionic catalytic characteristics of these catalysts result in a wide polymer dispersibility index (PDI), leading to the presence of components with high ethylene oxide addition numbers in the product. These components can easily cause the pour point of the polymer product to rise. However, the pour points of commonly used grades in the industry are all greater than 10°C. In autumn and winter, especially for customers in northern regions, the product is already in a solid state and requires reheating before use, resulting in wasted heat resources and significant inconvenience, impacting production efficiency. Narrowly distributed isomeric tridecyl alcohol ethers, on the other hand, contain fewer components with high ethylene oxide addition numbers, effectively lowering the product's pour point and thus solving the problem of use in autumn and winter.

[0004] CN101225161B discloses a method for synthesizing isotridecyl alcohol polyoxyethylene ether, using isotridecyl alcohol and ethylene oxide as raw materials. The process involves first catalytic polymerization in the presence of boron trifluoride, followed by catalytic polymerization in the presence of a strong base. However, this process only exhibits a narrow distribution effect in the acid-catalyzed phase; subsequent strong base catalysis still results in a high ethylene oxide addition fraction, failing to achieve a low pour point effect.

[0005] CN108102084B discloses a method for preparing isomeric alcohol polyoxyethylene ethers, using isomeric alcohols and ethylene oxide as raw materials, and CaSO4 and KOH as catalysts to prepare narrow-distribution isomeric alcohol polyoxyethylene ethers. Although this method results in a narrower distribution compared to products obtained using potassium hydroxide as a single catalyst, the distribution is still relatively wide and the pour point is relatively high. Furthermore, this isomeric tridecyl alcohol ether product cannot be clarified even when heated to its melting point, affecting its appearance. Summary of the Invention

[0006] To address at least one problem existing in the prior art, the present invention provides an alkaline earth metal catalyst and a method for preparing isomeric tridecyl alcohol polyoxyethylene ether. Using the catalyst of the present invention to prepare isomeric tridecyl alcohol polyoxyethylene ether, it is possible to obtain isomeric tridecyl alcohol polyoxyethylene ether with a low polymer dispersibility index (PDI), a relatively low pour point, and an excellent appearance.

[0007] To achieve the above objectives, the first aspect of the present invention provides a method for preparing an alkaline earth metal catalyst, the method comprising the following steps:

[0008] (S1) The isomeric tridecyl alcohol is reacted with an acid anhydride to obtain the first reactant;

[0009] (S2) The alkaline earth metal hydroxide is reacted with the first reactant in a second reaction to obtain the second reactant;

[0010] (S3) The inorganic acid is reacted with the second reactant in a third reaction to obtain the third reactant;

[0011] (S4) The third reactant is dehydrated to obtain an alkaline earth metal catalyst.

[0012] The second aspect of this invention provides the application of the alkaline earth metal catalyst prepared by the aforementioned method in the preparation of isomeric tridecyl alcohol polyoxyethylene ether.

[0013] A third aspect of the present invention provides a method for preparing isotridecyl alcohol polyoxyethylene ether, the method comprising: reacting isotridecyl alcohol and ethylene oxide in the presence of an alkaline earth metal catalyst in a non-reactive gas environment to prepare the isotridecyl alcohol polyoxyethylene ether; wherein the alkaline earth metal catalyst is prepared by the above-described preparation method.

[0014] Preferably, the weight ratio of the isomeric tridecanol to the ethylene oxide is 1:(1.1-2.7);

[0015] Preferably, the amount of the alkaline earth metal catalyst added is 0.2-0.8 wt% of the weight of the isotridecyl alcohol;

[0016] Preferably, the reaction temperature is 130-165°C.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] I. The alkaline earth metal catalyst provided by this invention is used to prepare isomeric tridecyl alcohol polyoxyethylene ether. The catalyst has good compatibility with the isomeric tridecyl alcohol polyoxyethylene ether preparation system. The prepared isomeric tridecyl alcohol polyoxyethylene ether product has a low polymer dispersibility index (PDI). The narrow distribution characteristic reduces the high ethylene oxide grafting component in the prepared isomeric tridecyl alcohol ether, and the resulting product has a low pour point.

[0019] Second, conventional alkaline earth metal catalysts (such as calcium hydroxide and barium hydroxide) in existing technologies have poor compatibility with the preparation system of isotridecyl alcohol ether, resulting in a turbid appearance of the product. This turbidity is not caused by a high freezing point and cannot be completely eliminated even with heating, leading to a higher color index of the product. However, the alkaline earth metal catalyst prepared by the reaction of isotridecyl alcohol with acid anhydrides in this invention is effectively compatible with the isotridecyl alcohol ether system, which helps to ensure that the prepared isotridecyl alcohol polyoxyethylene ether product has an excellent appearance. At the same time, since the catalyst uses isotridecyl alcohol as a raw material, it remains isotridecyl alcohol polyoxyethylene ether after grafting ethylene oxide in the reaction, without introducing byproducts into the product. Detailed Implementation

[0020] The present invention will be further described below, but this does not mean that the present invention is limited to this. Any modifications made by those skilled in the art based on the described embodiments are still within the protection scope of the present invention.

[0021] The first aspect of this invention provides a method for preparing an alkaline earth metal catalyst, the method comprising the following steps:

[0022] (S1) The isomeric tridecyl alcohol is reacted with an acid anhydride to obtain the first reactant;

[0023] (S2) The alkaline earth metal hydroxide is reacted with the first reactant in a second reaction to obtain the second reactant;

[0024] (S3) The inorganic acid is reacted with the second reactant in a third reaction to obtain the third reactant;

[0025] (S4) The third reactant is dehydrated to obtain an alkaline earth metal catalyst.

[0026] In step (S1), the acid anhydride activates the terminal hydroxyl group of isotridecyl alcohol (making the hydrogen on the terminal hydroxyl group more reactive and easier to separate), and the resulting first reactant contains the activated isotridecyl alcohol. In some embodiments, the acid anhydride may be succinic anhydride and / or acetic anhydride;

[0027] Preferably, the weight ratio of the isomeric tridecanol to the acid anhydride can be (14-18):1.

[0028] Preferably, the reaction temperature of the first reaction can be 60-80°C, and the reaction time can be, for example, 30-40 min.

[0029] In step (S2), the alkaline earth metal hydroxide undergoes a second reaction with the activated isomeric tridecanol, resulting in a second reactant containing an alcohol metal compound. In some embodiments, the alkaline earth metal hydroxide is barium hydroxide and / or calcium hydroxide, and correspondingly, the alcohol metal compound is barium alkoxide or calcium alkoxide.

[0030] When the alkaline earth metal hydroxide is barium hydroxide, the weight ratio of the isotridecyl alcohol to the alkaline earth metal hydroxide is (20-23):1; or,

[0031] When the alkaline earth metal hydroxide is calcium hydroxide, the weight ratio of the isotridecyl alcohol to the alkaline earth metal hydroxide is (8-10):1.

[0032] Preferably, the reaction temperature of the second reaction can be 90-110°C, and the reaction time is, for example, 2-3 hours.

[0033] In step (S3), the inorganic acid activates the metal alcohol compound, resulting in a third reactant containing the activated metal alcohol compound, which is the crude product of the catalyst. In step (S1), the anhydride is activated on the terminal hydroxyl group of isotridecyl alcohol (-OH); in step (S3), the inorganic acid is activated on the -O-Ca group of the metal alcohol compound.

[0034] In some embodiments, the reaction temperature of the third reaction can be 80-100°C, and the reaction time can be 1.5-3 hours.

[0035] Preferably, the inorganic acid can be sulfuric acid (e.g., concentrated sulfuric acid with a mass fraction of 95-98.3%). Compared with commonly used inorganic acids such as hydrochloric acid and nitric acid, sulfuric acid has a higher boiling point, is less prone to volatilization and decomposition under heating conditions, and does not have the corrosiveness of chloride ions like in hydrochloric acid. At the same time, it can also have a better activation effect on the metal alcohol compounds.

[0036] Preferably, when the alkaline earth metal hydroxide is barium hydroxide, the weight ratio of the amount of inorganic acid to the weight of the alkaline earth metal hydroxide can be 1:(4.5-8.5); or, when the alkaline earth metal hydroxide is calcium hydroxide, the weight ratio of the amount of inorganic acid to the weight of the alkaline earth metal hydroxide can be 1:(1.5-4).

[0037] In step (S4), the dehydration process can use dehydration methods commonly used in the art, such as vacuum heating. In some embodiments, the temperature of the dehydration process can be 90-100°C, and the pressure can be -0.1 MPa(G) to -90 kPa(G).

[0038] The second aspect of this invention provides the application of the alkaline earth metal catalyst prepared by the aforementioned method in the preparation of isomeric tridecyl alcohol polyoxyethylene ether.

[0039] The third aspect of this invention provides a method for preparing isotridecyl alcohol polyoxyethylene ether, wherein isotridecyl alcohol and ethylene oxide undergo an ethoxylation reaction in the presence of an alkaline earth metal catalyst in a non-reactive gas environment to prepare isotridecyl alcohol polyoxyethylene ether with low dispersibility index, low pour point and excellent appearance.

[0040] The alkaline earth metal catalyst was prepared using the method described above.

[0041] In some embodiments, the weight ratio of the isotridecyl alcohol to the ethylene oxide in the reaction is 1:(1.1-2.7);

[0042] And / or, the amount of the alkaline earth metal catalyst added is 0.2-0.8 wt% of the weight of the isotridecyl alcohol;

[0043] And / or, the reaction temperature is 130-165°C, and the reaction time can be, for example, 0.5-2 hours.

[0044] The present invention will be further described in detail below through specific embodiments, wherein:

[0045] The isotridecyl alcohol used was produced by ExxonMobil. Unless otherwise specified, all other raw materials and reagents can be obtained through commercial channels.

[0046] Colorimetry was determined according to GB / T9282.1-2008;

[0047] Polydispersity index (PDI) was determined using a PL-GPC220 gel permeation chromatograph with tetrahydrofuran as the mobile phase.

[0048] Pour point was tested according to national standard GB / T 3535-2006.

[0049] Unless otherwise specified, the term "parts" in the following text refers to parts by weight.

[0050] Example 1 (A1)

[0051] Alkaline earth metal catalysts were prepared according to the following steps (S1)-(S4):

[0052] (S1) Under stirring, acid anhydride is added to isotridecyl alcohol to carry out the first reaction, and the first reactant is obtained;

[0053] in,

[0054] The amount of the isomeric tridecanol used is 1400 parts;

[0055] The acid anhydride is succinic anhydride, and the dosage is 100 parts;

[0056] The reaction temperature of the first reaction is 60℃ and the reaction time is 30 min.

[0057] (S2) Under stirring, an alkaline earth metal hydroxide is added to the first reactant to carry out a second reaction, yielding a second reactant; wherein,

[0058] The alkaline earth metal hydroxide is barium hydroxide, and the amount added is 70 parts;

[0059] The reaction temperature for the second reaction is 90°C, and the reaction time is 2 hours.

[0060] (S3) 98% concentrated sulfuric acid is continuously passed into the second reactant to carry out the third reaction, yielding the third reactant (i.e., the crude catalyst); wherein,

[0061] The amount of 98% concentrated sulfuric acid used is 15.5 parts;

[0062] The reaction temperature of the third reaction is controlled at 80°C and the reaction time is 1.5 h.

[0063] (S4) The crude catalyst is dehydrated under vacuum to obtain the alkaline earth metal catalyst; wherein,

[0064] The dehydration process is carried out at a temperature of 90°C and a pressure of -90 kPa (G).

[0065] The isomeric tridecyl alcohol polyoxyethylene ether is prepared according to the following steps (S5):

[0066] (S5) Isotridecyl alcohol and the alkaline earth metal catalyst prepared in step (S4) are added to a reactor under a nitrogen atmosphere. Stirring is started and the temperature is raised to 130°C (the reaction temperature). Then, ethylene oxide is introduced to carry out the reaction. After the ethylene oxide feed is complete, the pressure in the reactor tends to be constant. The resulting reactants are aged for 20 minutes to obtain the final product, isotridecyl alcohol polyoxyethylene ether.

[0067] The amount of the isomeric tridecanol used is 200 parts;

[0068] The amount of the alkaline earth metal catalyst used is 0.4 parts;

[0069] The amount of ethylene oxide used is 220 parts.

[0070] Testing revealed that the final product of the isomeric tridecyl alcohol polyoxyethylene ether had a color number of 5 hazen at 50°C, a PDI of 1.028, and a pour point of -15.8°C.

[0071] Example 2 (A2)

[0072] The procedure is the same as in Example 1, except that:

[0073] In step (S1), the amount of isotridecyl alcohol used is 1800 parts; the reaction temperature of the first reaction is 80°C and the reaction time is 40 min.

[0074] In step (S2), the amount of barium hydroxide used is 78.3 parts; the reaction temperature of the second reaction is 110°C, and the reaction time is 3 hours.

[0075] In step (S3), the amount of 98% concentrated sulfuric acid used is 9.3 parts; the reaction temperature of the third reaction is 100°C and the reaction time is 3 hours.

[0076] In step (S4), the pressure of the dehydration treatment is -90 kPa (G).

[0077] In step (S5), the amount of alkaline earth metal catalyst is 1.6 parts; the temperature is raised to 165°C; and the amount of ethylene oxide is 540 parts.

[0078] The final product of the isomeric tridecyl alcohol polyoxyethylene ether was tested and found to have a color number of 7 hazen at 50°C, a PDI of 1.021, and a pour point of 8.3°C.

[0079] Example 3 (A3)

[0080] The procedure is the same as in Example 1, except that:

[0081] In step (S1), the amount of isotridecyl alcohol used is 1600 parts; the acid anhydride is acetic anhydride, and the amount used is the same (100 parts); the reaction temperature of the first reaction is 70°C, and the reaction time is 35 min.

[0082] In step (S2), the alkaline earth metal hydroxide is calcium hydroxide, and the amount used is 200 parts; the reaction temperature of the second reaction is 100°C, and the reaction time is 2.5 h.

[0083] In step (S3), the amount of 98% concentrated sulfuric acid used is 50 parts; the reaction temperature of the third reaction is 90°C and the reaction time is 2 hours.

[0084] In step (S4), the temperature of the dehydration treatment is 100°C and the pressure is -95 kPa (G).

[0085] In step (S5), the amount of alkaline earth metal catalyst is 1 part; the temperature is raised to 150°C; and the amount of ethylene oxide is 308 parts.

[0086] Testing revealed that the final product of the isomeric tridecyl alcohol polyoxyethylene ether had a color number of 7 hazen at 50°C, a PDI of 1.023, and a pour point of -7.6°C.

[0087] Comparative Example 1 (D1)

[0088] The procedure is the same as in Example 1, except that:

[0089] In step (S1), the acid anhydride is sulfuric acid anhydride, and the amount used is the same (100 parts).

[0090] Testing revealed that the final product of the isomeric tridecyl alcohol polyoxyethylene ether had a color number of 8 hazen at 50°C, a PDI of 1.047, and a pour point of -7.9°C.

[0091] Comparative Example 2 (D2)

[0092] The procedure is the same as in Example 1, except that:

[0093] In step (S2), the alkaline earth metal hydroxide is magnesium hydroxide, and the amount used is the same (70 parts);

[0094] Testing revealed that the final product of the isomeric tridecyl alcohol polyoxyethylene ether had a color number of 8 hazen at 50°C, a PDI of 1.039, and a pour point of -9.5°C.

[0095] Comparative Example 3 (D3)

[0096] The procedure is the same as in Example 1, except that:

[0097] Steps (S1) to (S4) are not performed.

[0098] In step (S5), the alkaline earth metal catalyst is replaced with commercially available potassium hydroxide in an amount of 0.4 parts;

[0099] After the reactants have been aged, acetic acid is added for neutralization. Since the catalyst potassium hydroxide is a strong base, acetic acid is added to ensure that the product pH is neutral. The amount of acetic acid used is 0.43 parts.

[0100] Testing revealed that the final product of the isomeric tridecyl alcohol polyoxyethylene ether had a color number of 7 hazen at 50°C, a PDI of 1.163, and a pour point of 1.6°C.

[0101] Comparative Example 4 (D4)

[0102] Refer to Example 2, except that:

[0103] Steps (S1) to (S4) are not performed.

[0104] In step (S5), the alkaline earth metal catalyst is replaced with commercially available potassium hydroxide in an amount of 1.6 parts;

[0105] After the reactants have been aged, acetic acid is added for neutralization. Since the catalyst potassium hydroxide is a strong base, acetic acid is added to ensure that the product pH is neutral. The amount of acetic acid used is 1.71 parts.

[0106] Testing revealed that the final product of the isomeric tridecyl alcohol polyoxyethylene ether had a color number of 6 hazen at 50°C, a PDI of 1.115, and a pour point of 25.2°C.

[0107] Comparative Example 5 (D5)

[0108] Refer to Example 3, with the only difference being:

[0109] Steps (S1) to (S4) are not performed.

[0110] In step (S5), the alkaline earth metal catalyst is replaced with commercially available calcium hydroxide in an amount of 1 part.

[0111] Testing revealed that the final product of the isomeric tridecyl alcohol polyoxyethylene ether had a color number of 16 hazen at 50°C, a PDI of 1.094, and a pour point of 7.1°C.

[0112] A comparison of Examples 1-3 and Comparative Examples 3-5 shows that the catalyst of the present invention has a significantly better effect than conventional hydroxide catalysts in the synthesis of isomeric tridecyl alcohol polyoxyethylene ether, and the resulting product can achieve a good balance between excellent appearance, relatively low PDI, and pour point. In contrast, the comparative examples struggle to achieve a good balance between product appearance, PDI, and pour point.

[0113] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an alkaline earth metal catalyst, characterized in that, The preparation method includes the following steps: (S1) The isomeric tridecyl alcohol is reacted with an acid anhydride to obtain the first reactant; (S2) The alkaline earth metal hydroxide is reacted with the first reactant in a second reaction to obtain the second reactant; (S3) The inorganic acid is reacted with the second reactant in a third reaction to obtain the third reactant; (S4) The third reactant is dehydrated to obtain an alkaline earth metal catalyst.

2. The preparation method according to claim 1, characterized in that, In step (S1), the acid anhydride is succinic anhydride and / or acetic anhydride; preferably, the weight ratio of the isotridecyl alcohol to the acid anhydride is (14-18):1; In step (S1), the reaction temperature of the first reaction is 60-80°C, and the reaction time is, for example, 30-40 min.

3. The preparation method according to claim 1 or 2, characterized in that, In step (S2), the alkaline earth metal hydroxide is barium hydroxide and / or calcium hydroxide; Preferably, when the alkaline earth metal hydroxide is barium hydroxide, the weight ratio of the isotridecyl alcohol to the alkaline earth metal hydroxide is (20-23):1; or, Preferably, when the alkaline earth metal hydroxide is calcium hydroxide, the weight ratio of the isotridecyl alcohol to the alkaline earth metal hydroxide is (8-10):

1.

4. The preparation method according to any one of claims 1-3, characterized in that, In step (S2), the reaction temperature of the second reaction is 90-110°C, and the reaction time is, for example, 2-3 hours.

5. The preparation method according to claim 3, characterized in that, In step (S3), when the alkaline earth metal hydroxide is barium hydroxide, the weight ratio of the inorganic acid to the alkaline earth metal hydroxide is 1:(4.5-8.5); or, When the alkaline earth metal hydroxide is calcium hydroxide, the weight ratio of the amount of inorganic acid to the weight of the alkaline earth metal hydroxide is 1:(1.5-4). Preferably, the inorganic acid is sulfuric acid.

6. The preparation method according to any one of claims 1-5, characterized in that, In step (S3), the reaction temperature of the third reaction is 80-100°C, and the reaction time is, for example, 1.5-3 hours.

7. The preparation method according to any one of claims 1-6, characterized in that, In step (S4), the dehydration process is carried out at a temperature of 90-100°C and a pressure of -0.1 MPa(G) to -90 kPa(G).

8. The application of the alkaline earth metal catalyst prepared by any one of claims 1-7 in the preparation of isomeric tridecyl alcohol polyoxyethylene ether.

9. A method for preparing isomeric tridecyl alcohol polyoxyethylene ether, characterized in that, The isotridecyl alcohol polyoxyethylene ether is prepared by reacting isotridecyl alcohol and ethylene oxide in the presence of an alkaline earth metal catalyst in a non-reactive gas environment. The alkaline earth metal catalyst is prepared by any one of claims 1-7.

10. The method according to claim 10, characterized in that, The weight ratio of the isomeric tridecanol to the ethylene oxide is 1:(1.1-2.7); And / or, the amount of the alkaline earth metal catalyst added is 0.2-0.8 wt% of the weight of the isotridecyl alcohol; And / or, the reaction temperature is 130-165°C, and the reaction time is, for example, 0.5-2 hours.