A method for preparing an environmentally friendly anionic surfactant for industrial cleaning.

Abstract

This invention provides a method for preparing an environmentally friendly anionic surfactant for industrial cleaning, relating to the field of chemical materials technology. The method includes the following steps: under the catalysis of a solid acid catalyst, an isomeric alcohol and propylene oxide undergo a propoxylation reaction to obtain intermediate I; using intermediate I as raw material and sodium hydroxide as a catalyst, a propoxylation reaction and an ethoxylation reaction are carried out sequentially to obtain intermediate II; using a mixture of SO3 / air as a sulfating agent, intermediate II undergoes a sulfation reaction, followed by neutralization and homogenization to obtain the anionic surfactant. This invention first uses a solid acid catalyst to catalyze the synthesis of intermediate I, isomeric alcohol ether-2, containing two PO groups, and then replaces this with an alkaline catalyst to carry out the addition reaction of the remaining propylene oxide and ethylene oxide. The resulting intermediate II isomeric alcohol polyether has a low residual rate of isomeric alcohol and high product quality.

Description

Technical Field

[0001] This invention relates to the field of chemical materials technology, specifically to a method for preparing an environmentally friendly anionic surfactant for industrial cleaning. Background Technology

[0002] Anionic surfactants are a class of surfactants that ionize in aqueous solutions, resulting in negatively charged hydrophilic groups. They are widely used in cleaning, industrial, and personal care applications. Anionic surfactants possess strong detergency, good foaming properties, and wetting properties, but they may combine with calcium and magnesium ions in hard water to form precipitates. Isomeric alcohol polyether sulfates exhibit good biodegradability, foaming properties, and emulsifying properties, and have thus gained widespread application.

[0003] Currently, the preparation method for isomeric alcohol polyethers containing PO and EO involves using sodium hydroxide or sodium ethoxide as a catalyst to sequentially pass propylene oxide and ethylene oxide into an isomeric alcohol to obtain the isomeric alcohol polyether. This method has the following problems: high levels of unreacted isomeric alcohol residue in the polyether, affecting product quality; and if vacuum removal of unreacted alcohol is used, it can cause problems such as a darker color in subsequent sulfation products. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing an environmentally friendly anionic surfactant for industrial cleaning, which addresses the shortcomings of the existing technology. The method first uses a solid acid catalyst to catalyze the synthesis of intermediate I isomeric alcohol ether-2 containing two PO groups, and then replaces the catalyst with an alkaline catalyst to carry out the addition reaction of the remaining propylene oxide and ethylene oxide. The resulting intermediate II isomeric alcohol polyether has a low residual rate of isomeric alcohol and high product quality.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] A method for preparing an environmentally friendly anionic surfactant for industrial cleaning includes the following steps:

[0007] Under the catalysis of a solid acid catalyst, isomeric alcohols and propylene oxide undergo propoxylation to yield intermediate I, with the molecular formula C8H12. 17 O-(C3H6O)2-H;

[0008] Using intermediate I as a raw material and sodium hydroxide as a catalyst, propoxylation and ethoxylation reactions were carried out sequentially to obtain intermediate II, whose molecular formula is C8H2O. 17 O-(C3H6O)m-(C2H4O)nH;

[0009] Using a mixture of SO3 and air as the sulfating agent, it undergoes a sulfation reaction with intermediate II. After neutralization and homogenization, an anionic surfactant is obtained with the molecular formula C8H2O. 17 O-(C3H6O)m-(C2H4O)n-SO3Na, where m is 6-8 and n is 2-4.

[0010] Preferably, when preparing intermediate I, the isomeric alcohol is one of isooctanol and isodecanol; the mass ratio of the isomeric alcohol to the solid acid catalyst is (900-1100):1, and the molar ratio of the isomeric alcohol to propylene oxide is 1:(2-3).

[0011] Preferably, the solid acid catalyst is a zirconium oxide type solid acid or a titanium oxide type solid acid; the preparation method of the solid acid catalyst is as follows: a metal hydroxide is added to a sulfuric acid solution for impregnation treatment, then filtered, the filter cake is placed in a muffle furnace for calcination, cooled with the furnace and then taken out and cooled in a desiccator to obtain the catalyst.

[0012] Preferably, the metal hydroxide is zirconium hydroxide or titanium hydroxide; the concentration of the sulfuric acid solution is 1.5-2 mol / L, and the mass ratio of the metal hydroxide to the sulfuric acid solution during impregnation is 1:(18-22); the impregnation treatment time is 2-3 h; the calcination temperature is 750-850℃, and the time is 4-5 h.

[0013] Preferably, the solid acid catalyst is a zirconium oxide-alumina type solid acid. The preparation method of the solid acid catalyst is as follows: zirconium hydroxide and aluminum hydroxide are added to sulfuric acid solution and stirred and heated until the solid dissolves. After cooling to below 40°C, ammonia water is added dropwise while stirring to neutralize to pH 8-10. After the addition is completed, stirring is continued. Finally, the mixture is filtered, and the filter cake is placed in a muffle furnace for calcination. After calcination, the cake is cooled with the furnace and then removed and cooled to room temperature in a desiccator to obtain the final product.

[0014] Preferably, the mass ratio of zirconium hydroxide, aluminum hydroxide, and sulfuric acid solution is (0.9-1):0.1:30, the concentration of sulfuric acid solution is 1-2 mol / L, and the stirring and heating temperature is 68-70℃; the concentration of ammonia water is 25 wt%, the stirring speed for continued stirring is 100-300 r / min, and the time is 2-3 h; the calcination temperature is 800℃, and the time is 4-5 h.

[0015] Preferably, when preparing intermediate I, the propylene oxide is added at a temperature of 120-125°C, and the aging time is 2-4 hours after the addition is completed.

[0016] Preferably, when preparing intermediate II, the mass ratio of intermediate I to sodium hydroxide is (750-800):1.

[0017] Preferably, in preparing intermediate II, propylene oxide is first added for propoxylation reaction, the dropping temperature of propylene oxide is 125-130℃, the molar ratio of intermediate I to propylene oxide is 1:(4-6), and the mixture is aged for 2-4 hours after the dropping is completed; after the propoxylation reaction, ethylene oxide is added for ethoxylation reaction, the dropping temperature of ethylene oxide is 130-135℃, and the mixture is aged for 2-3 hours after the dropping is completed, the molar ratio of intermediate I to ethylene oxide is 1:(2-4).

[0018] Preferably, after propoxylation is completed during the preparation of intermediate I, after propoxylation is completed during the preparation of intermediate II, and after ethoxylation, cooling and degassing are required. The cooling and degassing temperature is 100°C and the time is 20-30 min.

[0019] Preferably, when preparing the target product, the volume fraction of SO3 in the SO3 / air mixture is 2-3%; the molar ratio of intermediate II to SO3 during the sulfation reaction is 1:(1.01-1.07); the temperature of the sulfation reaction is 40-45℃; and the residence time of intermediate II in the reaction tube is 1-3s.

[0020] Preferably, during neutralization, a sodium hydroxide solution with a concentration of 30-35 wt% and deionized water are used for neutralization, the pH of the neutralized solution is 7-9, the temperature during neutralization is 65-70℃, and the concentration of the target product in the neutralized solution is 70±2 wt%; the homogenization time is 3-5 h.

[0021] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0022] This invention provides a method for preparing an environmentally friendly anionic surfactant for industrial cleaning. First, an intermediate I, isomeric alcohol ether-2, containing two PO groups, is synthesized using a solid acid catalyst. Then, an alkaline catalyst is used to carry out the addition reaction of the remaining propylene oxide and ethylene oxide. The resulting intermediate II isomeric alcohol polyether has a low residual rate of isomeric alcohols, with unreacted isooctanol content ≤15%. The product exhibits good foaming and emulsifying properties and is biodegradable. Furthermore, the method of this invention is simple to operate, employing a staged catalytic reaction with a solid acid catalyst and a liquid alkaline catalyst, making the reaction process easier to carry out and suitable for industrial production. Detailed Implementation

[0023] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0024] Many specific details are set forth in the following description in order to provide a full understanding of the invention, but the invention may also be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of the invention, and not all embodiments.

[0025] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention. Example 1

[0026] Preparation of zirconium oxide type solid acid catalysts:

[0027] 1 kg of zirconium hydroxide was added to 20 kg of 2 mol / L sulfuric acid solution and impregnated for 3 h. After filtration, the filter cake was placed in a muffle furnace and calcined at 750 °C for 4 h. After calcination, the cake was cooled to 130 °C in the furnace and removed. It was then placed in a desiccator and cooled to room temperature to obtain a zirconium oxide solid acid catalyst. Example 2

[0028] Preparation of titanium dioxide-type solid acid catalysts:

[0029] 1 kg of titanium hydroxide was added to 20 kg of 2 mol / L sulfuric acid solution and impregnated for 3 h. After filtration, the filter cake was placed in a muffle furnace and calcined at 850 °C for 5 h. Then, it was cooled to 130 °C with the furnace, removed and placed in a desiccator to cool to room temperature to obtain a titanium oxide-type solid acid catalyst. Example 3

[0030] Preparation of zirconium oxide-alumina solid acid catalysts:

[0031] 0.9 kg of zirconium hydroxide and 0.1 kg of aluminum hydroxide were added to 30 kg of 2 mol / L sulfuric acid solution. The mixture was stirred and heated to 70 °C until the solid dissolved. After cooling to below 40 °C, 25 wt% ammonia water was added dropwise while stirring at 100 r / min to neutralize the solution to pH 9. After stirring for 3 h, the mixture was filtered. The filter cake was placed in a muffle furnace and calcined at 800 °C for 5 h. The furnace was then cooled to 130 °C. The cake was removed and placed in a desiccator to cool to room temperature to obtain a zirconium oxide-alumina solid acid catalyst. Example 4

[0032] A method for preparing an environmentally friendly anionic surfactant for industrial cleaning includes the following steps:

[0033] (1) After adding 0.1 kg of the zirconium oxide solid acid catalyst prepared in Example 1 and 100 kg of isooctyl alcohol to the reactor, nitrogen gas was introduced into the reactor twice for purging. Then the temperature was raised to 120°C and 90 kg of propylene oxide was slowly added dropwise to the reactor. After the addition was completed, the reactor was aged for 3 hours, cooled to 100°C and degassed for 30 minutes. After degassed, the reactor was cooled to 50°C and filtered to obtain intermediate I containing two PO.

[0034] (2) Add 190 kg of intermediate I and 0.24 kg of sodium hydroxide into the reactor. After purging the reactor with nitrogen twice, raise the temperature to 125°C and slowly add 179 kg of propylene oxide. After the addition is complete, age for 3 hours, cool to 100°C to degas for 30 minutes, then raise the temperature to 130°C and slowly add 68 kg of ethylene oxide into the reactor. After the addition is complete, age for 3 hours, cool to 100°C to degas for 30 minutes, and finally cool to 50°C to discharge the product, obtaining intermediate II, whose molecular formula is C8H. 17 O-(C3H6O)6-(C2H4O)2-H, gas chromatography analysis showed that the unreacted alcohol content in intermediate II was 15%;

[0035] (3) Intermediate II and SO3 / air mixture (SO3 volume fraction 3%) were subjected to gas-liquid contact reaction in the reaction tube of a multi-tube sulfonation reactor. The residence time of intermediate II in the reaction tube was 3s, the molar ratio of intermediate II to SO3 was 1:1.05, the reaction temperature was 40℃, after the reaction was completed, 32wt% sodium hydroxide aqueous solution and deionized water were added, and neutralization was carried out at 65℃ to pH 8. The content of the target product was controlled at 70wt%. After neutralization, the product was transferred to a homogenization tank and homogenized at room temperature for 4h to obtain the target product, anionic surfactant, with the molecular formula C8H. 17 O-(C3H6O)6-(C2H4O)2-SO3Na. Example 5

[0036] A method for preparing an environmentally friendly anionic surfactant for industrial cleaning includes the following steps:

[0037] (1) Add 0.1 kg of the titanium oxide type solid acid catalyst prepared in Example 2 and 100 kg of isooctyl alcohol to the reactor. Purge the reactor with nitrogen twice. After heating to 122°C, slowly add 90 kg of propylene oxide to the reactor. After the addition is completed, age for 3 h. After aging, cool to 100°C and degas for 30 min. Then cool to 50°C and filter to obtain intermediate I containing 2 PO.

[0038] (2) Add 190 kg of intermediate I and 0.24 kg of sodium hydroxide into the reactor. After purging the reactor with nitrogen twice, raise the temperature to 125°C and slowly add 179 kg of propylene oxide. After the addition is complete, age for 3 hours. Then, lower the temperature to 100°C and degas for 30 minutes. Then, raise the temperature to 133°C and slowly add 68 kg of ethylene oxide. After the addition is complete, age for 3 hours. Then, lower the temperature to 100°C and degas for 30 minutes. After the degassing is complete, lower the temperature to 50°C and discharge to obtain intermediate II, whose molecular formula is C8H. 17 O-(C3H6O)6-(C2H4O)2-H, gas chromatography analysis showed that the unreacted alcohol content in isooctanol polyoxypropylene ether-2 was 14%;

[0039] (3) Intermediate II was reacted with a mixture of SO3 and air (SO3 volume fraction 3.0%) in the reaction tube of a multi-tube sulfonation reactor. The residence time of intermediate II in the reaction tube was 3s, the reaction temperature was 40℃, and the molar ratio of intermediate II to SO3 was 1:1.05. After the reaction, 32wt% sodium hydroxide aqueous solution and deionized water were added, and the mixture was neutralized to pH 8 at 65℃. The active ingredient content was controlled at 70wt%. After neutralization, the mixture was transferred to a homogenization tank and homogenized at room temperature for 4h to obtain an environmentally friendly anionic surfactant for industrial cleaning. Its molecular formula is: C8H 17 O-(C3H6O)6-(C2H4O)2-SO3Na. Example 6

[0040] A method for preparing an environmentally friendly anionic surfactant for industrial cleaning includes the following steps:

[0041] (1) 0.1 kg of the zirconium oxide-alumina solid acid catalyst prepared in Example 3 and 100 kg of isooctyl alcohol were added to the reactor. Nitrogen gas was introduced into the reactor twice for purging. After heating to 120°C, 90 kg of propylene oxide was slowly added dropwise. After the addition was completed, the reactor was aged for 3 h, cooled to 100°C for degassing for 30 min, cooled to 50°C for filtration, and the product was discharged to obtain intermediate I containing 2 PO.

[0042] (2) Add 190 kg of intermediate I and 0.24 kg of sodium hydroxide into the reactor. After purging the reactor twice with nitrogen, raise the temperature to 127°C. Slowly add 179 kg of propylene oxide to the reactor. After the addition is complete, age for 3 hours. Then, lower the temperature to 100°C and degas for 30 minutes. Raise the temperature to 132°C and slowly add 68 kg of ethylene oxide. After the addition is complete, age for 3 hours. Then, lower the temperature to 100°C and degas for 30 minutes. Finally, lower the temperature to 50°C and discharge the product to obtain intermediate II, whose molecular formula is C8H. 17 O-(C3H6O)6-(C2H4O)2-H, gas chromatography analysis showed that the unreacted alcohol content in isooctanol polyoxypropylene ether-2 was 12%;

[0043] (3) Intermediate II was subjected to a gas-liquid contact reaction with a SO3 / air mixture (SO3 volume fraction of 3.0%) in a multi-tube sulfonation reactor. The residence time of intermediate II in the reaction tube was 2s, the reaction temperature was 40℃, and the molar ratio of isooctanol polyether to SO3 was 1:1.05. After the reaction, 32wt% sodium hydroxide aqueous solution and deionized water were added, and the mixture was neutralized to pH 8 at 65℃. The active ingredient content was controlled at 70wt%. After neutralization, the mixture was transferred to a homogenization tank and homogenized at room temperature for 4h to obtain an environmentally friendly anionic surfactant for industrial cleaning. Its molecular formula is: C8H 17 O-(C3H6O)6-(C2H4O)2-SO3Na. Example 7

[0044] A method for preparing an environmentally friendly anionic surfactant for industrial cleaning includes the following steps:

[0045] (1) After adding 0.1 kg of the titanium oxide type solid acid catalyst prepared in Example 2 and 100 kg of isodecanol into the reactor, nitrogen was purged twice. After heating to 121°C, 73 kg of propylene oxide was slowly added dropwise. After the addition was completed, the reactor was aged for 3 h, cooled to 100°C and degassed for 30 min. After degassed, the reactor was cooled to 50°C and filtered to obtain intermediate I containing 2 PO.

[0046] (2) 173 kg of intermediate I and 0.22 kg of sodium hydroxide were added to the reactor. After purging with nitrogen twice, the temperature was raised to 127°C. 147 kg of propylene oxide was slowly added dropwise. After the addition was completed, the mixture was aged for 3 hours. The temperature was then lowered to 100°C for degassing for 30 minutes. The temperature was then raised to 132°C, and 56 kg of ethylene oxide was slowly added dropwise to the reactor. After the addition was completed, the mixture was aged for 3 hours. The temperature was then lowered to 100°C for degassing for 30 minutes. The temperature was then lowered to 50°C, and intermediate II was obtained. Its molecular formula is C 10 H 21 O-(C3H6O)6-(C2H4O)2-H; Gas chromatography analysis showed that the unreacted alcohol content in isodecanol polyoxypropylene ether-2 was 15%;

[0047] (3) Intermediate II undergoes a gas-liquid contact reaction with a SO3 / air mixture (SO3 volume fraction of 3.0%) in the reaction tube of a multi-tube sulfonation reactor. The residence time of intermediate II in the reaction tube is 3s, the reaction temperature is 40℃, and the molar ratio of intermediate II to SO3 is 1:1.05. After the reaction, 32wt% sodium hydroxide aqueous solution and deionized water are added, and the mixture is neutralized to pH 8 at 65℃. The active ingredient content is controlled at 70wt%. After neutralization, the mixture is transferred to a homogenization tank and homogenized at room temperature for 4h to obtain an environmentally friendly anionic surfactant for industrial cleaning. Its molecular formula is: C 10H 21 O-(C3H6O)6-(C2H4O)2-SO3Na. Example 8

[0048] A method for preparing an environmentally friendly anionic surfactant for industrial cleaning includes the following steps:

[0049] (1) 0.1 kg of the zirconium oxide solid acid catalyst prepared in Example 1 and 100 kg of isooctyl alcohol were added to the reactor. Nitrogen gas was introduced into the reactor twice for purging. After heating to 125°C, 90 kg of propylene oxide was slowly added dropwise. After the addition was completed, the reactor was aged for 3 h. Then the temperature was lowered to 100°C for degassing for 30 min. Finally, the temperature was lowered to 50°C and the product was filtered out to obtain intermediate I containing 2 PO atoms.

[0050] (2) Add 190 kg of intermediate I and 0.25 kg of sodium hydroxide into the reactor. After purging the reactor with nitrogen twice, raise the temperature to 125°C and slowly add 224 kg of propylene oxide. After the addition is complete, age for 3 hours, cool to 100°C to degas for 30 minutes, then raise the temperature to 135°C and continue to slowly add 102 kg of ethylene oxide into the reactor. After the addition is complete, age for 3 hours, then cool to 100°C to degas for 30 minutes, and finally cool to 50°C to obtain intermediate II, whose molecular formula is C8H. 17 O-(C3H6O)7-(C2H4O)3-H, gas chromatography analysis showed that the unreacted alcohol content in intermediate II was 13%;

[0051] (3) Intermediate II was reacted with a mixture of SO3 and air (SO3 volume fraction 3.0%) in the reaction tube of a multi-tube sulfonation reactor. The residence time of intermediate II in the reaction tube was 3s, the reaction temperature was 40℃, and the molar ratio of intermediate II to SO3 was 1:1.05. After the reaction, 32wt% sodium hydroxide aqueous solution and deionized water were added, and the mixture was neutralized to pH 8 at 65℃. The active ingredient content was controlled at 70wt%. After neutralization, the mixture was transferred to a homogenization tank and homogenized at room temperature for 4h to obtain an environmentally friendly anionic surfactant for industrial cleaning. Its molecular formula is: C8H 17 O-(C3H6O)7-(C2H4O)3-SO3Na. Example 9

[0052] (1) After adding 0.1 kg of the zirconium oxide-alumina solid acid catalyst prepared in Example 3 and 100 kg of isodecanol into the reactor, nitrogen gas was introduced into the reactor twice for purging. After heating to 123°C, 73 kg of propylene oxide was slowly added dropwise. After the addition was completed, the reactor was aged for 3 hours, cooled to 100°C for degassing for 30 minutes, and then cooled to 50°C. The product was filtered to obtain intermediate I containing 2 PO atoms.

[0053] (2) 173 kg of intermediate I and 0.22 kg of sodium hydroxide were added to the reactor. After purging the reactor with nitrogen twice, the temperature was raised to 126 °C. 219 kg of propylene oxide was slowly added dropwise. After the addition was completed, the reactor was aged for 3 hours. Then, the temperature was lowered to 100 °C for degassing for 30 minutes. The temperature was then raised to 132 °C, and 111 kg of ethylene oxide was slowly added dropwise. After the addition was completed, the reactor was aged for 3 hours. Then, the temperature was lowered to 100 °C for degassing for 30 minutes. Finally, the temperature was lowered to 50 °C, and intermediate II was obtained. Its molecular formula is C 10 H 21 O-(C3H6O)8-(C2H4O)4-H, gas chromatography analysis showed that the unreacted alcohol content in isodecanol polyoxypropylene ether-2 was 15%;

[0054] (3) Intermediate II undergoes a gas-liquid contact reaction with a SO3 / air mixture (SO3 volume fraction 3.0%) in the reaction tube of a multi-tube sulfonation reactor. The residence time of intermediate II in the reaction tube is 3 s, the reaction temperature is 40℃, and the molar ratio of intermediate II to SO3 is 1:1.05. After the reaction, 32 wt% sodium hydroxide aqueous solution and deionized water are added, and the mixture is neutralized to pH 8 at 65℃. The active ingredient content is controlled at 70 wt%. After neutralization, the mixture is transferred to a homogenization tank and homogenized at room temperature for 4 h to obtain an environmentally friendly anionic surfactant for industrial cleaning. Its molecular formula is: C 10 H 21 O-(C3H6O)8-(C2H4O)4-SO3Na.

[0055] Comparative Example 1

[0056] A method for preparing anionic surfactants includes the following steps:

[0057] (1) After adding 0.35 kg of sodium hydroxide and 100 kg of isooctanol to the reactor, nitrogen gas was introduced into the reactor twice for purging. After heating to 125 °C, 314 kg of propylene oxide was slowly added dropwise. After the addition was completed, the reactor was aged for 3 hours, cooled to 100 °C for degassing for 30 minutes, and then heated to 135 °C. 102 kg of ethylene oxide was then slowly added dropwise. After the addition was completed, the reactor was aged for 3 hours, cooled to 100 °C for degassing for 30 minutes, and finally cooled to 50 °C. Intermediate II was obtained by discharging the product. Its molecular formula is C8H 17 O-(C3H6O)7-(C2H4O)3-H, gas chromatography analysis showed that the unreacted alcohol content in isooctanol polyether was 24%;

[0058] (2) Intermediate II was subjected to a gas-liquid contact reaction with a SO3 / air mixture (SO3 volume fraction of 3.0%) in the reaction tube of a multi-tube sulfonation reactor. The residence time of intermediate II in the reaction tube was 3 s, the reaction temperature was 40℃, and the molar ratio of intermediate II to SO3 was 1:1.05. After the reaction, 32 wt% sodium hydroxide aqueous solution and deionized water were added, and the mixture was neutralized to pH 8 at 65℃. The active ingredient content was controlled at 70 wt%. After neutralization, the mixture was transferred to a homogenization tank and homogenized at room temperature for 4 h to obtain an environmentally friendly anionic surfactant for industrial cleaning. Its molecular formula is: C8H 17 O-(C3H6O)7-(C2H4O)3-SO3Na.

[0059] Comparative Example 2

[0060] A method for preparing anionic surfactants includes the following steps:

[0061] (1) After adding 0.35 kg of the zirconium oxide solid acid prepared in Example 1 and 100 kg of isooctanol to the reactor, nitrogen was purged twice. The temperature was raised to 125°C and 314 kg of propylene oxide was slowly added dropwise. After the addition was completed, the mixture was aged for 3 hours. Then, the temperature was lowered to 100°C for degassing for 30 minutes, and then the temperature was raised to 135°C. 102 kg of ethylene oxide was slowly added dropwise. After the addition was completed, the mixture was aged for 3 hours, and then the temperature was lowered to 100°C for degassing for 30 minutes. Finally, the temperature was lowered to 50°C, and intermediate II was obtained. Its molecular formula is C8H. 17 O-(C3H6O)7-(C2H4O)3-H, gas chromatography analysis showed that the unreacted alcohol content in isooctanol polyether was 7%;

[0062] (2) Intermediate II was subjected to a gas-liquid contact reaction with a SO3 / air mixture (SO3 volume fraction of 3.0%) in the reaction tube of a multi-tube sulfonation reactor. The residence time of intermediate II in the reaction tube was 3s, the reaction temperature was 40℃, and the molar ratio of intermediate II to SO3 was 1:1.05. After the reaction, 32wt% sodium hydroxide aqueous solution and deionized water were added, and the mixture was neutralized to pH 8 at 65℃. The active ingredient content was controlled at 70wt%. After neutralization, the mixture was transferred to a homogenization tank and homogenized at room temperature for 4h to obtain an environmentally friendly anionic surfactant for industrial cleaning. Its molecular formula is: C8H 17 O-(C3H6O)7-(C2H4O)3-SO3Na.

[0063] Comparative Example 3

[0064] A method for preparing anionic surfactants includes the following steps:

[0065] (1) 0.1 kg of the zirconium oxide solid acid catalyst prepared in Example 1 and 100 kg of isooctyl alcohol were added to the reactor. Nitrogen gas was introduced into the reactor twice for purging. After heating to 124-125°C, 90 kg of propylene oxide was slowly added dropwise. After the addition was completed, the reactor was aged for 3 hours. Then, the temperature was lowered to 100°C for degassing for 30 minutes. The temperature was then lowered to 50°C for filtration to obtain intermediate I containing 2 PO atoms.

[0066] (2) 190 kg of intermediate I and 0.25 kg of sodium hydroxide were added to the reactor. After purging the reactor with nitrogen twice, the temperature was raised to 125 °C. 224 kg of propylene oxide was slowly added dropwise. After the addition was completed, the reactor was aged for 3 hours. The temperature was then lowered to 100 °C for degassing for 30 minutes. The temperature was then raised to 135 °C. 102 kg of ethylene oxide was slowly added dropwise to the reactor. After the addition was completed, the reactor was aged for 3 hours. The temperature was then lowered to 100 °C for degassing for 30 minutes. The temperature was then raised to 150 °C to remove isooctanol under vacuum at a vacuum degree of -0.095 MPa for 30 minutes. The temperature was then lowered to 50 °C to obtain intermediate II, whose molecular formula is C8H. 17 O-(C3H6O)7-(C2H4O)3-H, gas chromatography analysis showed that the unreacted alcohol content in intermediate II was 7%;

[0067] (3) Intermediate II was reacted with SO3 / air mixture (SO3 volume fraction 3.0%) in the reaction tube of a multi-tube sulfonation reactor. The residence time of intermediate II in the reaction tube was 3s, the reaction temperature was 40℃, and the molar ratio of intermediate II to SO3 was 1:1.05. After the reaction, 32wt% sodium hydroxide aqueous solution and deionized water were added, and the mixture was neutralized to pH 8 at 65℃. The active ingredient content was controlled at 70wt%. After neutralization, the mixture was transferred to a homogenization tank and homogenized at room temperature for 4h to obtain an environmentally friendly anionic surfactant for industrial cleaning. Its molecular formula is: C8H 17 O-(C3H6O)7-(C2H4O)3-SO3Na.

[0068] The performance of the surfactants in Examples 4-9 and Comparative Examples 1-3 was tested below. The test methods and results are as follows:

[0069] 1. Color

[0070] Tested using the GB / T 3143-1982 method.

[0071] 2. Foam performance

[0072] The initial foam volume and the foam volume after 5 minutes were tested using GB / T 7462-1994 (modified Ross-Miles method).

[0073] 3. Emulsifying properties

[0074] The emulsifying properties of surfactants on liquid paraffin were tested using the oscillation method, and characterized by the precipitation half-life of the liquid paraffin. The specific procedure was as follows: a 0.3 wt% surfactant solution was prepared with deionized water. 40 mL of this solution was measured using a graduated cylinder and placed in a 100 mL stoppered graduated cylinder. An equal volume of liquid paraffin was then added, and the mixture was vigorously shaken up and down 5 times. After standing for 10 seconds, the mixture was shaken vigorously up and down 5 more times. This process was repeated four times. Timing was then started, and the time when the precipitated liquid volume reached 20 mL was recorded to characterize the emulsifying properties of the sample.

[0075] 4. Biodegradability

[0076] Biodegradability was determined according to GB / T15818-2018.

[0077] The test results are shown in Table 1.

[0078] Table 1

[0079]

[0080] As can be seen from the test results in Table 1, compared with the comparative example, the embodiments of the present invention first utilize the high catalytic activity of the solid acid catalyst to effectively improve the conversion rate of isomeric alcohols and reduce the residue of unreacted isomeric alcohols. The intermediate I containing two PO groups obtained is significantly easier to propoxylate and ethoxylate compared with the corresponding isomeric alcohol. At this time, replacing the solid acid catalyst with a liquid base catalyst can not only ensure the normal progress of the reaction, but also significantly reduce the problem that the solid acid catalyst will cause an increase in reaction by-products. The obtained surfactant not only has good color, but also excellent foaming and emulsifying properties, and good degradability.

[0081] In Comparative Example 1, sodium hydroxide was used as a single catalyst, resulting in a higher content of unreacted alcohols in intermediate II and a decrease in the performance of the prepared surfactant.

[0082] In Comparative Example 2, zirconium oxide solid acid was used alone as a catalyst. Due to its high reactivity, although the content of unreacted alcohol in intermediate II was reduced, there were many byproducts, resulting in a dark color in the subsequent sulfation product and a certain impact on the product's emulsification performance.

[0083] In Comparative Example 3, the use of vacuum removal of unreacted alcohol from intermediate II can cause problems such as dark color in subsequent sulfation products.

[0084] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention, including the best mode, and also enables any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combination of methods.

[0085] It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements similar to those expressed in the claims, or if they include equivalent structural elements that are not substantially different from those expressed in the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A process for the preparation of an environmentally friendly anionic surfactant for industrial cleaning, characterized by, The method comprises the following steps: In the presence of a solid acid catalyst, isomeric alcohol and propylene oxide are subjected to propoxylation to obtain intermediate I, whose molecular formula is C8H 17 O-(C3H6O)2-H; the isomeric alcohol is isooctanol; the solid acid catalyst is a zirconium oxide type catalyst or a titanium oxide type catalyst or a zirconium oxide-aluminum oxide type solid acid; The preparation method of the zirconia-titania type catalyst is as follows: the metal hydroxide is immersed in a sulfuric acid solution, then filtered, and the filter cake is placed in a muffle furnace for calcination, cooled in the furnace, taken out, and cooled in a desiccator to obtain the zirconia-titania type catalyst; The preparation method of the zirconia-alumina type solid acid is as follows: the zirconium hydroxide and the aluminum hydroxide are added into a sulfuric acid solution, heated and stirred until the solid is dissolved, then cooled to below 40 DEG C, and while stirring, ammonia water is added dropwise until the pH is 8-10, and then the stirring is continued, and finally filtered, and the filter cake is placed in a muffle furnace for calcination, cooled in the furnace, taken out, and cooled to room temperature in a desiccator to obtain the zirconia-alumina type solid acid. The intermediate I is used as raw material, sodium hydroxide is used as catalyst, and propoxylation reaction and ethoxylation reaction are sequentially carried out to obtain intermediate II, which has a molecular formula of C8H 17 O-(C3H6O)m-(C2H4O)n-H; the mass ratio of intermediate I to sodium hydroxide is (750-800):1; the dropwise addition temperature of propylene oxide is 125-130 DEG C, the molar ratio of intermediate I to propylene oxide is 1:(4-6), and aging is performed for 2-4 h after dropwise addition is completed; the dropwise addition temperature of ethylene oxide is 130-135 DEG C, aging is performed for 2-3 h after dropwise addition is completed, and the molar ratio of intermediate I to ethylene oxide is 1:(2-4); The intermediate II is sulfated with a mixed gas of SO3 / air, and then neutralized and homogenized to obtain an anionic surfactant with the molecular formula: C8H 17 O-(C3H6O)m-(C2H4O)n-SO3Na, m is 6-8, and n is 2-4.

2. A process for the preparation of an environmentally friendly anionic surfactant for industrial cleaning according to claim 1, characterized in that, In the preparation of the intermediate I, the mass ratio of the isomerized alcohol to the solid acid catalyst is (900-1100):1, and the molar ratio of the isomerized alcohol to the propylene oxide is 1:(2-3).

3. A process for the preparation of an environmentally friendly anionic surfactant for industrial cleaning according to claim 1, characterized in that, In the preparation of the zirconia-titania type catalyst, the metal hydroxide is zirconium hydroxide or titanium hydroxide, the concentration of the sulfuric acid solution is 1.5-2 mol / L, the mass ratio of the metal hydroxide to the sulfuric acid solution during the immersion is 1:(18-22), the immersion treatment time is 2-3 h, and the calcination temperature is 750-850 DEG C for 4-5 h.

4. A process for the preparation of an environmentally friendly anionic surfactant for industrial cleaning according to claim 1, characterized in that, In the preparation of the zirconia-alumina type solid acid, the mass ratio of the zirconium hydroxide, the aluminum hydroxide, and the sulfuric acid solution is (0.9-1):0.1:30, the concentration of the sulfuric acid solution is 1-2 mol / L, the stirring and heating temperature is 68-70 DEG C, the concentration of the ammonia water is 25 wt%, the stirring speed during the continued stirring treatment is 100-300 r / min, the stirring treatment time is 2-3 h, and the calcination temperature is 800 DEG C for 4-5 h.

5. A process for the preparation of an environmentally friendly anionic surfactant for industrial cleaning according to claim 1, characterized in that, In the preparation of the intermediate I, the dropping temperature of the propylene oxide is 120-125 DEG C, and the aging time after the dropping is completed is 2-4 h.

6. A process for the preparation of an environmentally friendly anionic surfactant for industrial cleaning according to claim 1, characterized in that, After the propoxylation is completed in the preparation of the intermediate I, after the propoxylation is completed in the preparation of the intermediate II, and after the ethoxylation is completed, cooling and degassing are required, the cooling and degassing temperature is 100 DEG C, and the cooling and degassing time is 20-30 min.

7. A process for the preparation of an environmentally friendly anionic surfactant for industrial cleaning according to claim 1, characterized in that, In the preparation of the target product, the volume fraction of SO3 in the SO3 / air mixed gas is 2-3%, the molar ratio of the intermediate II to SO3 during the sulfation reaction is 1:(1.01-1.07), the sulfation reaction temperature is 40-45 DEG C, and the residence time of the intermediate II in the reaction tube is 1-3 s.

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