Patent Application
20180057429
The disclosure relates to a system and a method for preparing an aromatic derivative.
The direct oxidation of a benzyl group of aromatic hydrocarbons is an important chemical reaction to provide the corresponding aromatic derivatives. However, the metal reagent and by-product produced by the above reaction are usually not reusable, resulting in a large amount of contamination and waste, and also incurring a high production cost. For oxidation, the above reaction typically uses halogen elements, especially chlorine, which is relatively cheaper. However, when chlorine is reacted into chloride, electrolysis is required to regenerate the chlorine, thus making recycling difficult. Moreover, in the prior art, an independent two-stage process is required to prepare an aromatic derivative, which leads to complicated steps of the process and decreased production efficiency.
To address the above issues, the disclosure provides a system and a method for preparing aromatic derivatives that can simplify the steps of the process and increase the yield. Furthermore, the waste generated by the reaction can be recycled and reused, thereby reducing the production cost and improving production efficiency.
According to an embodiment, the disclosure provides a system for preparing an aromatic derivative, comprising: a photo-bromination reaction section for performing a photocatalytic reaction of an aromatic hydrocarbon and a brominating agent to form an aromatic hydrocarbon bromide; a substitution reaction section for performing a substitution reaction of the aromatic hydrocarbon bromide from the photo-bromination reaction section with an alkali base compound or an alkali carboxylate compound to form an aromatic derivative; and a regeneration unit for reacting an alkali metal bromide formed by the substitution reaction section with an acid to form a hydrobromic acid. The regeneration unit is in fluid communication with the photo-bromination reaction section, such that the hydrobromic acid is recycled to the photo-bromination reaction section.
According to another embodiment, the disclosure provides a system for preparing an aromatic derivative, comprising: a reaction tank for containing a reaction solution, wherein the reaction solution comprises an aromatic hydrocarbon and a brominating agent; a lighting device for performing a photo-bromination reaction of the aromatic hydrocarbon and the brominating agent from the reaction tank to form a brominated product stream, wherein the brominated product stream comprises a liquid unreacted aromatic hydrocarbon and a solid aromatic hydrocarbon bromide. The system further comprises: a separation unit for separating the solid aromatic hydrocarbon bromide from the liquid unreacted aromatic hydrocarbon, wherein the separation unit is in fluid communication with the reaction tank, such that the liquid unreacted aromatic hydrocarbon is recycled to the reaction tank; and a substitution reactor for performing a substitution reaction of the solid aromatic hydrocarbon bromide from the separation unit with an alkali base compound or an alkali carboxylate compound to form an aromatic derivative.
According to yet another embodiment, the disclosure provides a method for preparing an aromatic derivative, comprising: (a) performing a photo-bromination reaction of an aromatic hydrocarbon and a brominating agent in a first solvent to form an aromatic hydrocarbon bromide; (b) performing a substitution reaction of the aromatic hydrocarbon bromide with an alkali base compound or an alkali carboxylate compound in a second solvent to form an aromatic derivative; and (c) reacting an alkali metal bromide formed by the substitution reaction with an acid to form a hydrobromic acid, and recycling the hydrobromic acid for step (a).
A detailed description is given in the following embodiments with reference to the accompanying drawings.
The disclosure can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:
Even if a plurality of technical features is simultaneously disclosed by any embodiments described below, it is not meant that a person using the disclosure has to simultaneously implement all the technical features of any embodiments. That is, as long as the possibility of implementation is not affected, a person with ordinary skill in the art is able to selectively implement a portion of technical feature(s) rather than all of the technical features as desired or design requirements in accordance with the disclosure of the disclosure, thereby increasing the flexibility of the disclosure.
The disclosure provides a system and a method for preparing an aromatic derivative which can efficiently recycle by-products. Since the by-product generated by the reaction can be recycled and reused, it is possible to reduce the energy consumption, reduce the production cost and improve production efficiency. Furthermore, in some embodiments, since an aromatic derivative can be formed from an aromatic hydrocarbon without purifying the intermediate through a purification unit such as a recrystallization unit or a distillation unit, the steps of the process can be simplified.
The term “molar equivalent” as used herein refers to the moles of one compound divided by the moles of another compound which is actually reacted. For example, 1 molar equivalent of p-xylene corresponds to 2.5 molar equivalents of hydrogen peroxide in an aqueous solution of hydrogen peroxide.
Referring to
For example, as shown in Formula (1), the photo-bromination reaction section A may be used to perform a photocatalytic reaction of p-xylene and the brominating agent (e.g., a combination of hydrobromic acid (HBr) and aqueous solution of hydrogen peroxide (H2O2)) to form α, α′-dibromo-p-xylene. Furthermore, the substitution reaction section C may be used to perform a substitution reaction of α, α′-dibromo-p-xylene from the photo-bromination reaction section A with sodium formate (HCOONa) to form p-xylylene glycol. Moreover, a regeneration unit G may be used to react sodium bromide (NaBr) formed by the substitution reaction section C with sulfuric acid to form hydrobromic acid (HBr), and hydrobromic acid (HBr) is recycled to the photo-bromination reaction section A. It should be noted that the compounds used in Formula (1) are merely examples and are not intended to be limiting.
Specifically, the preparation system 100 and the steps of the process of preparing the aromatic derivative will be described in more detail below. As shown in
First, as shown in
The aromatic hydrocarbon 10 used in the disclosure is not particularly limited. The aromatic hydrocarbon 10 may be, for example, a mono-aromatic cyclic hydrocarbon, a bi-aromatic cyclic hydrocarbon or a tri-aromatic hydrocarbon. In some embodiments, the mono-aromatic cyclic hydrocarbon may be
wherein R is a linear or branched alkyl group having 1 to 15 carbon atoms;
wherein each of R and R1 is independently a linear or branched alkyl group having 1 to 15 carbon atoms, R1 may be on any position of the aromatic ring, and the total number of R and R1 substituent is 6 or less; or a combination thereof. In some embodiments, the bi-aromatic cyclic hydrocarbon may be
wherein R is a linear or branched alkyl group having 1 to 15 carbon atoms;
wherein each of R and R1 is independently a linear or branched alkyl group having 1 to 15 carbon atoms, R and R1 may be on any position of the aromatic ring, and the total number of R and R1 substituent is 10 or less;
wherein each of R and R1 is independently a linear or branched alkyl group having 1 to 15 carbon atoms, R and R1 may be on any position of the aromatic ring, and the total number of R and R1 substituent is 8 or less;
wherein each of R and R1 is independently a linear or branched alkyl group having 1 to 15 carbon atoms, R and R1 may be on any position of the aromatic ring, and the total number of R and R1 substituent is 10 or less; wherein each of X1 and X2 is independently hydrogen or a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms;
wherein each of R and R1 is independently a linear or branched alkyl group having 1 to 15 carbon atoms, R and R1 may be on any position of the aromatic ring, and the total number of R and R1 substituent is 10 or less;
wherein each of R and R1 is independently a linear or branched alkyl group having 1 to 15 carbon atoms, R and R1 may be on any position of the aromatic ring, and the total number of R and R1 substituent is 10 or less; or a combination thereof. In some embodiments, the tri-aromatic cyclic hydrocarbon may be
wherein R is a linear or branched alkyl group having 1 to 15 carbon atoms;
wherein Ph1 may be
and Ph1 and Ph2 may be on any position of the aromatic ring; wherein each of R, R1 and R2 is independently a linear or branched alkyl group having 1 to 15 carbon atoms, R, R1 and R2 may be on any position of the aromatic ring, and the total number of R, R1 and R2 substituent is 14 or less;
wherein each of R, R1 and R2 is independently a linear or branched alkyl group having 1 to 15 carbon atoms, R, R1 and R2 may be on any position of the aromatic ring, and the total number of R, R1 and R2 substituent is 10 or less;
wherein each of R, R1 and R2 is independently a linear or branched alkyl group having 1 to 15 carbon atoms, R, R1 and R2 may be on any position of the aromatic ring, and the total number of R, R1 and R2 substituent is 14 or less; wherein each of X1, X2, X3 and X4 is independently hydrogen or a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms;
wherein each of R, R1 and R2 is independently a linear or branched alkyl group having 1 to 15 carbon atoms, R, R1 and R2 may be on any position of the aromatic ring, and the total number of R, R1 and R2 substituent is 14 or less;
wherein each of R, R1 and R2 is independently a linear or branched alkyl group having 1 to 15 carbon atoms, R, R1 and R2 may be on any position of the aromatic ring, and the total number of R, R1 and R2 substituent is 14 or less; or a combination thereof.
The solvent 12 suitable for the disclosure may be a halogenated hydrocarbon, such as dichloroethane, cyclohexane or other halogenated hydrocarbons which can dissolve the aromatic hydrocarbon.
The brominated agent 11 suitable for the disclosure may be bromine water (Br2). It should be noted that although bromine water (Br2) is readily available, it is highly hazardous in handling, delivering and using. Thus, the brominating agent 11 is preferably a mixture having hydrobromic acid (HBr) and aqueous solution of hydrogen peroxide (H2O2); a mixture having sodium bromide (NaBr), sulfuric acid (H2SO4) and aqueous solution of hydrogen peroxide (H2O2); or other mixture capable of producing bromine water (Br2).
The order of adding the composition of the brominating agent 11 may be adjusted in accordance with the design requirement. For example, after cooling the mixture, the hydrobromic acid 11a is added to the photo-bromination reaction section A. Then, the aqueous solution of hydrogen peroxide 11b is titrated to the above mixture at a temperature of about −10° C. to 30° C. (preferably about 0° C. to 10° C.). In other embodiments, the aqueous solution of hydrogen peroxide 11b may be added before adding the hydrobromic acid 11a. In some embodiments, the molar equivalent ratio of the aromatic hydrocarbon 10, the hydrobromic acid 11a and the solvent 12 is 1:2-3:1-20. In some embodiments, the molar equivalent ratio of the aqueous solution of hydrogen peroxide 11b to the aromatic hydrocarbon 10 is 2-5:1.
Then, the mixture is irradiated with a light source to perform a photocatalytic reaction, thereby forming the aromatic hydrocarbon bromide 16.
In some embodiments, a wavelength of the light source is in a range from about 400 nm to 700 nm, preferably about 420 nm. The power of the light source is in a range from about 20 watt to 200 watt, preferably in a range from about 40 watt to 100 watt, more preferably about 80 watt. In some embodiments, the reaction time of the photo-bromination reaction is in a range from about 0.5 to 24 hours, preferably in a range from about 4 to 12 hours.
It should be noted that since addition of the aqueous solution of hydrogen peroxide 11b to the photo-bromination reaction section A is an exothermic reaction, overheating may produce an unnecessary product. Thus, in the titration process, the temperature of the photo-bromination reaction section A is preferably maintained at about 15° C. or less. If the temperature exceeds 15° C., the addition of the aqueous solution of hydrogen peroxide 11b is stopped until the temperature is lowered.
Referring to
In some embodiments, the alkali base compound 14a may be sodium hydroxide (NaOH), sodium carbonate (Na2CO3), potassium hydroxide (KOH) or a combination thereof. In some embodiments, the alkali carboxylate compound 14b may be sodium formate, sodium acetate or a combination thereof. In some embodiments, the molar equivalent ratio of the alkali base compound 14a or the alkali carboxylate compound 14b to the aromatic hydrocarbon bromide 16 is 2-5:1, preferably 2.5:1.
In some embodiments, a surfactant may be selectively added to the substitution reaction section C to improve the compatibility of the organics and water. In these embodiments, the surfactant may be acetone, 1,4-dioxane or a combination thereof, and the weight ratio of the surfactant to water 13 may be 0.5-4:1.
It should be noted that in this embodiment, the crude product from the photo-bromination reaction section A is directly received by the substitution reaction section C without passing through a purification unit such as a recrystallization unit or a distillation unit. That is, none of steps for purifying (e.g., recrystallizing or distilling) the intermediate is performed during the process of forming the crude product of the aromatic alcohol or the aromatic ester. Accordingly, the aromatic alcohol or the aromatic ester is prepared by an one-pot process, and thus the preparation steps can be simplified.
Still referring to
As shown in
Also, the resulting aromatic derivative product, such as the aromatic alcohol 26a or the aromatic ester 26b, is determined by the reactant (such as the alkali base compound 14a or the alkali carboxylate compound 14b) of the substitution reaction. As exemplified by the following Formula (2a), in the case where a reactant of a substitution reaction is an alkali base compound (e.g., sodium hydroxide), a resulting product is an aromatic alcohol. Furthermore, as exemplified by the following Formula (2b), in the case where a reactant of a substitution reaction is an alkali carboxylate compound (e.g., sodium acetate), the resulting product is an aromatic ester. In certain embodiments, in the case where a reactant of a substitution reaction is sodium formate, the resulting product is an aromatic alcohol. For example, as shown in the above-mentioned Formula (1), in the case where a reactant of a substitution reaction is sodium formate, p-xylene eventually forms p-xylylene glycol. It should be noted that the compounds used in Formula (1), Formula (2a) and Formula (2b) are merely examples and are not intended to be limiting.
Still referring to
The regeneration unit G is used to react the alkali metal bromide 27 from the distillation unit F to regenerate the hydrobromic acid 11a. Specifically, the concentrated sulfuric acid 30 is added to the regeneration unit G and reacted with the alkali metal bromide 27 to form the hydrobromic acid 11a and an alkali metal salt 32. Furthermore, the regeneration unit G is in fluid communication with the photo-bromination reaction section A, such that the hydrobromic acid 11a obtained by the regeneration unit G is recycled to the photo-bromination reaction section A. In some embodiments, the molar equivalent ratio of the alkali metal bromide 27 to the concentrated sulfuric acid 30 is 1: 2-4. In some embodiments, an additional purification step (e.g., a recrystallization step) of the alkali metal bromide 27 is performed before the alkali metal bromide 27 is moved to the regeneration unit G. It is noted that the reaction of processing the alkali metal bromide 27 to regenerate the hydrobromic acid 11a can be accomplished by simple operations such as heating and distilling under reduced pressure. In contrast, a chlorinating agent (e.g., chlorine gas) used in the prior art requires electrolyzing the chloride produced by the reaction to regenerate and recycle the chlorinating agent. Furthermore, the chlor-alkali industrial process makes enormous demands on the purity of sodium chloride, and thus recycling sodium chloride is relatively costly. Therefore, the system provided by the disclosure can recycle the hydrobromic acid without using the aforementioned electrolysis technology, thereby saving the preparation cost and improving production efficiency.
Furthermore, a neutralization unit H (e.g., a commercially available acid-base neutralization tank) is used to perform a neutralization reaction of the acidic compound 28 and water 29 from the distillation unit F. Specifically, the basic compound 34 is added to the neutralizing unit H, and the neutralization reaction of the acidic compound 28 and water 29 is performed with the basic compound 34 to form the basic alkali metal compound 14a or the alkali metal carboxylate 14b. Furthermore, the neutralization unit H is in fluid communication with the substitution reaction section C, such that the alkali base compound 14a or the alkali carboxylate compound 14b is recycled to the substitution reaction section C.
It will be understood that in this embodiment, a by-product produced by the photo-bromination reaction section A and the substitution reaction section C can be regenerated as a reactant and recycled to the reactor after being processed. Therefore, it is possible to reduce the energy consumption, reduce the production cost and improve production efficiency.
Referring to
In detail, after the photocatalytic reaction is performed in the photo-bromination reaction section A of a reactor R1 to form the aromatic hydrocarbon bromide 16, the aromatic hydrocarbon bromide 16 is taken out from the reactor R1 and moved to another reaction R2. Next, the substitution reaction is performed in the substitution reaction section C of the reactor R2 to form a reaction mixture 18. The reaction mixture 18 includes the crude product of the aromatic alcohol 26a or the aromatic ester 26b.
In another embodiment, the preparation system 200 may further include a separation unit B for separating the aromatic hydrocarbon bromide 16 formed by the reactor R1 and then moving the aromatic hydrocarbon bromide 16 to the reactor R2, thereby improving production efficiency.
In the embodiments using the system 200, the yield of the aromatic alcohol 26a or the aromatic ester 26b may be up to 75% or more, and in certain examples, the yield may be up to 75%-96%. The purity of the aromatic alcohol 26a or the aromatic ester 26b may be up to 90% or more, and in certain examples, the purity may be up to 90%-95%.
It should be noted that although the photo-bromination reaction section A and the substitution reaction section C of the preparation system 200 are located in separate reactors, the crude product from the photo-bromination reaction section A is directly received by the substitution reaction section C without passing through a purification unit such as a recrystallization unit or a distillation unit. That is, none of steps for purifying (e.g., recrystallizing or distilling) the intermediate is performed during the process of forming the crude product of the aromatic alcohol or the aromatic ester. Accordingly, the preparation steps can be simplified.
Furthermore, in the preparation system 100 shown in
Referring to
As shown in
In this embodiment, the aromatic hydrocarbon 10, the brominating agent 11, the solvent 12 and the reaction condition may be the same as those of the first embodiment, which are not described again here in detail.
Still referring to
In this embodiment, the separation unit K may be a centrifugal device having a filter plate for performing a separation step. Specifically, the reaction mixture 55 obtained from the reaction tank I is moved to the separation unit K. The reaction mixture 55 is then separated into the liquid unreacted aromatic hydrocarbon 10 and the solid aromatic bromide 58, and the solid aromatic bromide 58 is retained in the separation unit K and then moved to the substitution reactor L (to be described later). In other embodiments, the separation unit K may be located in the reaction tank I, allowing the reaction mixture 55 to be separated directly by the separation unit K in the reaction tank I.
Also, the lighting device J has a cooling system and a light source for performing a photo-bromination reaction. In detail, the lighting device J is in fluid communication with the separation unit K, such that the photo-bromination reaction of the liquid unreacted aromatic hydrocarbon 10 from the separation unit K is further performed to form a brominated product stream. The brominated product stream includes the liquid unreacted aromatic hydrocarbon and the solid aromatic bromide.
More specifically, the liquid unreacted aromatic hydrocarbon 10 from the separation unit K is moved to the light device J, and the liquid unreacted aromatic hydrocarbon 10 is irradiated with the light source at a temperature of about −10° C. to 30° C. (preferably about 0° C. to 10° C.) to perform the photo-bromination reaction, thereby forming the brominated product stream (i.e., a brominated mixture 56). The brominated mixture 56 includes the liquid unreacted aromatic hydrocarbon 10 and the solid aromatic bromide 58. In some embodiments, a wavelength of the light source is in a range from about 400 nm to 700 nm, preferably about 420 nm. The power of the light source is in a range from about 20 watt to 200 watt, preferably in a range from about 40 watt to 100 watt, more preferably about 80 watt. In some embodiments, the reaction time of the photo-bromination reaction is in a range from about 0.5 to 24 hours, preferably in a range from about 4 to 12 hours.
Furthermore, the lighting device J is in fluid communication with the reaction tank I, such that the brominated mixture 56 is recycled to the reaction tank I. The liquid unreacted aromatic hydrocarbon 10 and the solid aromatic bromide 58 are moved to the separation unit K once again through the cycle process.
In other embodiments, another separation unit may be additionally provided between the lighting device J and the reaction tank I, and said another separation unit may be in fluid communication with the substitution reactor L. Accordingly, the brominated mixture 56 from the lighting device J is separated, and the liquid unreacted aromatic hydrocarbon 10 is recycled to the reaction tank I while the solid aromatic bromide 58 is retained in said another separation unit and subsequently moved to the substitution reactor L.
Still referring to
The lighting device J has a cooling system and a light source for performing a photo-bromination reaction of the aromatic hydrocarbon 10 and the brominating agent 11 of the reaction mixture 55 from the reaction tank I, thereby forming a brominated product stream. The brominated product stream includes the liquid unreacted aromatic hydrocarbon and the solid aromatic bromide. Specifically, the reaction mixture 55 of the reaction tank I is moved to the light device J, and the reaction mixture 55 is irradiated with the light source at a temperature of about −10° C. to 30° C. (preferably about 0° C. to 10° C.) to perform the photo-bromination reaction, thereby forming the brominated product stream (i.e., a brominated mixture 56). The brominated mixture 56 includes the liquid unreacted aromatic hydrocarbon 10 and the solid aromatic bromide 58. In this embodiment, the condition of the photo-bromination reaction may be the same as that of the above embodiment, which is not described again here in detail.
Furthermore, the separation unit K may be a centrifugal device having a filter plate for performing a separation step. Specifically, the brominated mixture 56 obtained from the lighting device J is moved to the separation unit K, and the brominated mixture 56 is then separated into the liquid unreacted aromatic hydrocarbon 10 and the solid aromatic bromide 58. The separation unit K is in fluid communication with the reaction tank I, such that the liquid unreacted aromatic hydrocarbon 10 is recycled to the reaction tank I, while the solid aromatic bromide 58 is retained in the separation unit K and subsequently moved to the substitution reactor L (to be described later).
Since the reaction tank I, the lighting device J and the separation unit K form an external circulation system, the liquid unreacted aromatic hydrocarbon 10 can be repeatedly moved to the lighting device 56 for the photo-bromination reaction until the solid aromatic hydrocarbon bromide 58 is formed. Accordingly, all of the aromatic hydrocarbon reactants can be reacted sufficiently. Furthermore, since most of the solid aromatic bromide 58 is retained in the separation unit K without moving into to the lighting device J through the external circulation system, adverse effects which may reduce the efficiency of the photo-bromination reaction can be prevented. Moreover, the aromatic hydrocarbon 10 and the brominating agent 11 can be continuously added to the reaction tank I, such that the photo-bromination reaction may form a continuous reaction in the external circulation system. Accordingly, the product can be mass produced and the process efficiency can be improved.
Also, in the embodiment in which the separation unit is provided before the lighting device, all the mixture is passed through the separation unit K before moving into the lighting device J. Thus, it is ensured that all the solid substances (e.g., solid aromatic bromide 58) are retained in the separation unit without moving into the lighting device J, thereby preventing adverse effects which may reduce the efficiency of the photo-bromination reaction.
Still referring to
In this embodiment, the alkali base compound 14a, the alkali carboxylate compound 14b, the aromatic hydrocarbon bromide 58 and the reaction condition may be the same as those of the first embodiment, which are not described again here in detail.
The crude product from the separation unit K is directly received by the substitution reaction section L without passing through a purification unit such as a recrystallization unit or a distillation unit. That is, none of steps for purifying (e.g., recrystallizing or distilling) the intermediate is performed during the process of forming the crude product of the aromatic alcohol or the aromatic ester. Accordingly, the preparation steps can be simplified.
As shown in
Furthermore, a neutralization unit N (e.g., a commercially available acid-base neutralization tank) is used to perform a neutralization reaction of the acidic compound 28 and water 29 from the distillation unit M. Specifically, the basic compound 34 is added to the neutralizing unit N, and the neutralization reaction of the acidic compound 28 and water 29 is performed with the basic compound 34 to form the basic alkali metal compound 14a or the alkali metal carboxylate 14b. Furthermore, the neutralization unit N is in fluid communication with the substitution reaction section L, such that the alkali base compound 14a or the alkali carboxylate compound 14b is recycled to the substitution reaction section L.
Still referring to
As shown in
As shown in
In this embodiment, since the photo-bromination reaction can be performed continuously, all of the aromatic hydrocarbon reactants can be reacted sufficiently. Therefore, production efficiency can be improved and the yield of the aromatic derivative can be increased.
In summary, the disclosure provides a system and a method for preparing an aromatic derivative. Since the by-product generated by the reaction can be recycled and reused, it is possible to reduce the energy consumption, reduce the production cost and improve production efficiency. Furthermore, in certain embodiments, since an aromatic derivative can be formed from an aromatic hydrocarbon without purifying the intermediate through a purification unit such as a recrystallization unit or a distillation unit, the steps of the process can be simplified.
Examples of the aromatic derivatives obtained by the preparation system and the preparation method of the disclosure are provided below. Specifically, the preparation conditions, the reactant formulation, the resulting yield and purity of the aromatic derivatives described in Examples 1-11 are summarized in Table 1 below. The aromatic derivatives of Examples 1 to 5 are prepared by using the preparation system 100 of the first embodiment. The aromatic derivatives of Examples 6 to 8 are prepared by using the preparation system 200 of the above second embodiment. The aromatic derivatives of Examples 9 to 14 are prepared by using the preparation system 300 of the above third embodiment.
In the following Examples, the yield is defined as: the mole number of the aromatic derivative product/the mole number of the aromatic hydrocarbon reactant X 100%.
In the following Examples, the purity of the product is measured by the GC-FID system (Agilent 7890A Single FID SVOA GC System, available form Pace Analytical Services, LLC) as follows:
0.5 g samples were dissolved with 10 g THF, and the samples were sonicated for 0.5 hr. The samples were then filtered and the filtrate was decanted for GC-FID analysis.
GC conditions: J&W DB-1 (60 m×250 um×0.25 um) capillary column; column temperature hold at 80° C. for 2 min, then rising from 80° C. to 260° C. at 10° C./min, and then hold at 260° C. for 5 min.; injection temperature: 300° C.; injection volume: 0.2 μL; mode of sample injection: split flow, split ratio, 100:1; flow rate of carrier gas: 1.50 mL/min; FID temperature: 300° C.
1 molar equivalent of p-xylene (available from ACROS OEGANICS, Sigma-Aldrich), 2.05 molar equivalents of hydrobromic acid (HBr) (48 wt %) and 2.15 molar equivalents of dichloroethane were added in a glass reactor and stirred with a mechanical stirrer at 1 atm and room temperature.
After the temperature of the mixture was cooled to about 5° C. to 10° C. by an ice-water bath, 2.5 molar equivalents of hydrogen peroxide (35 wt %) was slowly added by using a peristaltic pump. Meanwhile, the mixture was irradiated with a light bulb having a wavelength of 400 to 700 nm and a power of 80 W to perform a photocatalytic reaction. In the process of adding hydrogen peroxide aqueous solution, the system temperature was maintained not exceeding 15° C. If the temperature exceeded 15° C., addition of aqueous solution of hydrogen peroxide was stopped until the temperature was lowered. When addition of aqueous solution of hydrogen peroxide was completed, the reaction was terminated when the color of the mixture solution turned from dark yellow to light yellow. The reaction time was about 6 hours and the reaction system was then raised to room temperature.
2.1 molar equivalents of sodium formate (available from LCY Chemical Corp.) and water in the amount of 10 times of sodium formate by weight were directly added to the above glass reactor, and a substitution reaction was performed by refluxing at about 100° C. and 1 atm. The dichloroethane was removed and recycled by an oil-water separation device disposed in the glass reactor while water was retained in the reaction system.
The temperature of the system was lowered to room temperature after the substitution reaction was performed for 6 hours. The reaction mixture was moved to an extraction tank, and an extraction solvent of methyl isobutyl ketone (MIBK) was added to the extraction tank. The weight ratio of the reaction mixture to methyl isobutyl ketone (MIBK) was 1:1. Then, the organic phase of the extract was taken out and the solvent was recycled by a rotary concentrator. Accordingly, p-xylylene glycol was obtained. The yield of p-xylylene glycol was 62% and the purity was 85% measured by GC-FID.
The aqueous phase of the extract was distilled under reduced pressure, and formic acid and water were distilled off. The acid value of formic acid was detected, and a corresponding amount of sodium hydroxide (NaOH) was added to perform a neutralization reaction. Accordingly, sodium formate was obtained and recycled subsequently.
The solid left by the reduced-pressure distillation step was sodium bromide, and sodium bromide was purified by recrystallization and dried. 1 molar equivalent of sodium bromide was mixed with 15 molar equivalents of water in a glass bottle, and the aqueous sodium bromide solution was heated to about 80° C. Then, 97% of concentrated sulfuric acid was added dropwise to the aqueous sodium bromide solution, and the dropping time was controlled for about 30 minutes. After the addition of sulfuric acid was completed, water was concentrated together with the generated hydrobromic acid (HBr) at 125° C. and 1 atm through a vacuum concentration apparatus (the azeotropic temperature of water and hydrobromic acid at 1 atm is 125° C.). The distillate was collected and the regenerated aqueous hydrobromic acid solution was obtained.
The reaction steps and the reaction conditions of Example 2 were substantially the same as those of Example 1 except that in the substitution reaction of Example 2, the reactant formulation was replaced with 2.2 molar equivalents of sodium acetate and water in the amount of 10 times of sodium acetate by weight. The resulting product was 1,4-benzenedimethanol diacetate, and the yield and purity of 1,4-benzenedimethanol diacetate was 62% and 95%, respectively. The detailed reaction formulation and reaction conditions are listed in Table 1.
The reaction steps and the reaction conditions of Example 3 were substantially the same as those of Example 1 except that in the substitution reaction of Example 3, the reactant formulation was replaced with 3 molar equivalents of sodium hydroxide, water and 1,4-dioxane (in which the weight ratio of 1,4-dioxane to water was 1:1, and the total weight of 1,4-dioxane and water was 10 times of sodium hydroxide), and the reaction time was increased to 12 hours. The resulting product was p-xylylene glycol, and the yield and purity of p-xylylene glycol was 65% and 92%, respectively. The detailed reaction formulation and reaction conditions are listed in Table 1.
The reaction steps and the reaction conditions of Example 4 were substantially the same as those of Example 1 except that in the photo-bromination reaction of Example 4, the reactant formulation was replaced with 5 molar equivalents of toluene and 1 molar equivalent of hydrobromic acid (48 wt %), and the amount of aqueous solution of hydrogen peroxide was changed to be 1.2 molar equivalents.
Furthermore, in the substitution reaction of Example 4, the reactant formulation was replaced with 2 molar equivalents of sodium hydroxide, water and 1,4-dioxane (in which the weight ratio of 1,4-dioxane to water was 1:1, and the total weight of 1,4-dioxane and water was 10 times of sodium hydroxide), and the reaction time was reduced to be 6 hours. The resulting product was benzyl alcohol, and the yield and purity of benzyl alcohol was 83% and 93%, respectively. The detailed reaction formulation and reaction conditions are listed in Table 1.
The reaction steps and the reaction conditions of Example 5 were substantially the same as those of Example 1 except that in the photo-bromination reaction of Example 4, the reactant formulation was replaced with 5 molar equivalents of toluene and 1 molar equivalent of hydrobromic acid (48 wt %), and the amount of aqueous solution of hydrogen peroxide was changed to be 1.2 molar equivalents.
Furthermore, in the substitution reaction of Example 5, the reactant formulation was replaced with 2.2 molar equivalents of sodium methacrylate, 1000 ppm of hydroquinone monomethyl ether (as an inhibitor) and water in the amount of 10 times of sodium methacrylate by weight. The resulting product was benzyl methacrylate, and the yield and purity of benzyl methacrylate was 76% and 90%, respectively. The detailed reaction formulation and reaction conditions are listed in Table 1.
1 molar equivalent of p-xylene (available from ACROS OEGANICS, Sigma-Aldrich), 2.05 molar equivalents of hydrobromic acid (HBr) (48 wt %) and 2.15 molar equivalents of dichloroethane were added in a glass reactor and stirred with a mechanical stirrer at 1 atm and room temperature.
After the temperature of the mixture was cooled to about 5° C. to 10° C. by an ice-water bath, 2.5 molar equivalents of hydrogen peroxide (35 wt %) was slowly added by using a peristaltic pump. Meanwhile, the mixture was irradiated with a light bulb having a wavelength of 400 to 700 nm and a power of 80 W to perform a photocatalytic reaction. In the process of adding hydrogen peroxide aqueous solution, the system temperature was maintained not exceeding 15° C. If the temperature exceeded 15° C., addition of aqueous solution of hydrogen peroxide was stopped until the temperature was lowered. When addition of aqueous solution of hydrogen peroxide was completed, the reaction was terminated when the color of the mixture solution turned from dark yellow to light yellow. The reaction time was about 6 hours and the reaction system was then raised to room temperature. A mixture solution having the white solid was obtained in the glass reactor.
Next, the solid of the mixture solution was separated from the liquid by a Buchner funnel, and a white solid intermediate product (i.e., α,α′-dibromo-p-xylene) was obtained. The white solid intermediate product was weighed and moved to another reactor. Furthermore, 2.1 molar equivalents of sodium formate and water in the amount of 10 times of sodium formate by weight were directly added to the other glass reactor, and a substitution reaction was performed by refluxing at about 100° C. and 1 atm.
The temperature of the system was lowered to room temperature after the substitution reaction was performed for 8 hours. The reaction mixture was moved to an extraction tank, and an extraction solvent of methyl isobutyl ketone (MIBK) was added to the extraction tank. The weight ratio of the reaction mixture to methyl isobutyl ketone (MIBK) was 1:1. Then, the organic phase of the extract was taken out and the solvent was recycled by a rotary concentrator. Accordingly, p-xylylene glycol was obtained. The yield of p-xylylene glycol was 92% and the purity was 90% measured by GC-FID.
The aqueous phase of the extract was distilled under reduced pressure, and formic acid and water were distilled off. The acid value of formic acid was detected, and a corresponding amount of sodium hydroxide (NaOH) was added to perform a neutralization reaction. Accordingly, sodium formate was obtained and recycled subsequently.
The solid left by the reduced-pressure distillation step was sodium bromide, and sodium bromide was purified by recrystallization and dried. 1 molar equivalent of sodium bromide was mixed with 15 molar equivalents of water in a glass bottle, and the aqueous sodium bromide solution was heated to about 80° C. Then, 97% of concentrated sulfuric acid was added dropwise to the aqueous sodium bromide solution, and the dropping time was controlled for about 30 minutes. After the addition of sulfuric acid was completed, completed, water was concentrated together with the generated hydrobromic acid (HBr) at 125° C. and 1 atm through a vacuum concentration apparatus (the azeotropic temperature of water and hydrobromic acid at 1 atm is 125 t). The distillate was collected and the regenerated aqueous hydrobromic acid solution was obtained.
The reaction steps and the reaction conditions of Example 7 were substantially the same as those of Example 6 except that in the substitution reaction of Example 7, the reactant formulation was replaced with 2.2 molar equivalents of sodium acetate and water in the amount of 10 times of sodium acetate by weight. The resulting product was 1,4-benzenedimethanol diacetate, and the yield and purity of 1,4-benzenedimethanol diacetate was 96% and 95%, respectively. The detailed reaction formulation and reaction conditions are listed in Table 1.
The reaction steps and the reaction conditions of Example 8 were substantially the same as those of Example 6 except that in the substitution reaction of Example 8, the reactant formulation was replaced with 3 molar equivalents of sodium hydroxide, water and 1,4-dioxane (in which the weight ratio of 1,4-dioxane to water was 1:1, and the total weight of 1,4-dioxane and water was 10 times of sodium hydroxide), and the reaction time was increased to 12 hours. The resulting product was p-xylylene glycol, and the yield and purity of p-xylylene glycol was 75% and 93%, respectively. The detailed reaction formulation and reaction conditions are listed in Table 1.
1 molar equivalent of p-xylene, 2.05 molar equivalents of hydrobromic acid (HBr) (48 wt %) and 2.15 molar equivalents of dichloroethane were added in a glass reactor having a Teflon filter plate and stirred with a mechanical stirrer at 1 atm and room temperature.
After the temperature of the mixture was lowered to about 5° C. to 10° C. by an ice-water bath, 2.5 molar equivalents of hydrogen peroxide (35 wt %) was slowly added to the glass reactor by using a peristaltic pump.
The reaction solution of the glass reactor was pumped into a lighting reactor having a cooling system by using another peristaltic pump. The reaction solution was irradiated with a light bulb having a wavelength of 400 to 700 nm and a power of 80 W to perform a photocatalytic reaction, thereby forming a mixture solution having a solid. The mixture solution was returned to the original glass reactor to form an external circulation system. The temperature of the entire external circulation system was maintained not exceeding 15° C. If the temperature exceeded 15° C., addition of aqueous solution of hydrogen peroxide was stopped until the temperature was lowered.
The solid was retained in the glass reactor by the Teflon filter plate of the glass reactor, so that the solid did not move into to the lighting reactor through the external circulation system. Accordingly, adverse effects which may reduce the efficiency of the lighting reaction could be prevented. When addition of aqueous solution of hydrogen peroxide was completed, the reaction was terminated depending on the color of the mixture solution from dark yellow to light yellow. The reaction time was about 6 hours.
The solid of the mixture solution was separated from the liquid by a Buchner funnel, and a white solid intermediate product (i.e., α, α′-dibromo-p-xylene) was obtained. The white solid intermediate product was weighed and moved to another reactor. Furthermore, 2.1 molar equivalents of sodium formate and water in the amount of 10 times of sodium formate by weight were directly added to the other glass reactor, and a substitution reaction was performed by refluxing at about 100° C. and 1 atm.
The temperature of the system was lowered to room temperature after the substitution reaction was performed for 8 hours. The reaction mixture was distilled under reduced pressure, and formic acid and water were distilled off. The acid value of formic acid was detected, and a corresponding amount of sodium hydroxide (NaOH) was added to perform a neutralization reaction. Accordingly, sodium formate was obtained and recycled subsequently.
The solid left by the reduced-pressure distillation step was moved to an extraction tank, and an extraction solvent of methyl isobutyl ketone (MIBK) was added to the extraction tank. The weight ratio of the reaction mixture to methyl isobutyl ketone (MIBK) was 1:1. Then, the organic phase of the extract was taken out and the solvent was recycled by a rotary concentrator. Accordingly, p-xylylene glycol was obtained. The yield of p-xylylene glycol was 95% and the purity was 92% measured by GC-FID.
Furthermore, the aqueous phase of the extract was sodium bromide, and sodium bromide was purified by recrystallization and dried. 1 molar equivalent of sodium bromide was mixed with 15 molar equivalents of water in a glass bottle, and the aqueous sodium bromide solution was heated to about 80° C. Then, 97% of concentrated sulfuric acid was added dropwise to the aqueous sodium bromide solution, and the dropping time was controlled for about 30 minutes. After the addition of sulfuric acid was completed, water was concentrated together with the generated hydrobromic acid (HBr) at 125° C. and 1 atm through a vacuum concentration apparatus (the azeotropic temperature of water and hydrobromic acid at 1 atm is 125 t). The distillate was collected and the regenerated aqueous hydrobromic acid solution was obtained.
The reaction steps and the reaction conditions of Example 10 were substantially the same as those of Example 9 except that in the substitution reaction of Example 10, the reactant formulation was replaced with 2.2 molar equivalents of sodium acetate and water in the amount of 10 times of sodium acetate by weight. The resulting product was 1,4-benzenedimethanol diacetate, and the yield and purity of 1,4-benzenedimethanol diacetate was 95% and 95%, respectively. The detailed reaction formulation and reaction conditions are listed in Table 1.
The reaction steps and the reaction conditions of Example 11 were substantially the same as those of Example 9 except that in the substitution reaction of Example 11, the reactant formulation was replaced with 3 molar equivalents of sodium hydroxide, water and 1,4-dioxane (in which the weight ratio of 1,4-dioxane to water was 1:1, and the total weight of 1,4-dioxane and water was 10 times that of sodium hydroxide), and the reaction time was increased to 12 hours. The resulting product was p-xylylene glycol, and the yield and purity of p-xylylene glycol was 78% and 93%, respectively. The detailed reaction foimulation and reaction conditions are listed in Table 1.
The reaction steps and the reactant formulation of Example 12 were substantially the same as those of Example 9 except that the substitution reaction of Example 12 was performed at 3 atm and 130° C. for 3 hours. The resulting product was p-xylylene glycol, and the yield and purity of p-xylylene glycol was 92% and 94%, respectively. The detailed reaction formulation and reaction conditions are listed in Table 1.
The reaction steps of Example 13 were substantially the same as those of Example 9 except that in the substitution reaction of Example 13, the reactant formulation was replaced with 2.1 molar equivalents of sodium formate and water in the amount of 5 times of sodium formate by weight. Furthermore, the substitution reaction of Example 13 was performed at 3 atm and 130° C. for 1 hour. The resulting product was p-xylylene glycol, and the yield and purity of p-xylylene glycol was 93% and 92%, respectively. The detailed reaction formulation and reaction conditions are listed in Table 1.
The reaction steps and the reactant formulation of Example 14 were substantially the same as those of Example 9 except that the substitution reaction of Example 14 was performed at 4 atm and 140° C. for 1 hour. The resulting product was p-xylylene glycol, and the yield and purity of p-xylylene glycol was 97% and 94%, respectively. The detailed reaction formulation and reaction conditions are listed in Table 1.
As shown in Table 1, where the reactant formulation and the reaction conditions were the same (e.g., Example 1, Example 6 and Example 9), Example 6 which used preparation system 200 had a higher yield and purity than Example 1 using preparation system 100. This is because in preparation system 200, the photo-bromination reaction and the substitution reaction were performed in separate reactors. In addition, compared to Example 6 which used preparation system 200, Example 9 using preparation system 300 had a higher yield and purity. This is because the photo-bromination reaction in preparation system 300 was performed continuously to allow sufficient reaction of all p-xylene. Accordingly, the yield and production efficiency were improved.
While the disclosure has been described by way of example and in terms of the preferred embodiments, it should be understood that the disclosure is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
| Number | Date | Country | Kind |
|---|---|---|---|
| 106127767 | Aug 2017 | TW | national |
This Application claims priority of U.S. Provisional Application No. 62/378,831, filed on Aug. 24, 2016 and Taiwan Patent Application No. 106127767, filed on Aug. 16, 2017, the entirety of which is incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 62378831 | Aug 2016 | US |
