A short carbon alkyl glycoside and its preparation method and application

Abstract

The present invention relates to a short-chain alkyl glycoside and a preparation method and application thereof, belonging to the technical field of surfactants. The preparation method comprises the following steps: (1) mixing a first portion of a short-chain alcohol with glucose to obtain a mixed solution; (2) mixing the mixed solution obtained in step (1) with a second portion of a short-chain alcohol and a branched alkylbenzene sulfonic acid catalyst, reacting, removing the branched alkylbenzene sulfonic acid catalyst, and obtaining the short-chain alkyl glycoside. The present invention obtains a bubble-free short-chain alkyl glycoside by using a specific type of catalyst in combination with a specific process. The short-chain alkyl glycoside has no turbidity range when diluted, has a low by-product content, can meet its use conditions at low concentrations, and broadens the application field of the short-chain alkyl glycoside.

Description

Technical Field

[0001] The invention relates to the technical field of surfactants, and in particular to a short-carbon alkyl glycoside and a preparation method and application thereof. Background Art

[0002] Alkyl polyglycosides are known as a new generation of "green surfactants". They have the characteristics of both nonionic and anionic surfactants and exhibit different properties depending on the hydrophobic chain. Generally speaking, medium and long carbon chain alkyl polyglycosides have excellent foaming, wetting, emulsifying and detergency properties, and are suitable for personal care and household cleaning. Short carbon chain alkyl polyglycosides are resistant to strong alkalis and have low or no foaming properties, and are suitable for industrial and public engineering cleaning.

[0003] At present, the synthesis process of alkyl glycosides is relatively mature, but short-chain alkyl glycosides still generally have problems such as turbidity intervals when diluted with water. Whether it is the direct glycoside method or the transglycoside method, it is crucial to choose the right process and catalyst. At present, the catalysts used by mainstream manufacturers in the synthesis section of alkyl glycosides are p-toluenesulfonic acid, dodecylbenzenesulfonic acid or their composite catalysts. P-toluenesulfonic acid is more active, and the short-carbon alkyl glycosides synthesized with it have low foam, high by-product content, and turbidity intervals when diluted with water. Dodecylbenzenesulfonic acid is used as a catalyst to synthesize short-chain alkyl glycosides. There is no turbidity interval when diluted with water, but the foam of alkyl glycosides is increased. In industrial cleaning, many working conditions do not require foam. Rich foam will affect the cleaning and rinsing effects. The development of a short-chain alkyl glycoside that is foam-free and has no turbidity interval when diluted with water is imminent. There are also related studies using solid acids, strong acid ion exchange resins and enzymes as catalysts. Solid acids and enzymes are expensive, and the catalysts are easily deactivated during use, making industrialization difficult. Sulfonic acid benzaldehyde resin and polystyrene cation exchange resin are unstable at temperatures above 100°C and may undergo thermal decomposition. In addition, the ion exchange resin and the alkyl glycoside synthesis raw materials are solid-liquid two-phase, and their catalytic capacity is limited.

[0004] It has been reported in the prior art that a mixed acid catalyst is prepared with dodecylbenzenesulfonic acid, the catalyst dosage is 3% of the mass of glucose, the alcohol-sugar molar ratio is 5:1, and the reaction time is 10 hours. 2-ethylhexyl glucoside is synthesized by direct glycosidation method, but the catalyst addition amount is large and the synthesis time is long. The obtained 2-ethylhexyl glucoside belongs to low foam type and has strong foam stability. CN111363770A discloses a synthesis process of surfactant hexyl glucoside, which uses glucose as raw material and β-glucosidase as catalyst to synthesize hexyl glucoside. The conversion rate of glucose is only 30.12%, and the synthesized product has high foam, and no foam product can be obtained.

[0005] Therefore, how to solve the problems of dilution and turbidity of short-carbon alkyl glycosides and high by-product content in the preparation of foam-free short-carbon alkyl glycosides has become an urgent problem to be solved. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a short-chain alkyl glycoside and a preparation method and application thereof. In order to solve the problems of turbidity when diluted with water and high by-product content of short-chain alkyl glycoside, a foam-free short-chain alkyl glycoside with no turbidity when diluted with water is prepared by adopting a specific catalyst and preparation process. The product has a high yield, a short synthesis time, a small amount of catalyst, and simple product process operation.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for preparing a short carbon alkyl glycoside, the preparation method comprising the following steps:

[0009] (1) mixing the first portion of the short-chain alcohol with glucose to obtain a mixed solution;

[0010] (2) The mixed solution obtained in step (1) is mixed with the second part of the short-chain alcohol and the branched alkylbenzene sulfonic acid catalyst, and the reaction is carried out to remove the branched alkylbenzene sulfonic acid catalyst to obtain the short-chain alkyl glycoside.

[0011] The method for preparing short-carbon alkyl glycoside provided by the present invention adopts a branched alkylbenzene sulfonic acid compound as a catalyst. The acidity coefficient of the branched alkylbenzene sulfonic acid compound is lower than that of traditional p-toluenesulfonic acid, etc., and it is not easy to form by-products such as polyalkyl glycoside when catalyzing the reaction of glycoside. At the same time, it is also an anionic surfactant, which helps the reaction materials to form an emulsion form and accelerate the reaction process. The branched alkylbenzene sulfonic acid is removed in time after the reaction. The obtained alkyl glycoside is free of bubbles and has a low by-product content. It is not turbid when diluted with water and can meet the working conditions of its use at a low concentration. The product does not contain sulfur, which can avoid harm to the environment, broadens the application scope of the short-carbon alkyl glycoside, and has important application value.

[0012] Preferably, the short carbon chain alcohol includes a C4-C10 (eg, C5, C6, C7, C8 or C9) straight chain or branched chain alcohol.

[0013] Preferably, the short-chain alcohol includes any one of n-hexanol, n-heptanol or isooctyl alcohol, or a combination of at least two of them.

[0014] Preferably, taking the total mass of the first part of short-chain alcohols and the second part of short-chain alcohols as 100%, the mass of the first part of short-chain alcohols is 1-99%, for example, it can be 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the said range.

[0015] Preferably, the mass ratio of the first part of short-chain alcohol to glucose is (1-4): 1, wherein the specific value of (1-4) can be, for example, 1.5, 2, 2.5, 3 or 3.5, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0016] Preferably, the molar ratio of the total molar amount of the first part of the short-chain alcohol and the second part of the short-chain alcohol to glucose is (1-10):1, wherein the specific value of (1-10) can be, for example, 2, 3, 4, 5, 6 or 8, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0017] Preferably, the mixing method includes homogenization.

[0018] Preferably, the homogenization speed is 5000-30000 rpm, for example, it can be 6000 rpm, 8000 rpm, 10000 rpm, 15000 rpm, 20000 rpm or 25000 rpm, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0019] Preferably, the homogenization time is 1-30 min, for example, it can be 2 min, 5 min, 8 min, 10 min, 15 min, 20 min or 25 min, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0020] Preferably, the volume average particle size of the material in the mixed liquid is 1-100 μm, for example, it can be 2 μm, 5 μm, 10 μm, 20 μm, 30 μm, 50 μm or 80 μm, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0021] As a preferred technical solution of the present invention, the particle size of glucose particles is refined by homogenization, so that the alcohol sugar is in a relatively stable suspended state. The sedimentation time of unhomogenized glucose when stationary is 1-3 minutes, while it takes 1-2 hours for the glucose to completely sink to the bottom when stationary after homogenization; combined with specific catalysts and process steps, the reaction time of the synthesis is further shortened, the generation of by-products is reduced, and a bubble-free short-chain alkyl glycoside product is obtained.

[0022] Preferably, the branched alkylbenzene sulfonic acid catalyst includes branched octylbenzene sulfonic acid and / or branched dodecylbenzene sulfonic acid.

[0023] For example, the branched alkylbenzene sulfonic acid catalyst may be a commercially available product, for example, the branched octylbenzene sulfonic acid of Shandong Yousuo Chemical Technology Co., Ltd., which has the following structure:

[0024] .

[0025] Preferably, the mass ratio of glucose to branched alkylbenzene sulfonic acid catalyst is 1:(0.001-0.1), wherein the specific value of (0.001-1) can be, for example, 0.005, 0.01, 0.05, 0.1, 0.2, 0.5 or 0.8, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0026] Preferably, the mixing pressure in step (2) is 100-30000Pa, for example, it may be 500Pa, 1000Pa, 1500Pa, 3000Pa, 5000Pa, 8000Pa, 10000Pa or 20000Pa, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0027] Preferably, the mixing temperature in step (2) is 60-130°C, for example, 70°C, 80°C, 90°C, 100°C, 110°C or 120°C, as well as specific values ​​between the above-mentioned points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0028] Preferably, the mixing time in step (2) is 0.5-2 h, for example, 0.6 h, 0.8 h, 1 h, 1.2 h, 1.5 h or 1.8 h, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0029] Preferably, the reaction time is 2-10 h, for example, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h or 9 h, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0030] Preferably, the reaction temperature is 60-130°C, for example, 70°C, 80°C, 90°C, 100°C, 110°C or 120°C, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0031] Preferably, the method of removing the branched alkylbenzene sulfonic acid catalyst comprises adsorption using a strong basic anion exchange resin.

[0032] Preferably, the adsorption temperature is 30-95°C, for example, it can be 35°C, 40°C, 50°C, 60°C, 70°C, 80°C or 90°C, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0033] Preferably, the adsorption time is 10-300 min, for example, it can be 20 min, 50 min, 80 min, 100 min, 150 min, 200 min or 250 min, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0034] Preferably, the mass ratio of the strong basic anion exchange resin to the branched alkylbenzene sulfonic acid catalyst is (1-5):1, wherein the specific value of (1-5) can be, for example, 1.5, 2, 2.5, 3, 3.5, 4 or 4.5, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0035] Preferably, the particle size of the strongly basic anion exchange resin is 0.32-1.3 mm, for example, it can be 0.35 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.8 mm, 1 mm or 1.2 mm, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0036] The exchange capacity of the strong basic anion exchange resin is ≥1 mol / L, for example, it can be 1.2 mol / L, 1.5 mol / L, 1.8 mol / L, 2 mol / L, 2.5 mol / L or 3 mol / L, as well as specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0037] Preferably, the branched alkylbenzene sulfonic acid catalyst is removed and then post-treated to obtain the short-carbon alkyl glycoside.

[0038] Preferably, the post-treatment includes filtration, adjusting the pH to 7-8 (for example, 7.1, 7.3, 7.5, 7.7 or 7.9, etc.), dealcoholization, bleaching, and adjusting the solid content.

[0039] Preferably, the pH is adjusted using an alkaline solution.

[0040] Preferably, the alkaline solution comprises sodium hydroxide solution.

[0041] Preferably, the mass percentage of alkali in the alkaline solution is 25-40%, for example, it can be 28%, 30%, 32%, 35% or 38%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0042] Preferably, the dealcoholization method comprises distillation.

[0043] Preferably, the distillation comprises short path molecular distillation.

[0044] Preferably, the bleaching agent comprises hydrogen peroxide.

[0045] Preferably, the post-treatment further comprises adjusting the solid content.

[0046] Preferably, the solid content is adjusted by using water.

[0047] Preferably, the adjusting the solid content includes adjusting the solid content to 50-80%, for example, it can be 55%, 60%, 65%, 70% or 75%, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0048] In a second aspect, the present invention provides a short-carbon alkyl glycoside, which is prepared by the preparation method described in the first aspect.

[0049] In a third aspect, the present invention provides a use of the short-carbon alkyl glycoside as described in the second aspect in bubble-free oil removal and high-pressure spray cleaning.

[0050] Compared with the prior art, the present invention has at least the following beneficial effects:

[0051] (1) The method for preparing short-carbon alkyl glycoside provided by the present invention uses a branched alkylbenzene sulfonic acid compound as a catalyst. After the reaction is completed, the catalyst is adsorbed and removed. In some preferred technical schemes, a glucose homogenization and refinement operation is combined, and the material is slowly fed to obtain a foam-free short-carbon alkyl glycoside. The process is simple, the content of polysaccharide by-products in the product is low, and it is not turbid when diluted with water, which can meet the requirements of industries such as industrial bubble-free oil removal and high-pressure spray cleaning.

[0052] (2) The method for preparing short-chain alkyl glycoside provided by the present invention can reduce the generation of by-products and thus improve the yield of short-chain alkyl glycoside by subjecting alcohol monomers (short-chain alcohols) to a step-by-step mixing reaction, and can also effectively reduce the foaming of the obtained short-chain alkyl glycoside, thereby obtaining a foam-free product. DETAILED DESCRIPTION

[0053] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0054] The materials involved in the following examples are all commercially available products, among which the strong base anion exchange resin adopts HPA-200 strong base anion exchange resin produced by Dongying Hecheng Chemical Technology Co., Ltd.;

[0055] Branched octylbenzene sulfonic acid was purchased from Shandong Yousuo Chemical Technology Co., Ltd. and has the following structure:

[0056] .

[0057] The residual sugar content is tested according to GB / T 19464-2014 standard, and the residual sugar content is less than 0.3%, which is qualified.

[0058] Example 1

[0059] A method for preparing a short carbon alkyl glycoside, the preparation method comprising the following steps:

[0060] (1) In a 1L beaker, add 208g of n-hexanol and 180g of anhydrous glucose (the average volume particle size measured by a particle size analyzer is 271.75μm, and the alcohol and sugar settle to the bottom for about 2 minutes). Turn on the homogenizer and adjust the speed to 20,000 rpm. Homogenize for 10 minutes. The average volume particle size of glucose measured by a particle size analyzer is 46.51μm (it takes about 1.5 hours for the glucose to settle to the bottom when it is still). A mixed solution is obtained.

[0061] (2) In a 1L glass reactor with a water separator and a condenser, 200.8 g of n-hexanol and 1.8 g of branched octylbenzenesulfonic acid catalyst were added, the vacuum was adjusted to 14000 Pa, the temperature was raised to 105° C., and the mixed solution obtained in step (1) was slowly added within 30 minutes. After the addition was completed, the mixture was refluxed for 4 hours. After the vacuum was broken, a sample was taken to measure the residual sugar content of 0.22%. The temperature was lowered to 60° C., 5 g of a strong alkaline anion exchange resin was added, and the mixture was stirred for 1 hour, filtered, and the filtrate was adjusted to pH 7 with a 32% by weight sodium hydroxide solution, and then transferred to a short-range molecular distillation to remove unreacted alcohol. The collected material was bleached with 2wt% hydrogen peroxide, and the solid content was adjusted to 75% with deionized water to obtain 310.2 g of hexyl glycoside aqueous solution with a yield of 88.6%.

[0062] Example 2

[0063] A method for preparing a short carbon alkyl glycoside, the preparation method comprising the following steps:

[0064] (1) Same as Example 1.

[0065] (2) In a 1L glass reactor with a water separator and a condenser, 303 g of n-hexanol and 1.8 g of branched octylbenzenesulfonic acid catalyst were added, the vacuum was adjusted to 16000 Pa, the temperature was raised to 105° C., and the mixed solution obtained in step (1) was slowly added within 30 minutes. After the addition was completed, the mixture was refluxed for 3.67 hours. After the vacuum was broken, a sample was taken to measure the residual sugar content of 0.13%. The temperature was lowered to 70° C., 5 g of a strong alkaline anion exchange resin was added, and the mixture was stirred for 1 hour, filtered, and the filtrate was adjusted to pH 7 with a mass percentage of 32% sodium hydroxide solution, and then transferred to a short-range molecular distillation to remove unreacted alcohol. The collected material was bleached with 2wt% hydrogen peroxide, and the solid content was adjusted to 75% with deionized water to obtain 314.9 g of a hexyl glycoside aqueous solution with a yield of 89.6%.

[0066] Example 3

[0067] A method for preparing a short carbon alkyl glycoside, the preparation method comprising the following steps:

[0068] (1) Same as Example 1.

[0069] (2) In a 1L glass reactor equipped with a water separator and a condenser, 149.7g of n-hexanol and 1.8g of branched octylbenzenesulfonic acid catalyst were added, the vacuum was adjusted to 13500Pa, the temperature was raised to 110°C, and the mixed solution obtained in step (1) was slowly added within 30 minutes. After the addition was complete, the mixture was refluxed for 3.83 hours. After the vacuum was broken, a sample was taken to measure the residual sugar content of 0.15%. The mixture was cooled to 80°C, 5g of a strong alkaline anion exchange resin was added, and the mixture was stirred for 1 hour and filtered. The filtrate was adjusted to pH 7 with a 32% by weight sodium hydroxide solution, and then transferred to a short-range molecular distillation to remove unreacted alcohol. The collected material was bleached with 2wt% hydrogen peroxide, and the solid content was adjusted to 75% with deionized water to obtain 302.5g of a hexyl glycoside aqueous solution with a yield of 88.2%.

[0070] Example 4

[0071] A method for preparing a short carbon alkyl glycoside, the preparation method comprising the following steps:

[0072] (1) Same as Example 1.

[0073] (2) In a 1L glass reactor equipped with a water separator and a condenser, 200.8 g of n-hexanol and 1.5 g of branched octylbenzenesulfonic acid catalyst were added, the vacuum was adjusted to 14000 Pa, the temperature was raised to 105° C., and the mixed solution obtained in step (1) was slowly added within 30 minutes. After the addition was complete, the mixture was refluxed for 4.5 hours. After the vacuum was broken, a sample was taken to measure the residual sugar content of 0.21%. The mixture was cooled to 50° C., 4 g of a strongly basic anion exchange resin was added, and the mixture was stirred for 0.5 hour, filtered, and the filtrate was adjusted to pH 7 with a 32% by weight sodium hydroxide solution, and then transferred to a short-range molecular distillation to remove unreacted alcohol. The collected material was bleached with 2wt% hydrogen peroxide, and the solid content was adjusted to 75% with deionized water to obtain 311.7 g of a hexyl glycoside aqueous solution with a yield of 87.9%.

[0074] Example 5

[0075] A method for preparing a short carbon alkyl glycoside, the preparation method comprising the following steps:

[0076] (1) In a 1L beaker, add 208 g of isooctyl alcohol and 180 g of anhydrous glucose. Turn on the homogenizer and adjust the speed to 20,000 rpm. Homogenize for 10 minutes to obtain a mixed solution.

[0077] (b) In a 1L glass reactor with a water separator and a condenser, 312.8 g of isooctyl alcohol and 2 g of branched octylbenzene sulfonic acid catalyst were added, the vacuum was adjusted to 9000 Pa, the temperature was raised to 110° C., and the mixed solution obtained in step (1) was slowly added over 30 minutes. After the addition was completed, the mixture was refluxed for 5.5 hours. After the vacuum was broken, a sample was taken to measure the residual sugar content of 0.21%. The mixture was cooled to 40° C., 4 g of a strongly basic anion exchange resin was added, and the mixture was stirred for 1.5 hours, filtered, and the filtrate was adjusted to pH 7 with a 32% by weight sodium hydroxide solution, and then transferred to a short-range molecular distillation to remove unreacted alcohol. The collected material was bleached with 2wt% hydrogen peroxide, and the solid content was adjusted to 60% with deionized water to obtain 413.7 g of an isooctyl glycoside aqueous solution with a yield of 79.5%.

[0078] Example 6

[0079] A method for preparing a short carbon alkyl glycoside, the preparation method comprising the following steps:

[0080] (1) Same as Example 5.

[0081] (2) In a 1L glass reactor equipped with a water separator and a condenser, 377.9g of isooctyl alcohol and 2.2g of branched octylbenzene sulfonic acid catalyst were added, the vacuum was adjusted to 9000Pa, the temperature was raised to 100°C, and the mixed solution obtained in step (1) was slowly added within 30 minutes. After the addition was complete, the mixture was refluxed for 5.7 hours. After the vacuum was broken, a sample was taken to measure the residual sugar content of 0.25%. The mixture was cooled to 50°C, 6g of a strong alkaline anion exchange resin was added, and the mixture was stirred for 2 hours. The mixture was filtered, and the filtrate was adjusted to pH 7 with a 32% by weight sodium hydroxide solution, and then transferred to a short-range molecular distillation to remove unreacted alcohol. The collected material was bleached with 2wt% hydrogen peroxide, and the solid content was adjusted to 60% with deionized water to obtain 385.0g of isooctyl glycoside aqueous solution with a yield of 79.8%.

[0082] Example 7

[0083] A method for preparing a short carbon alkyl glycoside, the preparation method comprising the following steps:

[0084] (1) In a 1L beaker, add 208g of n-hexanol and 180g of anhydrous glucose (the volume average particle size measured by a particle size analyzer is 271.75μm, and the alcohol and sugar are allowed to settle to the bottom for about 2 minutes), adjust the speed to 200 rpm, and stir for 10 minutes to obtain a mixed solution.

[0085] (2) In a 1L glass reactor with a water separator and a condenser, 200.8 g of n-hexanol and 1.8 g of branched octylbenzenesulfonic acid catalyst were added, the vacuum was adjusted to 14000 Pa, the temperature was raised to 105° C., and the mixed solution obtained in step (1) was slowly added within 30 minutes. After the addition was completed, the mixture was refluxed for 4 hours. After the vacuum was broken, a sample was taken to measure the residual sugar content of 1.58%. The reaction was continued for 1 hour, and the residual sugar content was 0.29%. The temperature was lowered to 60° C., 5 g of a strong alkaline anion exchange resin was added, and the mixture was stirred for 1 hour, filtered, and the filtrate was adjusted to pH 7 with a 32% by weight sodium hydroxide solution, and then transferred to a short-range molecular distillation to remove unreacted alcohol. The collected material was bleached with 2wt% hydrogen peroxide, and the solid content was adjusted to 75% with deionized water to obtain 313.7 g of hexyl glycoside aqueous solution with a yield of 87.7%.

[0086] Example 8

[0087] A method for preparing a short carbon alkyl glycoside, the preparation method comprising the following steps:

[0088] (1) In a 1L beaker, add 208g of n-hexanol and 180g of anhydrous glucose (the volume average particle size measured by a particle size analyzer is 271.75μm). Turn on the homogenizer and adjust the speed to 20,000 rpm. Homogenize for 5 minutes. The volume average particle size of glucose measured by a particle size analyzer is 95.45μm. A mixed solution is obtained.

[0089] (2) In a 1L glass reactor equipped with a water separator and a condenser, 200.8g of n-hexanol and 1.8g of branched octylbenzenesulfonic acid catalyst were added, the vacuum was adjusted to 14000Pa, the temperature was raised to 105°C, and the mixed solution obtained in step (1) was slowly added within 30 minutes. After the addition was completed, the mixture was refluxed for 4.5 hours. After the vacuum was broken, a sample was taken to measure the residual sugar content of 0.26%. The mixture was cooled to 60°C, 5g of a strong alkaline anion exchange resin was added, and the mixture was stirred for 1 hour, filtered, and the filtrate was adjusted to pH 7 with a 32% by weight sodium hydroxide solution, and then transferred to a short-range molecular distillation to remove unreacted alcohol. The collected material was bleached with 2wt% hydrogen peroxide, and the solid content was adjusted to 75% with deionized water to obtain 309.4g of hexyl alkyl glycoside aqueous solution with a yield of 88.3%.

[0090] Example 9

[0091] A method for preparing a short carbon alkyl glycoside, the preparation method comprising the following steps:

[0092] (1) Same as Example 7.

[0093] (2) In a 1L glass reactor equipped with a water separator and a condenser, 200.8g of n-hexanol and 2.6g of branched octylbenzenesulfonic acid catalyst were added, the vacuum was adjusted to 14000Pa, the temperature was raised to 105°C, and the mixed solution obtained in step (1) was slowly added within 30 minutes. After the addition was complete, the mixture was refluxed for 3.92 hours. After the vacuum was broken, a sample was taken to measure the residual sugar content of 0.18%. The mixture was cooled to 60°C, 5g of a strong alkaline anion exchange resin was added, and the mixture was stirred for 1 hour, filtered, and the filtrate was adjusted to pH 7 with a 32% by weight sodium hydroxide solution, and then transferred to a short-range molecular distillation to remove unreacted alcohol. The collected material was bleached with 2wt% hydrogen peroxide, and the solid content was adjusted to 75% with deionized water to obtain 308.2g of hexyl glycoside aqueous solution with a yield of 86.8%.

[0094] Comparative Example 1

[0095] A method for preparing short-carbon alkyl glycoside, which differs from Example 1 only in that no strong basic anion exchange resin is added in step (2), and other materials, amounts and operating steps are the same as those in Example 1, to obtain 310.9 g of hexyl glycoside aqueous solution with a yield of 88.5%.

[0096] Comparative Example 2

[0097] A method for preparing short-carbon alkyl glycoside, which differs from Example 5 only in that no strong basic anion exchange resin is added in step (2), and other materials, amounts and operating steps are the same as those in Example 5, to obtain 414.5 g of isooctyl glycoside aqueous solution with a yield of 79.9%.

[0098] Comparative Example 3

[0099] A method for preparing a short carbon alkyl glycoside, the preparation method comprising the following steps:

[0100] In a 1L glass reactor with a water separator and a condenser, 408.8 grams of n-hexanol, 180 grams of anhydrous glucose and 1.8 grams of branched octylbenzenesulfonic acid catalyst were added, the vacuum was adjusted to 14000Pa, the temperature was raised to 105°C, and the reaction was refluxed for 4 hours. After breaking the vacuum, the residual sugar was sampled and measured to be 1.56%. The temperature was lowered to 60°C, 5 grams of strongly basic anion exchange resin was added, and after stirring for 1 hour, the mixture was filtered. The filtrate was adjusted to pH 7 with a mass percentage of 32% sodium hydroxide solution, and then transferred to a short-range molecular distillation to remove unreacted alcohol. The collected material was bleached with 2wt% hydrogen peroxide, and the solid content was adjusted to 75% with deionized water to obtain 310.6 grams of hexyl glycoside aqueous solution with a yield of 84.0%.

[0101] Comparative Example 4

[0102] A method for preparing a short carbon alkyl glycoside, the preparation method comprising the following steps:

[0103] In a 1L glass reactor with a water separator and a condenser, 520.8 grams of isooctyl alcohol, 180 grams of anhydrous glucose and 2 grams of branched octylbenzenesulfonic acid catalyst were added, the vacuum was adjusted to 9000Pa, the temperature was raised to 110°C, and the reaction was refluxed for 5.5 hours. After breaking the vacuum, the residual sugar was sampled and measured to be 1.89%. The temperature was lowered to 40°C, 4 grams of strongly basic anion exchange resin were added, and the mixture was stirred for 1.5 hours, filtered, and the filtrate was adjusted to pH 7 with a mass percentage of 32% sodium hydroxide solution, and then transferred to a short-range molecular distillation to remove unreacted alcohol. The collected material was bleached with 2wt% hydrogen peroxide, and the solid content was adjusted to 60% with deionized water to obtain 407.1 grams of isooctyl glycoside aqueous solution with a yield of 73.9%.

[0104] Comparative Example 5

[0105] A method for preparing a short-carbon alkyl glycoside, which differs from Example 1 only in that the branched octylbenzenesulfonic acid catalyst is replaced by an equal-mass p-toluenesulfonic acid catalyst. At this time, the reflux reaction is carried out for 4 hours, and the residual sugar is only 0.12% after sampling after breaking the air. Therefore, the reflux is no longer continued, and the temperature is lowered for subsequent reactions. Other materials, dosages and operating steps are the same as those in Example 1. The solid content is adjusted to 75% with deionized water to obtain 303.2 grams of hexyl glycoside aqueous solution, and the yield is 87.3%.

[0106] Comparative Example 6

[0107] A method for preparing a short-carbon alkyl glycoside, which differs from Example 1 only in that the branched octylbenzenesulfonic acid catalyst is replaced with an equal mass of dodecylbenzenesulfonic acid catalyst, and other materials, amounts and operating steps are the same as those in Example 1. The solid content is adjusted to 75% with deionized water to obtain 309.6 grams of hexyl glycoside aqueous solution, and the yield is 88.3%.

[0108] Comparative Example 7

[0109] A method for preparing a short-carbon alkyl glycoside, which differs from Example 5 only in that the branched octylbenzenesulfonic acid catalyst is replaced by an equal mass of p-toluenesulfonic acid catalyst. At this time, the reflux reaction is carried out for 4.5 hours, and the residual sugar is only 0.05% after sampling after breaking the air. Therefore, the reflux is no longer continued, and the temperature is lowered for subsequent reactions. Other materials, dosages and operating steps are the same as those in Example 1. The solid content is adjusted to 60% with deionized water to obtain 407.6 grams of isooctyl glycoside aqueous solution, and the yield is 78.8%.

[0110] Comparative Example 8

[0111] A method for preparing a short-carbon alkyl glycoside, which differs from Example 5 only in that the branched octylbenzenesulfonic acid catalyst is replaced with an equal mass of dodecylbenzenesulfonic acid catalyst, and other materials, amounts and operating steps are the same as those in Example 5. The solid content is adjusted to 60% with deionized water to obtain 414.8 grams of isooctyl glycoside aqueous solution, and the yield is 79.7%.

[0112] The short carbon alkyl glycoside products of Examples 1-9 and Comparative Examples 1-8 were tested as follows:

[0113] (1) Glucose conversion rate

[0114] According to formula (1), the ratio of actual glucose conversion to raw material input is calculated by the residual sugar in the product.

[0115]

[0116] Among them, m 1 is the mass of glucose feed, m 2 It is the mass of crude glycosides before dealcoholization (i.e. “mass of glucose feed + mass of short-chain alcohol feed + mass of catalyst feed - mass of generated water”).

[0117] (2) Yield

[0118] According to the test method for surfactant detergents in GB / T 13173-2008, alkyl glycosides were extracted with ethanol, filtered and separated, and the ethanol-soluble matter and the insoluble matter in the ethanol-soluble matter were quantified. The content of active matter in alkyl glycosides was calculated by subtracting the content of insoluble matter in the ethanol-soluble matter from the content of ethanol-soluble matter, and then the yield was calculated.

[0119] (3) Polysaccharide content

[0120] With reference to the literature “Liang Meng, Wang Fengshou, Yao Chenzhi. Determination of polysaccharides in alkyl glycosides by reversed-phase high performance liquid chromatography [J], 2014, 50(4)”, the polysaccharide content in alkyl glycosides was determined by high performance liquid chromatography.

[0121] (4) Average degree of polymerization

[0122] Tested according to GB / T 19464-2014.

[0123] (5) Foam generation

[0124] The foam performance of the alkyl polyglycoside of the present invention is tested according to the improved Ross-Miles method, GB / T 7462-94, and the foam volume (mL) at 0 seconds, 30 seconds, 3 minutes and 5 minutes is recorded.

[0125] (6) Dilution turbidity range

[0126] In a 500 mL beaker, add 5 g of the prepared short-carbon alkyl glycoside, and slowly add deionized water while stirring. Calculate the mass percentage of the short-carbon alkyl glycoside when the solution becomes turbid.

[0127] The test results are summarized in Table 1.

[0128] Table 1

[0129]

[0130] The test results show that the present invention adopts a specific type of catalyst combined with a specific process method to obtain a short-chain alkyl glycoside that is a foam-free surfactant, has no turbidity range when diluted, has a short overall process synthesis time, a high glucose conversion rate, low residual sugar, and few by-products, and can meet the requirements of industries such as industrial foam-free oil removal and high-pressure spray cleaning.

[0131] By comparing Examples 1-9, it can be seen that the present invention uses branched alkylbenzene sulfonic acid as a catalyst in conjunction with a glucose homogenization and refinement operation and a specific process of slowly adding a sugar alcohol homogenized liquid. The smaller the glucose particle size, the easier it is for the reaction raw material to form a stable emulsion form, the larger the solid-liquid contact surface of the sugar alcohol, the higher the probability of intermolecular collision, the faster the reaction, and the fewer by-products. At the same time, the mixed solution obtained in step (1) is slowly added, the alcohol-sugar ratio is higher during the reaction, the reaction speed is faster, and the by-product content in the product is lower. More catalyst is added, which helps to shorten the reaction time, but the by-product polysaccharide content in the product will increase. By comparing Examples 1 and 5 with Comparative Examples 1 and 2, it can be seen that if the ion exchange resin is not treated after synthesis and the catalyst is not separated and removed in time, the obtained short-carbon alkyl glycoside will have certain foam; by comparing Example 1 with Example 7 and Example 8, it can be seen that the method of homogenizing glucose in the present invention can significantly shorten the reaction time while ensuring that a foam-free product is obtained, and the by-products are reduced. Further, by comparing Examples 1 and 5 with Comparative Examples 3 and 4, it can be seen that the present invention can significantly shorten the reaction time while ensuring that a foam-free product is obtained by homogenizing glucose and then mixing alcohol monomers in steps, and the by-products are less, which can significantly improve the yield of glucose; by comparing Examples 1 and 5 with Comparative Examples 5-8, it can be seen that the present invention uses a specific branched alkylbenzene sulfonic acid catalyst to obtain a foam-free short-carbon alkyl glycoside product while preventing the product from having a turbid range when diluted, and further reducing the amount of polysaccharide by-products.

[0132] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a foam-free short-carbon alkyl glycoside, characterized in that: The preparation method comprises the following steps: (1) mixing the first portion of the short-chain alcohol with glucose to obtain a mixed solution; (2) mixing the mixed solution obtained in step (1) with the second part of the short-chain alcohol and the branched alkylbenzene sulfonic acid catalyst, reacting the mixture, removing the branched alkylbenzene sulfonic acid catalyst, and obtaining the foam-free short-chain alkyl glycoside; The short-chain alcohols in the first part of short-chain alcohols and the second part of short-chain alcohols are C4-C10 straight-chain or branched-chain alcohols; The mass ratio of the first part of short carbon chain alcohol to glucose is (1-4): 1; The molar ratio of the total molar amount of the first part of the short-chain alcohol and the second part of the short-chain alcohol to glucose is (1-10):1; The branched alkylbenzene sulfonic acid catalyst is branched octylbenzene sulfonic acid, and the branched octylbenzene sulfonic acid has the following structure: ； The method for removing the branched alkylbenzene sulfonic acid catalyst is to use a strong basic anion exchange resin for adsorption.

2. The preparation method according to claim 1, characterized in that: The short carbon chain alcohol is any one of n-hexanol, n-heptanol or isooctyl alcohol, or a combination of at least two of them.

3. The preparation method according to claim 1, characterized in that: The mixing method is homogenization; The homogenizing speed is 5000-30000 rpm; The homogenization time is 1-30min; The volume average particle size of the material in the mixed liquid is 1-100 μm.

4. The preparation method according to claim 1, characterized in that: The mass ratio of the glucose to the branched alkylbenzene sulfonic acid catalyst is 1:(0.001-0.1).

5. The preparation method according to claim 1, characterized in that: The mixing pressure in step (2) is 100-30000Pa; The mixing temperature in step (2) is 60-130°C; The mixing time in step (2) is 0.5-2h.

6. The preparation method according to claim 1, characterized in that: The reaction time is 2-10h; The reaction temperature is 60-130°C.

7. The preparation method according to claim 1, characterized in that: The adsorption temperature is 30-95°C; The adsorption time is 10-300min; The mass ratio of the strong basic anion exchange resin to the branched alkylbenzene sulfonic acid catalyst is (1-5):1; The particle size of the strong basic anion exchange resin is 0.32-1.3 mm; The exchange capacity of the strongly basic anion exchange resin is ≥1 mol / L.

8. The preparation method according to claim 1, characterized in that: After removing the branched alkylbenzene sulfonic acid catalyst, post-treatment is performed to obtain the short-carbon alkyl glycoside; The post-treatment includes filtration, adjusting the pH to 7-8, dealcoholization and bleaching.

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