JPS60104072A - Preparation of 4-methylimidazole - Google Patents
Preparation of 4-methylimidazoleInfo
- Publication number
- JPS60104072A JPS60104072A JP21282783A JP21282783A JPS60104072A JP S60104072 A JPS60104072 A JP S60104072A JP 21282783 A JP21282783 A JP 21282783A JP 21282783 A JP21282783 A JP 21282783A JP S60104072 A JPS60104072 A JP S60104072A
- Authority
- JP
- Japan
- Prior art keywords
- methylglyoxal
- water
- formaldehyde
- ammonium oxalate
- methylimidazole
- 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
Abstract
Description
【発明の詳細な説明】 本発明は４−メチルイミダゾールの製造法に関する。[Detailed description of the invention] The present invention relates to a method for producing 4-methylimidazole.
４−メチルイミダゾールの製造法としては米国特許第３
７１５３６５号に記載がある。該発明は強酸のアンモニ
ウム塩存在下にｐ！１７以下の水媒体中でグリオキザー
ル又はメチルグリオキザール（Ｐｙｒｕｖａｌｄｅｈｙ
ｄｅ）をホルムアルデヒドと反応させて、イミダゾール
類を製造するというもので、該強酸には特に硫酸及びシ
ュウ酸を挙げている。そしてメチルグリオキザールから
４−メチルイミダゾールを製造する具体例としては、メ
チルグリオキザール、硫酸アンモニウム及びホルマリン
を混合し、これにアンモニア水を滴下して反応せしめ、
その後水酸化カルシウムを添加して、アンモニアを飛散
させ、硫酸根を硫酸カルシウムとして沈澱させ、沈澱物
を濾別した後、脱水、蒸留して４−メチルイミダゾール
を得ると開示している。しかしながらその製品純度はガ
スクロ分析で７７％、収率は５９％であり、純度、収率
ともに満足なものとはいいがたい。The method for producing 4-methylimidazole is described in U.S. Patent No. 3.
It is described in No. 715365. In the present invention, p! Glyoxal or methylglyoxal (Pyruvaldehy
de) is reacted with formaldehyde to produce imidazoles, and sulfuric acid and oxalic acid are mentioned in particular as the strong acids. As a specific example of producing 4-methylimidazole from methylglyoxal, methylglyoxal, ammonium sulfate, and formalin are mixed, and aqueous ammonia is added dropwise to the mixture to cause a reaction.
The patent discloses that calcium hydroxide is then added to scatter ammonia, sulfate radicals are precipitated as calcium sulfate, and the precipitate is filtered, followed by dehydration and distillation to obtain 4-methylimidazole. However, the purity of the product was 77% according to gas chromatography analysis, and the yield was 59%, so it is difficult to say that both purity and yield are satisfactory.
木兄四人らは上記開示例において、硫酸アンモニウムの
代りにシュウ酸アンモニウムを用いてみたが、この場合
も収率、純度とも同様に思わしくない結果であった。４
−メチルイミダゾールは医薬の原料として利用されるが
、この程度の純度では使用できず、さらに精製を必要と
する。In the above-mentioned disclosed example, Kinei et al. tried using ammonium oxalate instead of ammonium sulfate, but in this case, the yield and purity were similarly unsatisfactory. 4
- Methylimidazole is used as a raw material for medicine, but it cannot be used at this level of purity and requires further purification.
木兄四人らは上記米国特許における開示例を検討する中
で、目的とする４−メチルイミダゾールのほかに２，４
−ジメチル体や二量体、さらには不明の重合物が副生じ
ていることを認め、これらの副生物はメチルグリオキザ
ールに対してシュウ酸アンモニウムとホルムアルデヒド
の組合わせで特定濃度で反応させる時は著しく減少し製
品純度を高めるばかりでなく、収率も向上することを見
出し本発明を完成させた。In addition to the target 4-methylimidazole, 2,4
- It was recognized that dimethyl forms, dimers, and even unknown polymers were produced as by-products, and these by-products were significantly reduced when methylglyoxal was reacted with a combination of ammonium oxalate and formaldehyde at a specific concentration. The inventors have completed the present invention by discovering that not only the product purity can be improved by reducing the amount of carbon dioxide, but also the yield can be improved.
すなわち本発明の目的はメチルグリオキザールを出発原
料とした高純度でしかも高収率の４−メチルイミダゾー
ルを工業的に容易に得ることであり。That is, an object of the present invention is to industrially easily obtain 4-methylimidazole of high purity and high yield using methylglyoxal as a starting material.
その構成はメチルグリオキザールにシュウ酸アンモニウ
ム及びホルムアルデヒドを水媒体中で反応させて、該水
の量を使用メチルグリオキザールの４〜３０倍としたこ
とを特徴とする４−メチルイミダゾールの製造法である
。Its structure is a method for producing 4-methylimidazole, characterized in that methylglyoxal is reacted with ammonium oxalate and formaldehyde in an aqueous medium, and the amount of water is 4 to 30 times the amount of methylglyoxal used.
本発明でいう反応系の水量とは使用さＪする各原料のも
つ結晶水又は含水分、或いは追加される水。The amount of water in the reaction system as used in the present invention refers to the water of crystallization or moisture contained in each raw material used, or the water added.
反応生成水等の総和を示し、この総水量が使用メチルグ
リオキザールの４〜３０倍になるように調整しなければ
ならない。例えば、各原料を単独或いは混合して水に溶
解又は分散して適宜濃度の水溶液とする場合は、総水量
が発明範囲内にあるようにする限り操作上有利な量にな
るよう自由に配水すればよい。総水量がメチルグリオキ
ザールに対して４倍以下になると副生物が多く生成し、
゛収率も急激に低下する。２倍以下では特にこの傾向が
著しい。１５倍以上になると収率的には変らないが、反
応速度が遅くなり、３０倍以上になると生産性や後処理
工程での問題が生ずるので総水量としてはメチルグリオ
キザールの５〜１５倍が好ましい。It shows the total amount of reaction product water, etc., and must be adjusted so that the total amount of water is 4 to 30 times the amount of methylglyoxal used. For example, when each raw material is dissolved or dispersed in water alone or in a mixture to form an aqueous solution of an appropriate concentration, water may be freely distributed to an operationally advantageous amount as long as the total amount of water is within the scope of the invention. Bye. If the total amount of water is less than 4 times the amount of methylglyoxal, many by-products will be produced.
゛Yield also decreases rapidly. This tendency is particularly remarkable when the ratio is less than 2 times. If the amount is 15 times or more, the yield will not change, but the reaction rate will be slow, and if it is more than 30 times, problems will occur in productivity or post-treatment steps, so the total amount of water is preferably 5 to 15 times that of methylglyoxal. .
本発明の製造法は特定水量中でメチルグリオキザールと
ホルムアルデヒド及びシュウ酸アンモニウムを接触させ
て５反応させるがその使用量は例えば当量で１：１：１
が好ましい。シュウ酸アンモニウムの過剰は不利ではな
いが、ホルムアルデヒドの過剰は副反応を促進し、不都
合である。反応温度は２０〜１００℃、好ましくは４０
〜８０℃である。In the production method of the present invention, methylglyoxal is brought into contact with formaldehyde and ammonium oxalate in a specific amount of water, and the reaction is carried out.
is preferred. Although an excess of ammonium oxalate is not disadvantageous, an excess of formaldehyde promotes side reactions and is disadvantageous. The reaction temperature is 20-100°C, preferably 40°C.
~80°C.
反応時間はその反応温度にもよるが２〜５時間で終了す
る。Although the reaction time depends on the reaction temperature, it is completed in 2 to 5 hours.
本発明において反応系の総水量を厳密に特定しても、各
原料を一時に混合した後温度を上げて反応させたり、各
原料を混合しておいて、ホルムアルデヒド又はシュウ酸
アンモニウムだけをあとから添加して行く方法を採ると
、副反応が著しく、純度、収率とも満足できる結果が得
られない。本発明方法効果をさらに発揮させるに好まし
い原料添加方法は以下に示すとおりである。Even if the total amount of water in the reaction system is strictly specified in the present invention, it is not possible to mix each raw material at once and then raise the temperature to react, or to mix each raw material and then add only formaldehyde or ammonium oxalate later. If the addition method is adopted, side reactions will be significant and results that are unsatisfactory in terms of purity and yield cannot be obtained. A preferable method of adding raw materials to further exhibit the effects of the method of the present invention is as shown below.
（１）シュウ酸アンモニウムとホルムアルデヒドの水溶
液中へ、メチルグリオキザールを添加する。(1) Add methylglyoxal to an aqueous solution of ammonium oxalate and formaldehyde.
（２）シュウ酸アンモニウム水溶液中へ、メチルグリオ
キザールとホルムアルデヒドの混合液又はそれぞれを同
時に添加する。(2) A mixture of methylglyoxal and formaldehyde, or each of them, is added simultaneously to an aqueous ammonium oxalate solution.
（３）先に用意した水中へ、メチルグリオキザールとホ
ルムアルデヒド、シュウ酸アンモニウムを同時に添加す
る。(3) Simultaneously add methylglyoxal, formaldehyde, and ammonium oxalate to the previously prepared water.
かくして反応を終了した反応系中には４−メチルイミダ
ゾールのシュウ酸塩が生成しており、例えば、反応系を
アルカリ性にして、溶媒で抽出した後、減圧蒸留する方
法、或いは反応系から減圧下、水を回収し、得られた４
−メチルイミダゾールのシュウ酸塩をそのまま、或いは
一旦濾過、アルコール等で洗浄した後、アルカリ性にし
て分解し、シュウ酸アルカリ塩を除去した後、減圧蒸留
する方法などによって４−メチルイミダゾールを分取す
る。After the reaction has ended, 4-methylimidazole oxalate is produced in the reaction system.For example, the reaction system can be made alkaline, extracted with a solvent, and then distilled under reduced pressure, or , water was collected and the obtained 4
- Methylimidazole oxalate is used as it is, or after it is filtered and washed with alcohol etc., it is made alkaline and decomposed, the alkaline oxalate is removed, and 4-methylimidazole is fractionated by distillation under reduced pressure. .
本発明の方法により得られた４−メチルイミダゾールは
特別な精製をしなくても純度９５％以上あリ、収率は７
５％を下ることはない。The 4-methylimidazole obtained by the method of the present invention has a purity of 95% or more without special purification, and the yield is 7.
It never falls below 5%.
本発明方法によ４しば原料メチルグリオキザールとして
ブ［１ピレングリコールの空気酸化による低純度品など
も有利に使用することもできる。プロピレンクリコール
の空気酸化によるメチルイミダゾ−ルはその製品水溶液
中には通常大量のプロピレングリコールを残存しており
、その他、副生物として、ホルムアルデヒド、１−ヒド
ロキシ−２−プロパノン、ギ酸、酢酸等が副柱するが、
これらを除くことなくそのまま使用しても、本発明方法
の効果が発現さ４して４−メチルイミダゾールの高純度
品を高収率で得ることができて、特別の精製手段を講す
る必要はない。In the method of the present invention, it is also possible to advantageously use a low-purity product obtained by air oxidation of butylpyrene glycol as the raw material methylglyoxal. Methylimidazole produced by air oxidation of propylene glycol usually leaves a large amount of propylene glycol in the product aqueous solution, and other by-products include formaldehyde, 1-hydroxy-2-propanone, formic acid, acetic acid, etc. Although it is a secondary pillar,
Even when used as is without removing these substances, the effect of the method of the present invention is manifested and a highly purified product of 4-methylimidazole can be obtained in high yield, and there is no need to take special purification measures. do not have.
本発明の方法により収率、純度が著るしく向上した理由
については未だ十分に解明されていないが特定原料の組
合わせ下に１反応系を特定希薄水溶液中で反応させるこ
と、また、各原料の添加順序を限定することにより、２
，４−ジメチル体や二量体又は重合体等の副生物の生成
が抑えられたものと推定される７
次に本発明について実施例でさらに詳しく説明する。The reason why the yield and purity are significantly improved by the method of the present invention is not fully understood yet, but it is important to note that the method of the present invention allows one reaction system to react in a specific dilute aqueous solution with a combination of specific raw materials, and that each raw material is By limiting the order of addition of 2
, 4-dimethyl, dimer, polymer, and the like was suppressed.7 Next, the present invention will be explained in more detail with reference to Examples.
実施例１
水８０ｍ１にシュウ酸アンモニウム６７、２ｇを仕込み
、分散させる。さらに３７％ホルムアルデヒド水溶液３
１．４ｇを注入し、５５℃まで加熱した。４２％メチル
グリオキザール７３．８ｇ （０，４３ｍｏｌ）を５５
〜６０°Ｃで１時間を要して、滴下した。２時間同温度
で保温した後、反応マスをサンプリングし、アルカリで
分解後、ガスクロ分析（内標法）で４−メチルイミダゾ
ールの含有率を分析し１反応直後の収率をめた。Example 1 67.2 g of ammonium oxalate is charged into 80 ml of water and dispersed. Furthermore, 37% formaldehyde aqueous solution 3
1.4g was injected and heated to 55°C. 73.8g (0.43mol) of 42% methylglyoxal in 55%
The dropwise addition took 1 hour at ~60°C. After being kept at the same temperature for 2 hours, the reaction mass was sampled, decomposed with an alkali, and analyzed for the content of 4-methylimidazole by gas chromatography (internal standard method) to calculate the yield immediately after one reaction.
その結果を表１に示す。The results are shown in Table 1.
ガスクロ分析法：島津ＧＣ−７Ａを使用し、カラ、ム：
丁ＥＮＡＸ ＧＣ６０／８０ｍｅｓｈ、カラム温度＝１
９０℃、インジェクション温度＝２５０℃、キャリヤー
ガス：窒素７０ｍ１／ｍｉｎ、検出器： ＦＤＩ、内部
標準ニジエチレングリコールの条件で分析した。Gas chromatography method: Using Shimadzu GC-7A, column:
DingENAX GC60/80mesh, column temperature = 1
The analysis was conducted under the following conditions: 90°C, injection temperature = 250°C, carrier gas: nitrogen 70ml/min, detector: FDI, and internal standard diethylene glycol.
実施例２
実施例１において水８０ｍ１の代りに１２９ｍ１用いた
以外実施例１と同様にした。結果を表１に赤す。Example 2 The procedure of Example 1 was repeated except that 129 ml of water was used instead of 80 ml of water in Example 1. The results are shown in Table 1.
実施例３〜５
実施例１において水８０耐の代りに水１８１．７１９１
．８６７ｍ１用いた以外実施例１と同様にした。結果を
表１に示す。Examples 3 to 5 Water 181.7191 instead of water 80 resistance in Example 1
．． The procedure was the same as in Example 1 except that 867 ml was used. The results are shown in Table 1.
比較例１〜２
実施例１において水８０ ｍ ｌの代りに０．５０＋ｎ
ｌ使用し、以下実施例】と同様にして、４−メチルイミ
ダゾールの収率をめた。その結果を表１に示す。Comparative Examples 1-2 0.50+n instead of 80 ml of water in Example 1
The yield of 4-methylimidazole was determined in the same manner as in Example below. The results are shown in Table 1.
表１
実施例１〜５及び比較例１〜２の結果から反応系を水で
希釈するに従って収率が向上することが判る。Table 1 From the results of Examples 1 to 5 and Comparative Examples 1 to 2, it can be seen that the yield improves as the reaction system is diluted with water.
実施例６
水１５０ｍ１にシュウ酸アンモニウム６７．２ｇを仕込
み。Example 6 67.2 g of ammonium oxalate was added to 150 ml of water.
分散させる。さらに３７％ホルムアルデヒド水溶液３１
．４ｇを注入し、５５℃まで加熱した。４２％メチルク
′リオキザール７：３．８ｇ（０，４３ｍｏｌ）を５５
〜６０℃で１時間を要して滴下した。２時間同温度で保
温した後、減圧下、水を回収した。得られたシュウ酸塩
を少量のアルコールで洗った後、２５％アンモニア水で
分解し、冷却し、析出したシュウ酸アンモニウムを濾別
し、少量のメタノールで洗い、母液、洗液を合わせ、減
圧下脱水、つづいて減圧蒸留して１３０〜１．４０℃／
７ｕｖ＋ｌ１ｇの留分をとり純度９８．５％の４−メチ
ルイミダゾール２８．１ｇを得た。収率７８．３％比較
例３
水１５０耐にシュウ酸アンモニウム６７．２ｇを込み、
分散させる。４２％メチルグリオキザール７３．８ｇ（
０゜４３ｍｏ１．）を注入し５５℃まで加熱した。３７
％ホルムアルデヒド水溶液３１．４ｇを５５〜６０℃で
１時間を要して、滴下した。２時間同温度で保温した。disperse. Furthermore, 37% formaldehyde aqueous solution 31
．． 4g was injected and heated to 55°C. 42% Methyl Kryoxal 7: 3.8g (0.43mol) in 55%
The dropwise addition took 1 hour at ~60°C. After keeping at the same temperature for 2 hours, water was collected under reduced pressure. After washing the obtained oxalate with a small amount of alcohol, it was decomposed with 25% aqueous ammonia, cooled, and the precipitated ammonium oxalate was separated by filtration, washed with a small amount of methanol, the mother liquor and the washing liquid were combined, and the mixture was decompressed under reduced pressure. Lower dehydration followed by vacuum distillation to 130-1.40℃/
A fraction of 7 uv + 1 g was taken to obtain 28.1 g of 4-methylimidazole with a purity of 98.5%. Yield 78.3% Comparative Example 3 67.2 g of ammonium oxalate was added to 150-proof water.
disperse. 42% methylglyoxal 73.8g (
0°43mo1. ) was injected and heated to 55°C. 37
% formaldehyde aqueous solution was added dropwise at 55 to 60°C over 1 hour. It was kept at the same temperature for 2 hours.
以後、実施例６と同様に処理して、純度９６，７％の４
−メチルイミダゾール２０．１ｇを得た。収率５５％で
あった。Thereafter, the same treatment as in Example 6 was carried out to obtain 4 with a purity of 96.7%.
-20.1 g of methylimidazole was obtained. The yield was 55%.
比較例４
水１５０ｍ１に３７％ホルムアルデヒド水溶液３１．４
ｇ及び４２％メチルグリオキザール７３．８ｇ（０，４
３ｍｏｌ）を溶解し、５５°Ｃまで加熱した。シュウ酸
アンモニウム６７．２ｇを５５・〜６０℃で１時間を要
して、添加した。２時間同温度で保温した。以後、実施
例６と同様に処理して、純度９７．０％の４−メチルイ
ミダゾール１８゜２ｇを得た。収率５０％であった。Comparative example 4 37% formaldehyde aqueous solution 31.4 in 150ml of water
g and 42% methylglyoxal 73.8 g (0,4
3 mol) was dissolved and heated to 55°C. 67.2 g of ammonium oxalate was added over a period of 1 hour at 55-60°C. It was kept at the same temperature for 2 hours. Thereafter, the same treatment as in Example 6 was carried out to obtain 18.2 g of 4-methylimidazole with a purity of 97.0%. The yield was 50%.
実施例７
水１８１ｍ１にシュウ酸アンモニウム６７．２ｇを仕込
み、５５℃まで昇温した。これに３７％ホルムアルデヒ
ド水溶液３１．４ｇと４２％メチルグリオキザール７３
．８ｇ（０゜４３ｍｏｌ）混合液を５５〜６０℃で１時
間を要して滴下した。２時間同温度で保温した。以後、
実施例６と同様に処理して、純度９９．２％の４−メチ
ルイミダゾール２７．８ｇを得た。収率７８％であった
。Example 7 67.2 g of ammonium oxalate was added to 181 ml of water, and the temperature was raised to 55°C. Add to this 31.4g of 37% formaldehyde aqueous solution and 73g of 42% methylglyoxal.
．． 8 g (0°43 mol) of the mixed solution was added dropwise at 55 to 60° C. over 1 hour. It was kept at the same temperature for 2 hours. From then on,
The same treatment as in Example 6 was carried out to obtain 27.8 g of 4-methylimidazole with a purity of 99.2%. The yield was 78%.
実施例８
水８０＋ｕｌにシュウ酸アンモニウム６７．２ｇを溶解
し、別に、３７％ホルムアルデヒド水溶液３１．４ｇと
４２％メチルグリオキザール７３．８ｇ（０，４３＋ｏ
ｏｌ）を用意し。Example 8 67.2g of ammonium oxalate was dissolved in 80+ul of water, and separately 31.4g of 37% formaldehyde aqueous solution and 73.8g of 42% methylglyoxal (0.43+o
Prepare ol).
加温された水１５０ｍ１中に、５５〜６０°Ｃを保ちな
がら、この３者をそれぞれ独立にかつ同時に、１時間を
要して滴下した。２時間同温度で保温した。以後、実施
例６と同様に処理して、純度９９．１％の４−メチルイ
ミダゾール２７．８ｇを得た。収率７８％であった。These three components were individually and simultaneously added dropwise into 150 ml of heated water over a period of 1 hour while maintaining the temperature at 55 to 60°C. It was kept at the same temperature for 2 hours. Thereafter, the same treatment as in Example 6 was carried out to obtain 27.8 g of 4-methylimidazole with a purity of 99.1%. The yield was 78%.
特許出願人 田岡化学工業株式会社Patent applicant: Taoka Chemical Industry Co., Ltd.
Claims (5)
びホルムアルデヒドを水媒体中で反応させ、該水の量を
使用メチルグリオキザールの４〜３０倍としたことを特
徴とする４−メチルイミダゾールの製造法。(1) A method for producing 4-methylimidazole, characterized in that methylglyoxal, ammonium oxalate, and formaldehyde are reacted in an aqueous medium, and the amount of water is 4 to 30 times the amount of methylglyoxal used.
る特許請求の範囲第１項記載の製造法。(2) The production method according to claim 1, wherein the amount of water is 5 to 15 times that of methylglyoxal.
溶液中へ、メチルグリオキザールを添加して反応させる
ことからなる特許請求の範囲第１項記載の製造法。(3) The manufacturing method according to claim 1, which comprises adding methylglyoxal to an aqueous solution of ammonium oxalate and formaldehyde and causing the reaction.
キザールとホルムアルデヒドの混合液又はそれぞれを同
時に添加して反応させることからなる特許請求の範囲第
１項記載の製造法。(4) The production method according to claim 1, which comprises adding a mixture of methylglyoxal and formaldehyde, or each of them simultaneously, to an aqueous ammonium oxalate solution and reacting them.
ルムアルデヒドの混合液と同時にシュウ酸アンモニウム
を添加するか又はメチルグリオキザール、ホルムアルデ
ヒド、シュウ酸アンモニウムをそれぞれ同時に添加して
反応させることからなる特許請求の範囲第１項記載の製
造法。(5) Claims consisting of adding ammonium oxalate to the previously prepared water at the same time as a mixture of methylglyoxal and formaldehyde, or adding methylglyoxal, formaldehyde, and ammonium oxalate simultaneously and causing a reaction. The manufacturing method described in paragraph 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21282783A JPH0244468B2 (en) | 1983-11-12 | 1983-11-12 | 44MECHIRUIMIDAZOORUNOSEIZOHO |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21282783A JPH0244468B2 (en) | 1983-11-12 | 1983-11-12 | 44MECHIRUIMIDAZOORUNOSEIZOHO |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60104072A true JPS60104072A (en) | 1985-06-08 |
| JPH0244468B2 JPH0244468B2 (en) | 1990-10-04 |
Family
ID=16629013
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21282783A Expired - Lifetime JPH0244468B2 (en) | 1983-11-12 | 1983-11-12 | 44MECHIRUIMIDAZOORUNOSEIZOHO |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0244468B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1060470C (en) * | 1997-01-10 | 2001-01-10 | 中国石油化工总公司 | Process for preparing 4-methylimidazole |
| CN1060471C (en) * | 1997-01-10 | 2001-01-10 | 中国石油化工总公司 | Process for preparing 4-methylimidazole |
| US6177575B1 (en) * | 1998-06-12 | 2001-01-23 | E. I. Du Pont De Nemours And Company | Process for manufacture of imidazoles |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2819365B2 (en) * | 1992-05-28 | 1998-10-30 | キヤノン株式会社 | Image forming device |
-
1983
- 1983-11-12 JP JP21282783A patent/JPH0244468B2/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1060470C (en) * | 1997-01-10 | 2001-01-10 | 中国石油化工总公司 | Process for preparing 4-methylimidazole |
| CN1060471C (en) * | 1997-01-10 | 2001-01-10 | 中国石油化工总公司 | Process for preparing 4-methylimidazole |
| US6177575B1 (en) * | 1998-06-12 | 2001-01-23 | E. I. Du Pont De Nemours And Company | Process for manufacture of imidazoles |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0244468B2 (en) | 1990-10-04 |
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