CN1126751C - Method of reducing color number of benzene anhydride - Google Patents
Method of reducing color number of benzene anhydride Download PDFInfo
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- CN1126751C CN1126751C CN 00111283 CN00111283A CN1126751C CN 1126751 C CN1126751 C CN 1126751C CN 00111283 CN00111283 CN 00111283 CN 00111283 A CN00111283 A CN 00111283A CN 1126751 C CN1126751 C CN 1126751C
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- China
- Prior art keywords
- phthalic anhydride
- gac
- anhydride
- color number
- benzene
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Abstract
The present invention discloses a method for reducing color number of benzene anhydride with activated carbon. The activated carbon is granular, and can adsorb benzoic anhydride by a fixed bed or can adsorb benzoic anhydride by a stirring vessel. Compared with the other processing methods, the present invention has the characteristics of simple operation, extensive working range, low cost, no adverse side effect, etc.
Description
Technical field
The present invention relates to a kind of method that reduces color number of benzene anhydride, comprise sorbent material and using method thereof.
Background technology
O-Xylol air oxidation process (adjacent method) is the main method of producing phthalic anhydride at present, in this processing method, with the prolongation of the use of high loading catalyzer and catalyzer duration of service, the quality of phthalic anhydride product tends to variation gradually, shows that mainly molten color number, thermostability look number raise.This mainly is because oxidizing reaction is complete inadequately, has generated more intermediate products such as phthalide, has influenced the look number of phthalic anhydride.For addressing this problem, the general both at home and abroad at present way that adds rearmounted reactor that adopts is further reacted the intermediate product of generation; Or the method that adds additive when adopting thermal treatment removes objectionable impurities, adopts as the flat 6-145161 of Japanese Patent to add metal phosphate; United States Patent (USP) 4,165,324 add alkali metal hydroxide, all can effectively reduce the content of phthalide in the raw phthalic anhydride.By contrast, add rearmounted reactor cost height, operation easier is big; And in the additive method,, so easily cause tower tray or tower still pipeline to stop up during the rectifying phthalic anhydride because the additive that adds when raw phthalic anhydride thermal treatment generally all is inorganic salt.
Summary of the invention
The present invention adopts and to make phthalic anhydride and the contacted method of gac, makes the objectionable impurities that influence phthalic anhydride molten color number and thermostability look number in the charcoal absorption phthalic anhydride, thereby reaches the purpose of reduction phthalic anhydride product look number (comprise molten color number with thermostability look number).
In adjacent method phthalic anhydride was produced, the raw phthalic anhydride that reaction generates (being called weathering process) after certain hour thermal treatment is stable was carried out rectifying, ties sheet then and is packaged into product.Before rectifying, gac can be contacted with raw phthalic anhydride after the thermal treatment, reduce content of harmful in the raw phthalic anhydride, thereby make phthalic anhydride after rectifying, the content of detrimental impurity is lower than the foreign matter content in the phthalic anhydride that direct rectifying obtains without activated carbon treatment, thereby reduces color number of benzene anhydride.
Another kind method is that gac is contacted with phthalic anhydride after the rectifying, and absorption objectionable impurities wherein is to reduce color number of benzene anhydride.
When the present invention used the activated carbon treatment phthalic anhydride, temperature should be higher than the fusing point (130 ℃) of phthalic anhydride, is liquid state to guarantee phthalic anhydride.When this temperature can be respectively raw phthalic anhydride or refining benzene acid anhydride according to the object of handling, the service temperature (being generally 130～300 ℃) before and after its technical process and decide only otherwise the operation of influence front and back technology, and helped energy-conservation getting final product.
The present invention both can adopt the Static Adsorption form of gac, also can adopt the dynamic adsorption form.Static Adsorption can adopt the ADSORPTION IN A FIXED BED form, and dynamic adsorption can adopt still formula flow process to finish.Wherein ADSORPTION IN A FIXED BED is about to gac and is contained in the fixed-bed adsorber, and phthalic anhydride is from wherein flowing through.During practical application, can adopt the alternately absorption of two adsorbers, regeneration, at this moment, can adopt mean particle size is the gac of 0.1～10mm.The duration of contact of phthalic anhydride and gac is long more, and decolorizing effect is good more, generally should be in 0.1min～10h scope.
Still formula absorption is that gac enters stirring tank with phthalic anhydride, two kinds of material contacts and in still, stay for some time after leave, gac recycles after waiting method and phthalic anhydride separates after filtration.Still have decoloring ability preferably as the gac after separating, can directly recycle, otherwise recycle after should regenerating.Gac can adopt fine particle, and median size is 1 μ m～1mm.The weight ratio of gac and phthalic anhydride can be 0.1～200%wt in the stirring tank, and this ratio is big more, and the mean residence time of phthalic anhydride in still can be short more.The residence time is generally the weight ratio that 0.1min～10h multiply by interior phthalic anhydride of still and gac.
Characteristics of the present invention be easy and simple to handle, operating restraint wide (both can handle raw phthalic anhydride, and can handle the phthalic anhydride after the rectifying again), cost low, do not have a bad side effect.
Embodiment
The present invention will be further described to use embodiment and Comparative Examples below:
Comparative Examples 1: get an amount of phthalic anhydride product (taking from full scale plant), in there-necked flask, be heated to 180 ℃, respectively sampling analysis molten color number and thermostability look number behind constant temperature stir process 0h, 1h, 3h, the 5h, the analysis of look number is undertaken by GB GB/T15336-94.The result is as shown in table 1.
Color number of benzene anhydride when table 1 does not add activated carbon treatment
| Treatment time (h) | Molten color number | Thermostability look number |
| 0 | 60 | 200 |
| 1 | 70 | 270 |
| 3 | 120 | 350 |
| 5 | 150 | 480 |
Embodiment 1: adding the 1%wt median size in the phthalic anhydride product identical with Comparative Examples 1 is 20～40 purpose gacs, in there-necked flask, be heated to 180 ℃, respectively sampling analysis molten color number and thermostability look number behind constant temperature stir process 0h, 1h, 3h, the 5h, the analysis of look number is undertaken by GB GB/T15336-94.The result is as shown in table 2.
Color number of benzene anhydride when table 2 adds activated carbon treatment
| Treatment time (h) | Molten color number | Thermostability look number |
| 0 | 60 | 200 |
| 1 | 60 | 250 |
| 3 | 65 | 160 |
| 5 | 45 | 140 |
Compare with Comparative Examples 1, as seen add activated carbon treatment after the identical time, with do not add activated carbon treatment and compare, the molten color of product number and thermostability look number obviously reduce, even be lower than the look number of phthalic anhydride product before the heat treated, illustrate that method of the present invention has good decolorization to phthalic anhydride, and produced the beyond thought decolorizing effect of those of ordinary skills.
Claims (8)
1, a kind of method that reduces color number of benzene anhydride is characterized in that making phthalic anhydride to contact with gac, and the contact temperature is 130～300 ℃.
2, method according to claim 1 is characterized in that gac is placed in the fixed-bed adsorber, and phthalic anhydride flows through from adsorber, and gac is granular, and median size is 0.1～10mm.
3, method according to claim 2, be 0.1min～10h the duration of contact that it is characterized in that described phthalic anhydride and gac.
4, method according to claim 2 is characterized in that fixed-bed adsorber adopts the form of two parallel connections, and absorption and regeneration hocket.
5, method according to claim 1 is characterized in that gac contacts in stirring tank with phthalic anhydride, then phthalic anhydride is separated with gac, and gac is a fine particle, and median size is 1 μ m～1mm.
6, method according to claim 5 is characterized in that gac content is 0.1～200%wt of phthalic anhydride content, and mean residence time is the weight ratio that 0.1min～10h multiply by phthalic anhydride and gac in the still in still.
7,, it is characterized in that described phthalic anhydride is the phthalic anhydride after the rectifying according to claim 1,2 or 5 described methods.
8,, it is characterized in that described phthalic anhydride is for through Overheating Treatment, without the raw phthalic anhydride of rectifying according to claim 1,2 or 5 described methods.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 00111283 CN1126751C (en) | 2000-08-09 | 2000-08-09 | Method of reducing color number of benzene anhydride |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 00111283 CN1126751C (en) | 2000-08-09 | 2000-08-09 | Method of reducing color number of benzene anhydride |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1336368A CN1336368A (en) | 2002-02-20 |
| CN1126751C true CN1126751C (en) | 2003-11-05 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 00111283 Expired - Fee Related CN1126751C (en) | 2000-08-09 | 2000-08-09 | Method of reducing color number of benzene anhydride |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1126751C (en) |
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2000
- 2000-08-09 CN CN 00111283 patent/CN1126751C/en not_active Expired - Fee Related
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| Publication number | Publication date |
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| CN1336368A (en) | 2002-02-20 |
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