GB2025941A - Purification of Aniline - Google Patents
Purification of Aniline Download PDFInfo
- Publication number
- GB2025941A GB2025941A GB7916682A GB7916682A GB2025941A GB 2025941 A GB2025941 A GB 2025941A GB 7916682 A GB7916682 A GB 7916682A GB 7916682 A GB7916682 A GB 7916682A GB 2025941 A GB2025941 A GB 2025941A
- Authority
- GB
- United Kingdom
- Prior art keywords
- aniline
- phosphoric acid
- crude aniline
- ppm
- cyclohexanone
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
- C07C209/30—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds
- C07C209/32—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds by reduction of nitro groups
- C07C209/36—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds by reduction of nitro groups by reduction of nitro groups bound to carbon atoms of six-membered aromatic rings in presence of hydrogen-containing gases and a catalyst
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
- C07C209/82—Purification; Separation; Stabilisation; Use of additives
- C07C209/84—Purification
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
- C07C209/82—Purification; Separation; Stabilisation; Use of additives
- C07C209/86—Separation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C211/00—Compounds containing amino groups bound to a carbon skeleton
- C07C211/43—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton
- C07C211/44—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton having amino groups bound to only one six-membered aromatic ring
- C07C211/45—Monoamines
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C211/00—Compounds containing amino groups bound to a carbon skeleton
- C07C211/43—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton
- C07C211/44—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton having amino groups bound to only one six-membered aromatic ring
- C07C211/45—Monoamines
- C07C211/46—Aniline
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C211/00—Compounds containing amino groups bound to a carbon skeleton
- C07C211/43—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton
- C07C211/44—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton having amino groups bound to only one six-membered aromatic ring
- C07C211/49—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton having amino groups bound to only one six-membered aromatic ring having at least two amino groups bound to the carbon skeleton
- C07C211/50—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton having amino groups bound to only one six-membered aromatic ring having at least two amino groups bound to the carbon skeleton with at least two amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C211/00—Compounds containing amino groups bound to a carbon skeleton
- C07C211/43—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton
- C07C211/44—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton having amino groups bound to only one six-membered aromatic ring
- C07C211/49—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton having amino groups bound to only one six-membered aromatic ring having at least two amino groups bound to the carbon skeleton
- C07C211/50—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton having amino groups bound to only one six-membered aromatic ring having at least two amino groups bound to the carbon skeleton with at least two amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton
- C07C211/51—Phenylenediamines
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C211/00—Compounds containing amino groups bound to a carbon skeleton
- C07C211/43—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton
- C07C211/54—Compounds containing amino groups bound to a carbon skeleton having amino groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton having amino groups bound to two or three six-membered aromatic rings
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
Abstract
A process for reducing the cyclohexanone content of crude aniline that has been prepared by the catalytic hydrogenation of nitrobenzene comprising treating the crude aniline with phosphoric acid or an alkyl or chloroalkyl ester thereof.
Description
SPECIFICATiON
Chemical Process
This invention relates to a chemical process and more particularly to a process for reducing the level of impurities present in crude aniline that has been prepared by the conventional hydrogenation of nitrobenzene.
The manufacture of aniline by the catalytic hydrogenation of nitrobenzene is an established industrial process. The conversion of nitrobenzene to aniline takes place in very high yields but, in addition to the main reaction, some unwanted side reactions take place resulting in the formation of impurities. One of these impurities is cyclohexanone which is difficult to remove from the aniline by normal physical methods such as distillation.
It has now been found that the cyclohexanone content of the aniline can be reduced by a chemical treatment as hereinafter described.
Thus, according to the invention, there is provided a process for reducing the cyclohexanone content of crude aniline that has been prepared by the catalytic hydrogenation of nitrobenzene comprising treating the crude aniline with phosphoric acid or an alkyl or chioroalkyl ester thereof.
The crude aniline treated according to the invention may have been prepared by any batch or continuous process involving the catalytic hydrogenation of nitrobenzene. Catalysts involved in the hydrogenation include Raney nickel, palladium on charcoal or supported nickel, cobalt or copper and especially nickel-on-kieselguhr.
One continuous process for the manufacture of aniline by the liquid phase catalysed hydrogenation of nitrobenzene is described in our United Kingdom Patent Specification No. 982,903 and is characterised in that the concentration of aniline in the liquid phase is not less than 95% by weight and in that the hydrogenation is conducted at the apparent boiling point of the reaction mixture at a pressure not exceeding 10 atmospheres, at least some of the heat of the reaction being removed by allowing the reaction mixture to evaporate, the vapours being condensed, water separated from the condensate and when necessary sufficient of the condensed aniline being returned to the reactor to maintain steady conditions therein.
The product of the hydrogenation process is crude aniline usually containing some water and small amounts of cyclohexanone and other impurities. In accordance with the invention, this crude aniline is treated with phosphoric acid or an alkyl, chloroalkyl or acid alkyl ester thereof at ambient or elevated temperatures. it is believed that during the treatment the cyclohexanone reacts with aniline to form cyclohexylidene aniline. The water which is also formed in this reaction can be removed by azeotropic distillation and accordingly it is convenient to carry Out the treatment at the boiling point of the crude aniline using normal or reduced pressures.
The amount of phosphoric acid or ester thereof used in the treatment can be varied over a wide range, for example 10 ppm to 5%. An amount of about 50 ppm on the weight of crude aniline is suitable. The preferred agent is phosphoric acid. It may be employed as an aqueous solution of any convenient strength, for example 10% aqueous, up to the highest strength polyphosphoric acid available.
At the end of the treatment the purified aniline may bs Isolated by a conventional distillation procedure.
The treatment can be carried out in completely conventional equipment, and may be operated as batch or continuous process.
The invention is illustrated but not limited by the following Examples 8, 13-1 6, 18, 1 9 and 21 in which all parts and percentages are by weight. The remaining Examples are Included for comparison.
Example 1
Aniline containing 1% of cyclohexanone as impurity was heated at 1 300C for 90 minutes and the increase in water content of the mixture found and compared with the maximum increase theoretically possible according to the equation
In absence of catalyst the water content change indicated 27% of the maximum possible amount to have been formed.
Examples 2-10 This experiment was repeated in the presence of 50 ppm of a number of possible catalysts with the results shown.
Water formed:
% of theoretical
Example Agent maximum amount
2 Boric acid 40.5
3 2-Ethylhexoic acid 67.6
4 Formic acid 27.0
5 Citric acid 67.6
6 Benzenesulphonic acid 54.1
7 Sulphuric acid 33.8
8 85% Phosphoric acid 94.6
9 Methane sulphonic acid 60.8
10 Potassium hydroxide 40.5
These results clearly demonstrate the effectiveness of phosphoric acid in promoting the removal of cyclohexanone by reaction with aniline.
Examples 11-16 Aniline containing 1,000 ppm of cyclohexanone as impurity was heated at 1 320C in the presence of 50 ppm of a catalyst and samples analysed at intervals for cyclohexanone by GLC.
Time to 50 ppm
Example Agent cyclohexanone
11 None > 90 minutes
12 Triphenylphosphoramide 65
13 Triethyl phosphate 20
14 85% Phosphoric acid 30
15 Tris-(chloropropyl) phosphate 30
16 Tris-(chloroethyl) phosphate 20
Examples 17-19 Aniline containing 1,000 ppm of cyclohexanone as impurity was heated at 11 00C and 81 mm Hg pressure so that the aniline distilling from the flask was condensed and any water present removed before return of aniline to the reactor using a Dean and Stark separator. cycloHexanone content was determined by GLC at intervals.
Time to 50 ppm
Example Agent (50 ppm) cyclohexanone
17 None 70 minutes
18 Triethyl phosphate 42
19 85% Phosphoric acid 30
Examples 20-21 Similar experiments at 1 800C/760 mm also under azeotropic drying conditions gave simiiar results.
Time to 50 ppm
Example Agent cyclohexanone
20 None 20 minutes
21 85% phosphoric acid 8
Claims (6)
1. A process for reducing the cyclohexangne content of crude aniline that has been prepared by
the catalytic hydrogenation of nitrobenzene comprising treating the crude aniline with phosphoric acid
or an alkyl or chloroalkyl ester thereof.
2. A process as claimed in claim 1 wherein the treatment is carried out at the boiling point of the
crude aniline using normal or reduced pressures.
3. A process as claimed in claim 1 wherein the phosphoric acid or ester thereof is used in an
amount of from 10 ppm to 5% based on the weight of crude aniline.
4. A process as claimed in claim 3 wherein the phosphoric acid or este;thereof is used in an
amount of approximately 50 ppm on the weight of crude aniline.
5. A process as claimed in claim 1 substantially as hereinbefore described with reference to any
one of Examples 8, 13-16, 18, t9 and 21.
6. Aniline whenever treated by a process claimed in any one of the preceding claims.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7916682A GB2025941B (en) | 1978-06-08 | 1979-05-14 | Purification of aniline |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7826546 | 1978-06-08 | ||
| GB7916682A GB2025941B (en) | 1978-06-08 | 1979-05-14 | Purification of aniline |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2025941A true GB2025941A (en) | 1980-01-30 |
| GB2025941B GB2025941B (en) | 1982-07-07 |
Family
ID=26267931
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7916682A Expired GB2025941B (en) | 1978-06-08 | 1979-05-14 | Purification of aniline |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2025941B (en) |
-
1979
- 1979-05-14 GB GB7916682A patent/GB2025941B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB2025941B (en) | 1982-07-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3804082B2 (en) | Purification method of aniline | |
| EP0632013B1 (en) | Method for decolorization of alkanolamines | |
| CS203171B2 (en) | Method of processing waste products at the production of diphenylolpropane | |
| US4207262A (en) | Chemical process for reducing the cyclohexanone content of crude aniline | |
| US9771291B2 (en) | Process for working up waste water from nitrobenzene preparation | |
| US4381222A (en) | Process for the distillative separation of tertiary alkyl hydroperoxides and ditertiary alkyl peroxides | |
| CA2391715C (en) | Purification method of cyclohexanone-oxime | |
| JPH04308548A (en) | Method of purifying carboxylic acid | |
| KR102176381B1 (en) | Method for reprocessing wastewater from nitrobenzene production | |
| US5399776A (en) | Purification of acetone | |
| US3252997A (en) | Purification of sulfolane compounds | |
| DE60313950T2 (en) | METHOD FOR PRODUCING AN ALKYLARYLHYDROPEROXIDE-CONTAINING PRODUCT | |
| GB2025941A (en) | Purification of Aniline | |
| JPS6050171B2 (en) | Manufacturing method of resorcinol | |
| US4570019A (en) | Method of preparing polyethylene polyamines having improved color | |
| US4241229A (en) | Recovery of nitrated aromatic compounds from nitration wash liquors | |
| US3280168A (en) | Catalytic acrylonitrile production | |
| US4855516A (en) | Method of manufacturing 2-propyn-1-ol | |
| JP3856872B2 (en) | Method for producing high purity carbon monoxide | |
| EP0058962B1 (en) | Method of preparing polyethylene polyamines having improved color | |
| US4314940A (en) | Method for the purification of raw caprolactam | |
| GB2110681A (en) | Process for treating spent sulfuric acid streams from the olefin hydration reaction | |
| US2798035A (en) | Manufacture of acrylonitrile | |
| EP0216351A2 (en) | Process for purification of oxidation reaction mixture | |
| JPH04169545A (en) | Purification of cresol |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |