CN101412706B - Novel method for preparing 1,3-dihydroxy acetone from glycerol - Google Patents

Abstract

The invention discloses a new method for preparing 1,3-dihydroxyacetone from glycerin. The preparation method comprises the following steps: (1) acetalization reaction: in the presence of a water-carrying agent, glycerol and benzaldehyde are reacted in an acid catalyst Acetalization reaction occurs under the action of A to obtain the glycerol benzaldehyde acetal ether of structure as shown in formula (I); (2) oxidation reaction: the glycerol benzaldehyde acetal ether of gained is oxidized under the action of oxidizing agent in organic solvent and obtains 5-carbonyl-2-phenyl-1,3-dioxane whose structure is shown in formula (II); (3) hydrolysis reaction: the obtained 5-carbonyl-2-phenyl-1,3-di The oxane is hydrolyzed in the presence of an acid catalyst B to prepare a 1,3-dihydroxyacetone dimer with the structure shown in formula (III). The synthesis route of the present invention uses glycerol as a raw material, the selectivity and yield are higher than those of the direct oxidation method, the target product is easy to separate, and the product purity can reach 99%. Compared with the prior art, the synthesis route of the present invention has relatively high Great market competitiveness.

Description

A new method for preparing 1,3-dihydroxyacetone from glycerol

(1) Technical field

The invention relates to a preparation method of 1,3-dihydroxyacetone.

(2) Background technology

In recent years, with the continuous expansion of oleochemicals, especially biodiesel, the supply of its by-product glycerin has been seriously oversupplied, and the price has dropped sharply. The development of downstream products using glycerin as raw material can not only solve the problem of excess glycerin, but also Can reduce the production cost of biodiesel. 1,3-Dihydroxyacetone (DHA, dihydroxyacetone) is an important pharmaceutical intermediate, chemical raw material, food additive, and component of cosmetic sunscreens. It can also be used as an antiviral agent. For example, in egg embryo culture, it can kill 51% to 100% of fowl plague virus; it can also be used for antiseptic preservation of fruits and vegetables, aquatic products, and meat products; there are still many other uses in active development research and development.

At present, the relatively mature industrial preparation method of 1,3-dihydroxyacetone is mainly the enzymatic method (J.Ferment Technol, 1979,57 (3): 227), that is, glycerol is oxidized to 1,3-dihydroxyacetone with glycerol dehydrogenase Dihydroxyacetone. However, the existence of fungi limits the concentration range of glycerol, making it difficult to increase the yield of the enzymatic method, and due to the influence of many by-products, the entire post-treatment process becomes complicated, time-consuming and energy-consuming, and the production cost is high. Due to the wide application of DHA, the large market capacity, and the large excess of glycerol as a by-product of biodiesel, it is of great significance to study a new method for preparing DHA from glycerol with high yield and convenient purification.

There are many patents and literature reports on the conversion of glycerol into dihydroxyacetone by chemical synthesis abroad, but the main method is the direct catalytic oxidation method to prepare dihydroxyacetone. Since glycerol is a polyhydroxy compound, the conversion rate of glycerol and the yield of dihydroxyacetone are relatively low when the direct oxidation route is adopted. A study published by Kimura.etal showed that when glycerin was oxidized, adding Bi to the Pt catalyst could greatly improve the selectivity to secondary alcohols. When the catalyst was 1% Bi-5% Pt/C, a batch of reactions The yield of dihydroxyacetone was 20% (Appl. Catal. A, 1993, 96: 217). When the catalyst is 0.6% Bi-3% Pt supported on activated carbon, the conversion rate is 40% in a mixed bed reaction, and the yield of DHA is 30% (German patent, DE4228487). Under acidic conditions, and adding a certain amount of auxiliary agent, using Pt catalyst, the conversion rate of glycerol can reach 70%, but the maximum yield of glycerol conversion to form dihydroxyacetone is only 37% (Catalysis Today, 2000, 57: 127). This is the data with the highest yield of dihydroxyacetone prepared from glycerin oxidation so far. In the domestically reported direct catalytic oxidation of glycerol, the catalyst is 9% Pt-5% Bi/C, the reaction temperature is 55°C, and the reaction time is 50 hours. The selectivity of DHA is only 40.2%, and the conversion rate of glycerol is 81.6%. The yield is only 32.8% (Journal of Hainan Normal University (Natural Science Edition), 2007, 20(3)). It can be seen that the direct oxidation of glycerol is difficult to change the shortcomings of long reaction time and poor selectivity only by improving the catalyst.

(3) Contents of the invention

The technical problem to be solved by the present invention is to provide a method for preparing 1,3-dihydroxyacetone by using glycerol as a raw material. The preparation method has high conversion rate, good selectivity and simple product separation and purification.

In order to solve the problems of the technologies described above, the present invention adopts the following technical solutions:

A kind of preparation method of 1,3-dihydroxyacetone, described preparation method is as follows: (1) acetalization reaction: in the presence of water-carrying agent, glycerin and benzaldehyde take place acetalization reaction under the action of acid catalyst A to obtain The structure is as the glycerol benzaldehyde acetal ether shown in formula (I); (2) oxidation reaction: the glycerol benzaldehyde acetal ether of gained is oxidized under the action of oxidizing agent to obtain the structure such as the 5-carbonyl group shown in formula (II) 2-phenyl-1,3-dioxane; (3) hydrolysis reaction: the obtained 5-carbonyl-2-phenyl-1,3-dioxane is hydrolyzed in the presence of acid catalyst B to produce The 1,3-dihydroxyacetone dimer with the structure shown in formula (III) is obtained.

The reaction equation is as follows:

Each reaction step of the above preparation method will be described in detail below.

The acetalization reaction described in step (1) of the present invention can specifically be carried out according to the following steps: add glycerin, benzaldehyde, acid catalyst A and water-carrying agent into the reaction vessel, heat up to 100-130°C under stirring and react 1-6 hour, after the reaction finishes, the acetal reaction solution obtains the glycerol benzaldehyde acetal ether of structure as shown in formula (I) through separation and purification; The dosage of the acid catalyst A is 1-10% of the glycerin weight.

Further, the acid catalyst A used in the acetalization reaction can be a liquid acid or a solid acid, preferably concentrated sulfuric acid, p-toluenesulfonic acid or a strong acid cation exchange resin, and the strong acid cation exchange resin can be selected from CD550 , D072 and other strong acid cation exchange resins.

The water carrier used in the acetalization reaction is preferably benzene or toluene, more preferably benzene. The volume dosage of the water-carrying agent is 3 to 5 times the volume of glycerin.

The separation and purification method described in the acetalization reaction can be carried out as follows: after the acetal reaction liquid is washed, dried, and the water-carrying agent is recovered, it is placed in a mixed solution of benzene and petroleum ether at -9.0～-25.0°C Crystallization to obtain glycerol benzaldehyde acetal ether.

In the above separation and purification steps, washing, drying, recovery of the water-carrying agent, and crystallization are all routine operations. Preferably, the above separation and purification method is recommended to be carried out in accordance with the following steps: the acetal reaction solution is washed with 10% NaOH solution successively, and the Wash with ionic water, then dry with anhydrous potassium carbonate, recover the water-carrying agent by distillation under reduced pressure, add a mixed solution of benzene and petroleum ether (volume ratio 1:1), freeze to -9.0～-25.0°C, after 3 to 4 hours , suction filtration, washed with a cold mixed solution of benzene and petroleum ether (volume ratio 1:1) to obtain the primary product, and then recrystallized to obtain glycerol benzaldehyde acetal ether with a purity close to 100%. The recovered water-carrying agent and the crystallized mother liquor obtained by crystallization can be reused in the acetal reaction for recycling, thereby improving the utilization rate of raw materials and reducing costs.

The oxidation reaction described in the step (2) of the present invention is specifically carried out according to the following steps: adding glycerol benzaldehyde acetal ether to an organic solvent containing an oxidizing agent, and reacting at room temperature for 0.5 to 10 hours. After the reaction, the oxidized reaction solution passes through Separation and purification yielded 5-carbonyl-2-phenyl-1,3-dioxane with the structure shown in formula (II).

Further, the oxidizing agent used in the above oxidation reaction can be other metal oxide oxidizing agents such as potassium permanganate, including Collins reagent (chromium trioxide bipyridine), PCC reagent (chromium trioxide pyridine hydrochloride), DCC reagent (dipyridine hydrochloride Methylamine chromium trioxide); Oxidant also can be air or oxygen, should add catalyzer at this moment in the system, and pass into enough air or oxygen, catalyzer can be TEMPO (2,2,6,6-tetramethylpiperene Pyridine-1-oxygen free radical), NaNO ₂ and FeCl ₃ , the molar dosages of TEMPO, NaNO ₂ and _FeCl are respectively 0.1～10%, 0.3～10% and 0.3～10% of the molar weight of glycerol benzaldehyde acetal ether . The oxidizing agent is preferably Collins reagent, PCC reagent or DCC reagent, and its dosage is 2-5 times of the weight of glycerol benzaldehyde acetal ether.

Collins reagent, PCC reagent and DCC reagent used in the present invention can be prepared according to the following method:

(1) Collins reagent (chromium trioxide dipyridine)

Under cooling in an ice bath, slowly add chromium trioxide to excess pyridine, and control the temperature below 20°C (note: never add pyridine to chromium trioxide, otherwise it will cause danger due to violent exotherm), Under continuous stirring, yellow pyridine chromium oxide precipitates will be produced. Continue stirring, the yellow precipitates will gradually transform into dark red granular crystals. After filtering and washing with petroleum ether, Collins reagent was obtained after drying.

(2) PCC reagent (chromium trioxide pyridine hydrochloride)

Quickly add chromium trioxide to 6mol/L hydrochloric acid (adding while stirring), after 5 minutes, cool the homogeneous solution to 0°C to obtain a reddish-brown liquid, filter under normal pressure to remove insoluble matter, then add pyridine within 10 minutes, With the addition of pyridine, yellow solids gradually precipitated. After the pyridine was added dropwise, it was cooled to 0°C again to obtain an orange solid. The product was collected by filtration with a sand core funnel, dried in a vacuum dryer for 1 hour, and then After drying for 48 hours at room temperature in a desiccator equipped with phosphorus pentoxide, the PCC reagent was obtained.

(3) DCC reagent (dimethylamine chromium trioxide hydrochloride)

Add chromium trioxide to a beaker of deionized water. After being dissolved, an equimolar amount of dimethylamine hydrochloride was added under stirring. Heat in a water bath until the solids dissolve and then keep warm for 10 to 15 minutes. After cooling, filter under reduced pressure, wash once with ice water, and dry to obtain DCC reagent.

Still further, the organic solvent used in the above oxidation reaction is preferably dichloromethane, chloroform, cyclohexane or N,N-dimethylformamide. The mass dosage of the organic solvent is 10-30 times of the weight of the glycerol benzaldehyde acetal ether.

The separation and purification method described in the oxidation reaction is carried out as follows: after oxidation, the reaction liquid is washed, dried, and distilled to recover the organic solvent, and then recrystallized to obtain 5-carbonyl-2-phenyl-1,3-dioxane hexane.

In the above separation and purification steps, washing, drying, distillation, and recrystallization are all routine operations. Preferably, the above separation and purification are recommended to be carried out in accordance with the following steps: wash the oxidized reaction solution with saturated saline, and then wash it with anhydrous magnesium sulfate After drying, the organic solvent was recovered by atmospheric distillation, and the remaining substance was recrystallized with ether to obtain high-purity 5-carbonyl-2-phenyl-1,3-dioxane.

The hydrolysis reaction described in step (3) of the present invention is specifically carried out according to the following steps: 5-carbonyl-2-phenyl-1,3-dioxane, acid catalyst B and deionized water are respectively added to the reaction vessel , heated to 50-90°C under stirring, and reacted for 2-10 hours. After the reaction was completed, 1,3-dihydroxyacetone dimer was obtained by separation and purification; the amount of the acid catalyst B was 5-carbonyl-2-benzene 1 to 4 times the weight of the base-1,3-dioxane.

Further, the acid catalyst B used in the hydrolysis reaction can be selected from commonly used catalysts in general hydrolysis reactions, such as p-toluenesulfonic acid, sulfuric acid, hydrochloric acid, the present invention recommends the use of solid acid catalysts, and the solid acid catalyst is preferably CD550 strong acid Type cation exchange resin, D072 strong acid type cation exchange resin or D061 strong acid type cation exchange resin.

The amount of water added in the above hydrolysis reaction is 10 to 30 times the weight of 5-carbonyl-2-phenyl-1,3-dioxane.

The separation and purification method described in the hydrolysis reaction adopts the methods commonly used in this technical field. For example, when using a solid acid catalyst, the product can be separated and purified according to the following method: after the hydrolysis reaction is completed, the solid acid catalyst is removed by filtration, and the filtrate is used. After washing with a small amount of n-hexane, add n-butanol to remove water through vacuum azeotropic distillation at a temperature lower than 40°C. After stirring the crystals at room temperature for about 16-20 hours, filter and rinse the crystals with acetone at 0°C, and dry them at low temperature. Dry at 40°C to obtain 1,3-dihydroxyacetone dimer. The solid acid catalyst obtained by filtration can be reused.

In the present invention, thin layer chromatography can be used to detect the hydrolysis of 5-carbonyl-2-phenyl-1,3-dioxane, and the hydrolysis reaction process detects the hydrolysis every 1 hour, and uses a silica gel plate thin layer According to the analysis, the solvent system is cyclohexane:ethyl acetate=1:1,5-carbonyl-2-phenyl-1,3-dioxane, and the migration ratio R _f =0.67.

In addition, the present invention marks the acid catalysts used in the acetalization reaction and the hydrolysis reaction as A and B respectively, the purpose of which is to distinguish different steps, and it does not mean that they cannot be the same catalyst.

Compared with prior art, the beneficial effect of the present invention is:

1. The synthesis route of the present invention uses glycerol as a raw material, the selectivity and yield are higher than those of the direct oxidation method, the target product is easy to separate, and the product purity can reach 99%;

2. The solid acid catalyst used in the hydrolysis reaction of the present invention is easy to separate from the product, easy to purify, simple in process, and the solid acid catalyst can be reused or used continuously.

Therefore, compared with the prior art, the route for preparing 1,3-dihydroxyacetone from glycerol described in the present invention has greater market competitiveness.

(4) Description of drawings:

Figure 1 is the H NMR spectrum of 1,3-dihydroxyacetone dimer, with chloroform-d (D, 99.8%)+TMS0.03% (v/v) as the solvent.

(5) Specific implementation plan

The technical scheme of the present invention will be further described below with specific examples, but protection scope of the present invention is not limited to this:

Embodiment one

Step (1): In a 250ml round bottom flask equipped with a condenser and a water separator, add 0.6g of p-toluenesulfonic acid, 58.0g of glycerol, 61.0g of benzaldehyde, and 100ml of benzene, heat and stir, and condense to reflux. The reaction temperature was controlled at 130° C., and the reaction time was 2 hours. The reaction solution was washed with water, dried with anhydrous potassium carbonate, distilled under reduced pressure (recovering benzene), and then crystallized in a mixed solution of benzene and petroleum ether (volume ratio 1:1) at -10°C to obtain 12.4 g of glycerin benzaldehyde acetal ether. Its yield was 12.3%. The recovered benzene and acetal crystallization mother liquor are reserved for later use.

Step (2): Slowly add 1 mol of chromium trioxide to 2 mol of pyridine, and control the reaction temperature below 40°C. Under continuous stirring, yellow pyridine chromium oxide precipitates will be produced. Continue stirring, and the yellow precipitates will gradually transform into dark red particles. crystallization. After filtering and washing with petroleum ether, Collins reagent (chromium trioxide dipyridine) was obtained after drying. 250ml of dichloromethane and 60.0g of Collins reagent were successively added into a three-necked flask equipped with a condenser, and then 12.4g of glycerol benzaldehyde acetal was added. After reacting at room temperature for 1.5 hours, decant the upper layer solution, wash the residue at the bottom with dichloromethane, combine the decanted liquid and the washing liquid, wash with saturated brine, dry over anhydrous magnesium sulfate, and recover distilled water under normal pressure. Chloromethane. After distillation, the solid was recrystallized with diethyl ether and vacuum-dried at room temperature to obtain 10.1 g of 5-carbonyl-2-phenyl-1,3-dioxane with a yield of 81.5%.

Step (3): Wash the CD550 strong-acid cation exchange resin with deionized water, soak it in deionized water for 24 hours, take it out and dry it for later use. Add 10.1g of 5-carbonyl-2-phenyl-1,3-dioxane and 100ml of deionized water into a three-necked flask equipped with a condenser, heat and stir to 80°C, and then add 30.0g of CD550 after dissolving Strong-acid cation exchange resin, using thin-layer chromatography to track and detect the reaction end point. After the reaction was completed, the catalyst was removed by suction filtration under reduced pressure, the filtrate was washed with n-hexane, then n-butanol was added, and water was removed by vacuum azeotropic distillation at 40°C. The crystals were stirred at room temperature, filtered and washed with acetone at 0°C, and dried at a temperature lower than 40°C to obtain 4.9 g of 1,3-dihydroxyacetone dimer with a yield of 97.0%. The chemical structure of the product was confirmed by HNMR analysis, and the color development of the phosphomolybdic acid solution was a positive reaction.

Embodiment two

Step (1): In a 250ml round bottom flask equipped with a condenser tube and a water separator, add 1ml of 98% sulfuric acid, 58g of glycerin, 61g of benzaldehyde (about 6% excess benzaldehyde) and 100ml of acetal crystallization mother liquor, heat and stir , condensed and refluxed, the reaction temperature was 130° C., and the reaction time was 6 hours. After the reaction is completed, the reaction solution is washed with water, dried with anhydrous potassium carbonate, and distilled under reduced pressure (recovering benzene), and then crystallized in a mixed solution of benzene and petroleum ether (1:1) at -10°C to obtain glycerol benzaldehyde acetal ether 21.6 g, its yield is 21.4%. The recovered benzene and crystallization mother liquor are reserved for later use.

Step (2): Quickly add 100 g of chromium trioxide to 6 mol/L hydrochloric acid (containing 1.1 mol HCl) (adding while stirring), after 5 minutes, cool the homogeneous solution to 0°C to obtain a reddish-brown liquid, which is removed by filtration under normal pressure Insoluble matter, then add 79.1g of pyridine within 10min, along with the addition of pyridine, gradually a yellow solid precipitates out, after adding pyridine dropwise, re-cool to 0°C to obtain an orange solid, collect the product by filtration with a sand core funnel, and After the product was dried in a vacuum desiccator for 1 hour, it was placed in a desiccator equipped with phosphorus pentoxide and dried for 48 hours at room temperature to obtain 180 g of a constant weight product, i.e. PCC reagent (pyridine chromium trioxide hydrochloride). 250ml of dichloromethane and 45.0g of PCC reagent were successively added into a three-necked flask equipped with a condenser, and then 21.6g of glycerol benzaldehyde acetal was added. After reacting at room temperature for 4 hours, decant the upper layer solution, wash the residue at the bottom with dichloromethane, combine the decanted liquid and the washing liquid, wash with saturated brine, dry over anhydrous magnesium sulfate, and recover distilled water by atmospheric distillation. Chloromethane; the distilled solid was recrystallized with ether, and vacuum-dried at room temperature to obtain 5-carbonyl-2-phenyl-1,3-dioxane with a yield of 85.2%.

Step (3): Wash the D072 strong-acid cation exchange resin with deionized water, soak it in deionized water for 24 hours, take it out and dry it for later use. Add 18.4g of 5-carbonyl-2-phenyl-1,3-dioxane and 100ml of deionized water into a three-necked flask equipped with a condenser, heat and stir to 90°C, and then add 40.0g of D072 strong acid after dissolving Type cation exchange resin, using thin-layer chromatography to track and detect the reaction end point. After the reaction was completed, the catalyst was removed by suction filtration under reduced pressure, the filtrate was washed with n-hexane, then n-butanol was added, and water was removed by vacuum azeotropic distillation at 40°C. Stir the crystals at room temperature for about 24 hours, filter and wash the crystals with acetone at 0°C, and dry at a temperature lower than 40°C to obtain 1,3-dihydroxyacetone dimer with a yield of 97.8%. The chemical structure of the product was confirmed by HNMR analysis, and the color development of the phosphomolybdic acid solution was a positive reaction.

Embodiment three

Step (1): in the 250ml round-bottomed flask that condenser tube, water separator are housed, add D072 strong acid type cation exchange resin 6g, glycerin 58.0g, benzaldehyde 61.0g (benzaldehyde is excessive about 6%), benzene 100ml, Heat and stir, condense and reflux, and the water produced by the reaction and the entrainer benzene are azeotropically distilled out. The reaction temperature was controlled at 110° C., and the reaction time was 6 hours. After the reaction was completed, the reaction solution was washed with water, dried with anhydrous potassium carbonate, and distilled under reduced pressure (recovering benzene) to obtain 18.0 g of glycerol benzaldehyde acetal ether in a mixed solution of benzene and petroleum ether (1:1) at -10°C , and its yield was 17.9%. The recovered benzene and acetal crystallization mother liquor are reserved for later use.

Step (2): Add 50 g (0.5 mol) of chromium trioxide to a beaker filled with 20 mL of water. After being dissolved, add 40.8 g (0.5 mol) of dimethylamine hydrochloride under stirring. Heat in a water bath until the solids dissolve and then keep warm for 10 to 15 minutes. After cooling, filter under reduced pressure, wash once with ice water, and dry to obtain 70 g of orange-red crystals, that is, DCC reagent (dimethylamine chromium trioxide hydrochloride). 250ml of dichloromethane and 45.0g of DCC reagent were successively added into a three-necked flask equipped with a condenser, and then 18.0g of glycerol benzaldehyde acetal was added. After reacting at room temperature for 6 hours, decant the upper layer solution, wash the residue at the bottom with dichloromethane, combine the decanted liquid and the washing liquid, wash with saturated brine, dry over anhydrous magnesium sulfate, and recover distilled water under normal pressure. Chloromethane; recrystallize the distilled solid with ether, and vacuum dry at room temperature to obtain 15.3 g of 5-carbonyl-2-phenyl-1,3-dioxane with a yield of 85.0%.

Step (3): Wash the D061 strong-acid cation exchange resin with deionized water, soak it in deionized water for 24 hours, take it out and dry it for later use. Add 15.3g of 5-carbonyl-2-phenyl-1,3-dioxane and 100ml of deionized water into a three-necked flask equipped with a condenser, heat and stir to 80°C, and then add 35.0g of D061 after dissolving Strong-acid cation exchange resin, using thin-layer chromatography to track and detect the reaction end point. After the reaction was completed, the catalyst was removed by suction filtration under reduced pressure, the filtrate was washed with n-hexane, then n-butanol was added, and water was removed by vacuum azeotropic distillation at 40°C. Stir the crystals at room temperature for about 24 hours, filter and wash the crystals with acetone at 0°C, and dry at a temperature lower than 40°C to obtain 7.5 g of 1,3-dihydroxyacetone dimer with a yield of 98.0%. The chemical structure of the product was confirmed by HNMR analysis, and the color development of the phosphomolybdic acid solution was a positive reaction.

Embodiment four

Step (1): In a 250ml round bottom flask equipped with a condenser and a water separator, add 0.6g of p-toluenesulfonic acid, 58.0g of glycerol, 61.0g of benzaldehyde, and 100ml of benzene, heat and stir, and condense to reflux. The reaction temperature was controlled at 130° C., and the reaction time was 2 hours. The reaction solution was washed with water, dried with anhydrous potassium carbonate, distilled under reduced pressure (recovering benzene), and then crystallized in a mixed solution of benzene and petroleum ether (1:1) at -10°C to obtain 18.0 g of glycerin benzaldehyde acetal ether. The rate was 17.8%. The recovered benzene and acetal crystallization mother liquor are reserved for later use.

Step (2): Add 250ml of N,N-dimethylformamide, 3.5mmolNaNO ₂ , 3.5mmolFeCl ₃ 5H ₂ O, 1.4mmolTEMPO (2 , 2,6,6-tetramethylpiperidine-1-oxyl radical), and then added 17.8g of glycerol benzaldehyde acetal. Under the conditions of room temperature and magnetic stirring, a sufficient amount of purified air is introduced as the oxidant, the rotameter is adjusted to 2000ml/min, and the bubbling reaction is carried out, and the reaction is completed after 6-8 hours. After the reaction solution was washed with water and dried over anhydrous magnesium sulfate, N,N-dimethylformamide was recovered by distillation under reduced pressure. After distillation, the solid was recrystallized with diethyl ether and dried under vacuum at room temperature to obtain 12.5 g of 5-carbonyl-2-phenyl-1,3-dioxane with a yield of 70%.

Step (3): Wash the CD550 strong-acid cation exchange resin with deionized water, soak it in deionized water for 24 hours, take it out and dry it for later use. Add 12.5g of 5-carbonyl-2-phenyl-1,3-dioxane and 100ml of deionized water into a three-necked flask equipped with a condenser, heat and stir to 80°C, and then add 35.0g of CD550 strong acid cation exchange resin, using thin layer chromatography to track and detect the reaction end point. After the reaction was completed, the catalyst was removed by suction filtration under reduced pressure, the filtrate was washed with n-hexane, then n-butanol was added, and water was removed by vacuum azeotropic distillation at 40°C. Stir the crystals at room temperature, filter and wash the crystals with acetone at 0°C, and dry at a temperature lower than 40°C to obtain 6.2 g of 1,3-dihydroxyacetone dimer with a yield of 98.5%. The chemical structure of the product was confirmed by HNMR analysis, and the color development of the phosphomolybdic acid solution was a positive reaction.

Embodiment five

Step (1): In a 250ml round bottom flask equipped with a condenser and a water separator, add 0.6g of p-toluenesulfonic acid, 58.0g of glycerol, 61.0g of benzaldehyde, and 100ml of benzene, heat and stir, and condense to reflux. The reaction temperature was controlled at 130° C., and the reaction time was 2 hours. The reaction solution was washed with water, dried, and distilled under reduced pressure (recovering benzene), and then crystallized in a mixed solution of benzene and petroleum ether (1:1) at -10°C to obtain 20.0 g of glycerol benzaldehyde acetal ether, with a yield of 19.8%. .

Step (2): Add 250ml N,N-dimethylformamide, 3.6mmolNaNO ₂ , 3.6mmolFeCl ₃ 5H ₂ O, 1.5mmolTEMPO(2,2 , 6,6-tetramethylpiperidine-1-oxyl radical), and then added 19.8g of glycerol benzaldehyde acetal. Under the condition of room temperature and magnetic stirring, pure oxygen is used as the oxidant, the rotameter is adjusted to 500ml/min, and the bubbling reaction is carried out, and the reaction ends after 6-8 hours. After the reaction solution was washed with water and dried over anhydrous magnesium sulfate, N,N-dimethylformamide was recovered by distillation under reduced pressure. After distillation, the solid was recrystallized with diethyl ether and dried under vacuum at room temperature to obtain 14.8 g of 5-carbonyl-2-phenyl-1,3-dioxane with a yield of 75%.

Step (3): Wash the CD550 strong-acid cation exchange resin with deionized water, soak it in deionized water for 24 hours, take it out and dry it for later use. Add 14.8g of 5-carbonyl-2-phenyl-1,3-dioxane and 100ml of deionized water into a three-necked flask equipped with a condenser, heat and stir to 60°C, and then add 40.0g of CD550 strong acid cation exchange resin, using thin layer chromatography to track and detect the reaction end point. After the reaction was completed, the catalyst was removed by suction filtration under reduced pressure, the filtrate was washed with n-hexane, then n-butanol was added, and water was removed by vacuum azeotropic distillation at 40°C. Stir the crystals at room temperature, filter and wash the crystals with acetone at 0°C, and dry at a temperature lower than 40°C to obtain 7.3 g of 1,3-dihydroxyacetone dimer with a yield of 98.0%. The chemical structure of the product was confirmed by HNMR analysis, and the color development of the phosphomolybdic acid solution was a positive reaction.

Claims (7)

1. the preparation method of a 3-otan; It is characterized in that said preparation method is: (1) acetalation: in the presence of the band aqua, acetalation takes place and obtains structure suc as formula the glycerine phenyl aldehyde acetal ether shown in (I) in glycerine and phenyl aldehyde under acid catalyst A effect; Described acid catalyst A is sulfuric acid, p-methyl benzenesulfonic acid or strongly acidic cation-exchange; Described band aqua is benzene or toluene; (2) oxidizing reaction: described glycerine phenyl aldehyde acetal ether in organic solvent under the oxygenant effect the oxidized structure that obtains suc as formula the 5-carbonyl-2-phenyl-1 shown in (II), 3-dioxane; Described oxygenant is the air or oxygen of capacity, and also add catalyzer 2,2,6,6-tetramethyl piperidine-1-oxyradical, NaNO in the reaction system this moment ₂And FeCl ₃Perhaps described oxygenant is chromium trioxide two pyridines, chromium trioxide pyridine hydrochloride or hydrochloric acid dimethylammonium chromium trioxide; (3) hydrolysis reaction: said 5-carbonyl-2-phenyl-1, the hydrolysis in the presence of acid catalyst B of 3-dioxane makes structure suc as formula 1 shown in (III), 3-otan dimer; Described acid catalyst B is a solid acid catalyst, and said solid acid catalyst is selected from the CD550 strongly acidic cation-exchange, D072 strongly acidic cation-exchange or D061 strongly acidic cation-exchange;

2. as claimed in claim 11; The preparation method of 3-otan; It is characterized in that said step (1) acetalation specifically carries out according to following steps: glycerine, phenyl aldehyde, acid catalyst A and band aqua are joined in the reaction vessel; Be warming up to 100～130 ℃ of reactions 1～6 hour under stirring, after reaction finished, aldolization liquid obtained structure suc as formula the glycerine phenyl aldehyde acetal ether shown in (I) through separation and purification; The amount of substance ratio that feeds intake of said glycerine, phenyl aldehyde is 1:1.0～1.5, and the consumption of said acid catalyst A is 1～10% of a glycerine weight.

3. as claimed in claim 11; The preparation method of 3-otan; It is characterized in that said step (2) oxidizing reaction specifically carries out according to following steps: glycerine phenyl aldehyde acetal ether is joined in the organic solvent that contains oxygenant, under room temperature, reacted 0.5～10 hour, after reaction finishes; Oxidation afterreaction liquid obtains structure suc as formula the 5-carbonyl-2-phenyl-1 shown in (II), 3-dioxane through separation and purification.

4. as claimed in claim 11, the preparation method of 3-otan is characterized in that said step (3) hydrolysis reaction specifically carries out according to following steps: with 5-carbonyl-2-phenyl-1; 3-dioxane, acid catalyst B and deionized water join in the reaction vessel respectively; Be warming up to 50～90 ℃ under stirring, reacted 2～10 hours, after reaction is accomplished; Obtain 1 through separation and purification, 3-otan dimer; The consumption of said acid catalyst B is 5-carbonyl-2-phenyl-1,1～4 times of 3-dioxane weight.

5. described 1 like one of claim 1～4, the preparation method of 3-otan, the oxygenant that it is characterized in that using in said step (2) oxidizing reaction is the air or oxygen of capacity; Also add catalyzer 2 in the reaction system this moment; 2,6,6-tetramethyl piperidine-1-oxyradical, NaNO ₂And FeCl ₃, added 2,2,6,6-tetramethyl piperidine-1-oxyradical, NaNO ₂And FeCl ₃Mole dosage be respectively 0.1～10%, 0.3～10% and 0.3～10% of glycerine phenyl aldehyde acetal ether molar weight.

6. described 1 like one of claim 1～4, the preparation method of 3-otan is characterized in that the oxygenant that uses in said step (2) oxidizing reaction is chromium trioxide two pyridines, chromium trioxide pyridine hydrochloride or hydrochloric acid dimethylammonium chromium trioxide; The consumption of said oxygenant is 2～5 times of glycerine phenyl aldehyde acetal ether (I) weight.

7. described 1 like one of claim 1～4, the preparation method of 3-otan is characterized in that the organic solvent that uses in said step (2) oxidizing reaction is methylene dichloride, trichloromethane, hexanaphthene or N, dinethylformamide.

Images