| 氏名 | 菅野 修一 |
|---|---|
| 所属 | 家政学部 家政学科 |
| 職名 | 教授 |
| 学位 | 工学博士 |
| 専門分野 | 高分子合成・ラジカル重合開始剤・イオン液体 |
| 主な担当教科 | 専門研究(ポリマーケミストリー)・有機化学・化学・被服繊維学・被服材料学 |
研究題目
- 新規なラジカル重合開始剤としてのイオン液体に関する研究
- 種々のアルキルホウ素化合物の特殊なラジカル重合開始能に関する研究
- 新機能を発現させる新規なレドックス重合開始剤の開発
- 新規なボラン錯体の合成と、その特殊なラジカル重合開始能に関する研究
最近の主な業績
Ⅰ.研究活動
| 著書・論文等の名称 | 単著・共著 | 発行又は発表の年月（西暦） | 発行所、発表雑誌(及び巻、号数)等の名称 | 共著者名 | 掲載頁 |
|---|---|---|---|---|---|
| 一部酸化アルキルボランであるブトキシジブチルボランを開始剤とするメタクリル酸メチルの重合挙動 | 単 | 2022年 | 2012年 東北生活文化大学教職課程センター報, Vol.6 (2022) | 12-28 | |
| Unique Radical Polymerization of Methyl Methacrylate Initiated with B-Methoxy-9-borabicyclo[3.3.1]nonane | 単 | 2022年 | 東北生活文化大学紀要, 52 (2021) | 43-52 | |
| 新規なラジカル重合開始剤としてのイオン液体の可能性 | 単 | 2021年 | 技術情報教会『重合開始剤・硬化剤・架橋剤の選び方、使い方とその事例』 | 94-116 | |
| 空気雰囲気下B-メトキシ-9-ボラビシクロ[3.3.1]ノナンを開始剤とするスチレンのラジカル重合 | 単 | 2021年 | 東北生活文化大学教職課程センター報, Vol.5 (2021) | 4-19 | |
| Polymerization of Methyl Acrylate Initiated with B-Methoxy-9-borabicyclo[3.3.1]nonane Under Air Atmosphere | 単 | 2021年 | 東北生活文化大学紀要, 51 (2020) | 35-44 | |
| ピロリジニウムイオン液体である1-ブチル-1-メチルピロリジニウムトリス(ペンタフルオロエチル)トリフルオロフォスフェート及び1-ブチル-1-メチルピロリジニウム トリフルオロメチルスルフォネートのビニル重合開始能に関するスクリーニングテスト | 単 | 2020年 | 東北生活文化大学教職課程センター報, Vol.4 (2020) | 8-15 | |
| Screening Test for Imidazolium Ionic Liquids in Regard to the Initiating Ability of Vinyl Polymerization of Methyl Acrylate | 単 | 2020年 | 東北生活文化大学紀要, 50 (2019) | 33-42 | |
| Unique Initiating Ability of Radical Polymerization in Regard to Diethylmetoxyborane as Dialkylalkoxyborane | 単 | 2019年 | 東北生活文化大学紀要, 49 (2018) | 57-66 | |
| Challenges for Unique Application of Ionic Liquids as a Novel Initiator of Radical Polymerization | 単 | 2014年 | Molecular Crystals & Liquid Crystals, | 3-19 | |
| New Aspects of Ionic Liquids as a Novel Initiator of Radical Polymerization | 単 | 2012年 | Molecular Crystals & Liquid Crystals, | 61-73 |
＊ここに示した業績は、著者の業績の一部として、ごく最近の当大学の紀要及び教育センター年報を中心に記載した。尚、紀要については国立国会図書館に収蔵されているので、著者の業績の概要は各紀要のReferenceを御参照いただければ幸いである。著者の業績は英文ジャーナル誌・日本国特許・国内専門誌・国際会議プロシーディング・国内各種学会予稿集など数百にわたる。
Ⅱ.教育活動
| 教育実践上の主な業績 | 年月日 | 概要 |
|---|---|---|
| Radical Polymerization Initiated with Ionic Liquids | Programme and Abstreacts of 26th EUCHEM Conference on Molten Salts and Ionic Liquids, (2016) 316.／(Hotel Savoyen / Praha, Vienna, Austria) | It is generally known as one of the representative characteristics of ionic liquids that they are stable thermally and chemically. Therefore, it is not considered the common sense that the use of ionic liquids as an initiator of polymerization. However, it is also a fact to keep much possibility that ionic liquids can also be applied in the field which isn’t reported so far. In fact, up to now, although its polymerization mechanism has not been elucidated, the author discovered a radical initiating ability of polymerization about certain ionic liquids. Under such circumstances, in this presentation, the author reports the basic experimental results of the polymerization initiating ability about some kinds of ionic liquids. |
| Unique Reaction Behaviors about the Novel Radical Polymerization Initiated with Some Kind of Ionic Liquid | BOOK OF ABSTRACTS the 18th IUPAC International Symposium on Organometallic Chemistry Directed Towards Organic Synthesis, (2015) 369-370.／(Hotel Meliá Sitges / Barcelona, Spain) | Ionic liquids are compounds composed entirely of ions and are liquid at relatively low temperatures (＜100 ℃). Many kinds of ionic liquids containing a variety of cations and anions of different sizes have been synthesized to provide specific characteristics. Meanwhile, the author has shown for the first time that some kinds of ionic liquids can be used to an initiator of radical polymerization. In this investigation, the author would like to present some of the author’s latest research results about the radical initiating ability of ionic liquids. For instance, the author has used the imidazolium ionic liquid such as 1-ethyl-2,3-dimethylimidazolium bromide ([edmim]Br) as an initiator of methyl methacrylate (MMA)-polymerization. The effect of solvents on the polymerization of MMA initiated with [edmim]Br under air at 60 ℃ were examined. As a result, the polymerizations in dimethyl sulfoxide, carbon tetrachloride, and toluene were perfectly inhibited. In contrast to the fact, the polymerization in N,N-dimethylformamide proceeded smoothly. The polymerization behavior as described above was completely different from that of conventional radical polymerization. For this reason, the polymerization initiated with ionic liquid was investigated in detail. |
| Recent Achievements about the Novel Radical Polymerization Initiated with Some Kinds of Organoboron Compounds | BOOK OF ABSTRACTS the 18th IUPAC International Symposium on Organometallic Chemistry Directed Towards Organic Synthesis, (2015) 96-97.／(Hotel Meliá Sitges / Barcelona, Spain) | The author has been continuing the research about many kinds of organoboron compounds as an initiator of radical polymerization, and the unique characteristic of these compounds can be understood by the author’s few typical articles. On the other hand, Muraki’s group used diethylmethoxyborane (DEMB) as a simple and effective initiator of living radical polymerization. This article describes the author’s recent studies on the development of novel radical polymerization initiated with some kinds of organoboron compounds. For example, the methyl methacrylate (MMA)-polymerization initiated with DEMB in tetrahydrofuran under air at 60 ℃ proceeded promptly. Noteworthy, the strong inhibition effects of 2,6-di-tert-butyl-p-cresol as a radical inhibitor and 1-dodecanethiol as a radical chain transfer agent suggested that the polymerization proceeds via a radical pathway. |
| Development and Optimization of Organoboron Compounds and Borane-Lewis Base Complexes as an Initiator of Living Radical Polymerization | IME BORON XV Programme and Abstreacts, (2014) 150.／(CTU in Prague Faculty of Mechanical Engineering/ Praha, Czech Republic) | In my laboratory, a wide range of research has been done about the unique radical polymerization using many kinds of organoboron compounds as an initiator to date. On the other hand, to my best knowledge, until now there have been no research concerning the radical polymerization using borane-Lewis base complexes as an initiator except for my investigations. It should be paid attention here is that the radical polymerization using some kinds of organoboron compounds and borane-Lewis base complexes as an initiator exhibits a living nature. On the other hand, the most recent fundamental breakthrough in the practice of living radical polymerization initiated with organoboron compounds was achieved by Muraki et al. , in which they used diethylmethoxyborane (DEMB) as an initiator. That is to say, it was revealed that DEMB as a living radical initiator is a very effective and attractive reagent to improve thermostability of thermoset resins. In this way, interesting results have been provided by the use of organoboron compounds and borane-Lewis base complexes as an initiator of unique radical polymerization until recently. This report describes the recent findings about the unique radical polymerization initiated with some kinds of organoboron compounds and borane-Lewis base complexes in my laboratory. The author believes that the detailed works about the unique radical initiating ability of organoboron compounds and borane-Lewis base complexes have led to remarkable insights into the application field of radical polymerization. |
| Recent Advances in the Unique Radical Polymerization Enabled by the Application of Organoboron Compounds as an Initiator | IME BORON XV Programme and Abstreacts, (2014) 117.／(CTU in Prague Faculty of Mechanical Engineering/ Praha, Czech Republic) | It is important to keep firmly in mind that we do not have the perfect understanding of radical polymerization. Consequently, the continuing research of new methods of radical polymerization is of critical importance to the development of polymer chemistry. In the meantime, the importance of organoboron compounds in organic synthesis has been recognized widely. Simultaneously, the extensive research has been done on the radical polymerization using many kinds of organoboron compounds as an initiator including my investigations. In other words, in the past ten years, much effort and ingenuity have gone into the development of unique radical polymerization initiated with some kinds of organoboron compounds in my laboratory. Noteworthy, there are a number of advantages associated with the radical polymerization initiated with organoboron compounds. For example, it became clear that the polymerization initiated with some kinds of organoboron compounds proceeds under air at mild reaction temperatures. In addition, it shows the living characteristics under an unprecedented simple polymerization conditions. In this study, the author reports the newest advanced experimental results about the unique radical polymerization initiated with some kinds of organoboron compounds which is not examined until now. |
| The Application of Ionic Liquids in Future Radical Polymerization Technology | BOOK OF ABSTRACTS 2nd International Conference on Ionic Liquids in Separation and Purification Technology, (2014) P068.／(The Westin Harbour Castle/ Toronto, Canada) | Until now, ionic liquids are of considerable industrial and academic interest as new materials. In the field of polymer chemistry, the idea that ionic liquids may be used as solvents of radical polymerization has a short history, in which the polymerization rate and the molecular weight of obtained polymer in ionic liquids are bigger than those in organic solvents. On the other hand, in the past ten years, much effort and ingenuity have gone into the development of ionic liquids as an initiator of radical polymerization in the author’s laboratory. Because, the author believes that the detailed works about the radical initiating ability of ionic liquids have led to remarkable insights into the application field of ionic liquids. Accordingly, in this study, the author reports the recent advanced experimental results about the radical polymerization initiated with some kinds of ionic liquids. For instance, the author has used the imidazolium ionic liquid such as 1-ethyl-3-methylimidazolium acetate ([emim]Acetat) as an initiator of butyl acrylate(BA)-polymerization. The effects of initiator concentration on the polymerization of BA initiated with [emim]Acetat under argon at 70 ℃ were examined. As a result, the dependence of the polymerization rate to the initiator concentration was confirmed. This is the direct proof about the initiating ability of [emim]Acetat. |
| Recent Advances in Ionic Liquids in Terms of an Initiator of Unique Radical Polymerization | BOOK OF ABSTRACTS 2nd International Conference on Ionic Liquids in Separation and Purification Technology, (2014) O14.2.／(The Westin Harbour Castle/ Toronto, Canada) | Most scientists understand that ionic liquids are not only fascinating substance but are still unknown substance. Therefore, extensive research has been undertaken to explore the application of ionic liquids. This situation is similar in polymer chemistry fields. However, to the best of the author’s knowledge, in spite of their potential applications in polymer chemistry fields, no studies on the radical initiating ability of ionic liquids have been undertaken except for the author’s investigation. That is to say, until now, it has been proven in the author’s laboratory that there are many examples of ionic liquids which function as initiators of unique radical polymerization. On the other hand, in regard to the radical initiating ability of ionic liquids, it is a fact that the obtained experimental results leave an important question unanswered. From such a background, in order to gain more valuable information about the radical initiating ability of ionic liquids, this presentation outlines the recent development of the author’s knowledge and understanding of the novel radical polymerization using ionic liquids as an initiator. As the one example, the author has focused on 1-ethyl-2,3-dimethylimidazolium bromide ([edmim]Br) as an initiator of radical polymerization. For example, the polymerization of vinyl acetate (VAc) initiated with [edmim]Br under the atmosphere of air at 70 ℃ proceeds only in the limited solvent such as diglyme. On the other hand, this [edmim]Br-initiated polymerization of VAc in diglyme was completely inhibited in the presence of radical inhibitors such as hydroquinone and 2,6-di-tert-butyl-p-cresol. Needless to say, the fact that the thermal self-initiated polymerization of VAc under the same reaction conditions did not proceed. From the data obtained here, it is immediately clear that the [edmim]Br-initiated polymerization of VAc proceeds via a solvent-selected radical pathway. That is to say, this polymerization behavior is completely different from that of conventional radical polymerization. |
| Solvent Influences on the Radical Initiating Ability of Imidazolium Ionic Liquids | BOOK OF ABSTRACTS The 12th International Conference on Frontiers of Polymers and Advanced Materials, (2013) SYN-M113.／(Owen G Glenn Building, University of Auckland / Auckland, New Zealand) | Ionic liquids are low melting point (< 100 ℃) organic salts. Nowadays, they are attractive for many investigations because of their thermal stability, high ionic conductivity, low flammability, negligible vapor pressure, and a large electrochemical window. Historically, the first report of an ionic liquid appeared in 1914. By the mid 1990s, the basic understanding of the ionic liquids concept was well known in a narrow scientific community, mostly electrochemists. However, presently, an increasing attention is paid to the use of ionic liquids in many fields of academia and industry. Correspondingly, a new application of ionic liquids as an initiator for radical polymerization was demonstrated in my laboratory for the first time. The object of this investigation is to explore the possibility for imidazolium ionic liquids as a novel initiator of radical polymerization. Especially, solvent effects on the radical polymerization initiated with imidazolium ionic liquids were investigated in detail. For instance, I have used the imidazolium ionic liquid such as 1-ethyl-2,3-dimethylimidazolium bromide ([edmim]Br) as an initiator of methyl acrylate (MA)-polymerization. The polymerization of MA initiated with [edmim]Br in N,N-dimethylformamide (DMF) proceeded smoothly under air at 80 ℃. Additionally, this MA-polymerization was completely inhibited in the presence of radical inhibitors such as hydroquinone and 2,6-di-tert-butyl-p-cresol. Likewise, the radical chain transfer agent such as 1-dodecanethiol perfectly inhibited the polymerization. On the other hand, in regard to the dependence of MA conversion under air at 80 ℃ in different solvents on the polymerization time. it can be seen that the polymerization did not proceed in a no polar solvent such as toluene. Furthermore, surprisingly, although the reaction proceeded in a highly polar solvent such as DMF, the reaction did not proceed at all in a similar highly polar solvent such as dimethylsulfoxide. From the data obtained here, it is immediately clear that the [edmim]Br-initiated polymerization of MA proceeds via a solvent-selected radical pathway that is entirely different from conventional radical polymerization. |
| Challenges for New Application of Ionic Liquids for an Unique Initiator of Radical Polymerization |
BOOK OF ABSTRACTS The 12th International Conference on Frontiers of Polymers and Advanced Materials, (2013) SYN-O-13.／(Owen G Glenn Building, University of Auckland / Auckland, New Zealand) | It is well known that the establishment of radical polymerization in the mid-twentieth century spurred interest in understanding the underlying application of polymer material. On the other hand, the scope of ionic liquids for research has expanded rapidly over the last twenty years. Against this backdrop, I have confirmed the effectiveness of ionic liquids as an initiator for radical polymerization up to now for the first time. This investigation covers recent achievements in the field of unique radical polymerization initiated with ionic liquids. As one example, I have focused on S-ethyl-N,N,N‘,N‘-tetramethylisothiouronium trifluoromethanesulfonate ([etmi]otf) as an initiator of radical polymerization. The effects of solvents on the polymerization of butyl acrylate (BA) initiated with [etmi]otf under argon at 70 ℃ or 60 ℃ were examined. From the results, it can be seen that the polymerization can be promoted strongly in the limited kinds of solvents such as dioxane and tetrahydrofuran. On the other hand, I have shown that there are a few additional characteristic points in this BA-polymerization initiated with [etmi]otf. That is to say, the BA-polymerization proceeded also in diglyme under the same reaction conditions as described above. Additionally, the presence of a radical inhihibitor such as hydroquinone decreased the rate of the BA-polymerization, and an addition of a radical chain transfer agent such as 1-dodecanethiol strongly depressed the molecular weight of obtained polymer. Most basically, these experimental results provided a clear evidence for [etmi]otf as an unique initiator of radical polymerization. |
| Unique Properties of Ionic Liquids as an Initiator of Radical Polymerization | Baltic Polymer Symposium 2013 PROGRAMME AND ABSTRACTS, (2013) 86.／(Trasalis Resort ＆ SPA / Trakai, Lithuania) | I have shown for the first time that imidazolium ionic liquid such as 1-ethyl-2,3-dimethylimidazolium bromide ([edmim]Br) has the ability to initiate the radical polymerization. The polymerization of methyl methacrylate (MMA) initiated with [edmim]Br in N,N-dimethylformamide (DMF) proceeded smoothly under air at 80 ℃.However, the corresponding polymerization under argon scarcely proceeded. On the other hand, The polymerization was perfectly inhibited in the presence of hydroquinone and 2,6-di-tert-butyl-p-cresol as radical inhibitors and 1-dodecanethiol as a radical chain transfer agent. From the data obtained here, it is immediately clear that the [edmim]Br-initiated polymerization of MMA proceeds via a radical pathway that is different from that of conventional radical polymerization. |
| Organoborane Wonderland: from the Viewpoint of an Initiator of Radical Polymerization | Baltic Polymer Symposium 2013 PROGRAMME AND ABSTRACTS, (2013) 36.／(Trasalis Resort ＆ SPA / Trakai, Lithuania) | In this study, I have reported the recent achievement of the unique radical polymerization systems of various vinyl monomers initiated with alkylborane and borane complex. The most remarkable feature of these alkylborane- and borane complex-initiated polymerizations is the fact that these polymerization reactions proceed under air at mild reaction temperature ranges, e.g., 0 ℃ – 70 ℃. Furthermore, the molecular weight of the obtained polymer increases with monomer conversion in some of these polymerizations, suggesting the living properties of these polymerizations. Consequently, compared with other living radical polymerization systems reported, these novel living radical polymerization systems have the possibility to offer a more general and efficient way toward the industrial production of various tailor-made polymers.1)-3) For example, I have established a new facile living radical polymerization initiated with 9-BBN until now, in which the polymerization proceeds easily under air at mild reaction temperatures. This novel living radical polymerization process was named “hydroboration-autoxidation living radical polymerization”. The mechanism of the polymerization can be briefly explained as follows. Vinyl monomer-9-BBN adduct is formed via hydroboration reaction, and the oxidation reaction rapidly takes place at the C-B bond of the vinyl monomer-9-BBN adduct to form boron peroxide (C-O-O-B) which can homolytically cleavage to generate an alkoxy radical (C-O・) and a borinate radical (B-O・). After the homolytical cleavage of the boron peroxide, the alkoxy radical initiates the polymerization and the borinate radical forms the dormant species of the propagating chain end. |
| The Role of Solvents in the Unique Radical Polymerization Initiated with Some Kinds of Ionic Liquids | BOOK OF ABSTRACTS MACRO2012 IUPAC World Polymer Congress, (2012) 142169-W091.／(Virginia Tech / Blacksburg, U.S.A.) | Nowadays, radical polymerization is a very important commercial process for preparing high molecular weight polymers because it can be employed for polymerization of many vinyl monomers under relatively mild reaction conditions. In the mean time, it is now generally accepted that the nature of the initiator not only influences the rate of polymerization and the molecular weight of the polymer formed but also affects the polymer structure and thereby possibility polymer properties as well. For this reason, it has been realized that the research and development of new class of radical initiators contributes further development in the field of radical polymerization. In other words, the new class of radical initiators are of academic and commercial importance. On the other hand, ionic liquids have emerged as an exceptionally valuable reagents among many sections of the chemistry community for their potential. Therefore, many scientists have been studying these interesting materials with respect to their properties and application, in the last twenty years. However, there has been no research on the radical polymerization initiated with ionic liquids except for my researches. The present investigation is an extension of the work to dissolve the exact mechanism of the polymerization initiated with ionic liquid. For example, the polymerizations of n-butylacrylate (BA) initiated with 1-ethyl-3-methylimidazolium acetate ([emim]Acetat) under air and under argon at 70 ℃ or 60 ℃ in bulk or in some kinds of organic solvents were carried out. From these data, it has been clearly shown that the polymerizations under air were completely inhibited, but the polymerizations under argon proceeded in limited solvents. In particular, a striking feature of the BA-polymerization initiated with [emim]Acetat under argon in toluene is the molecular weight distribution of obtained polymer is narrow instead of its relatively high molecular weight. On the other hand, the BA-polymerization in toluene under argon was perfectly inhibited in the presence of hydroquinone as a radical inhibitor. From the data obtained here, it is immediately clear that the polymerization proceeds via a solvent-enhanced radical pathway. In other words, the reaction behavior of the BA-polymerization initiated with [emim]Acetat is completely different from that of traditional radical polymerization. Much research efforts on the radical initiating ability of ionic liquids are under way in my laboratory. |
| The Potential of Ionic Liquids as a Novel Initiator of Radical Polymerization | BOOK OF ABSTRACTS MACRO2012 IUPAC World Polymer Congress,(2012) 142160-W128.／(Virginia Tech / Blacksburg, U.S.A.) | Ionic liquids has continued to attract the attention of both academics and industrialists because they have intrinsically valuable properties, such as thermal stability, high ionic conductivity, large electrochemical window, low vapour pressure and ease of recycling that facilitate product recovery and may reduce environmental emissions. Viewed from a different angle, since ionic liquids are characterized by good thermal and chemical stability, nobody focuses on them as an initiator of radical polymerization. However, I have been targeting ionic liquids as an specific initiator of radical polymerization. Until now, their potential in the initiating ability of radical polymerization has been recognized, but detailed applications have not been explored yet. Accordingly, in this study, I report the recent interested experimental results about radical polymerization initiated with some kinds of ionic liquids. For instance, the results of the polymerization of butyl acrylate (BA) initiated with isouronium-based ionic liquid such as O-ethyl-N,N,N’,N’-tetramethylisouronium trifluoromethanesulfonate ([etmi]otf) in bulk and in various solvents under air at 60 or 70 ℃ were carried out. Noteworthily, it can be understood from the data that the polymerization in toluene proceeds smoothly, but the polymerization in bulk and in other solvents completely inhibited. Needless to say, the thermal polymerization of BA under the same reaction conditions is perfectly inhibited. The fact indicates that [etmi]otf itself initiates the polymerization. On the other hand, the BA-polymerization under air in diglyme also proceeded smoothly, and the addition of the radical chain transfer agent such as 1-dodecanethiol reduced the molecular weight of obtained polymer. The results obtained here suggests that [etmi]otf-initiated polymerization proceeds via a radical pathway, but the polymerization behavior is different from that of conventional radical polymerization. A final point that should be mentioned is that the experimental results obtained here will contribute to the many research fields of ionic liquids. |
| The Use of Ionic Liquids in Solvent-enhanced Radical Polymerization | BOOK OF ABSTRACTS Eurasia-12, (2012) S14-PP10.／ (the Chandris Hotel / the Island of Corfu, Greece) | Needless to say, although radical polymerization processes are some of the oldest in the history of synthetic polymers, there are still fundamental issues that are not well understood. In the mean time, the academic and industrial interest in ionic liquid technologies has increased significantly over the past decade, whereas unfortunately ionic liquids are still unfamiliar to some scientists. In this investigation, the author has studied the initiating ability of radical polymerization about some kinds of ionic liquids. A striking feature of the polymerization initiated with some kinds of ionic liquids is that the initiating activity strongly depends on solvent. To put it concretely, the polymerizations of vinyl acetate initiated with 1-ethyl-3-methylimidazolium thiocyanate under air in bulk or in some kinds of organic solvents were carried out. The polymerization proceeded in limited solvents, especially in tetrahydrofuran. Furthermore, it can be seen that the vinyl acetate-polymerization under air in tetrahydrofuran at 60℃ was strongly inhibited in the presence of 2,6-di-tert-butyl-p-cresol and hydroquinone as a radical inhibitor and 1-dodecanethiol as a radical chain transfer agent. The result clearly suggests that the polymerization proceeds via a radical pathway. However, it can be noted that the kinetics of the polymerization was completely different from that of traditional radical polymerization. Suffice it to say that the outstanding properties of the polymerization initiated with some kinds of ionic liquids provide not only new utility but also scientific interest. It is not expected that ionic liquids simply cleavage to form radicals that initiate polymerization. As a result, even though there are several complexing factors not allowing highly quantitative descriptions of the initiating radical, the qualitative features of this polymerization are very important for the nature of ionic liquids. |
| Investigation of Ionic Liquid Precursor Properties as an Initiator of Unique Radical Polymerization | BOOK OF ABSTRACTS Eurasia-12, (2012) S14-OP1.／ (the Chandris Hotel / the Island of Corfu, Greece) | Ionic liquids are not new, however, the current developments about science and technology of ionic liquids provide a portfolio of new mind and new approach to scientists and engineers. Since ionic liquids are characterized by good thermal and chemical stability, nobody focuses on them as an initiator of radical polymerization. However, I have been targeting ionic liquids as a specific initiator of radical polymerization. The results obtained there could not have been predicted with current knowledge prior to the experiment. In other words, there is a cotroversial suggestion on the obtained results relating to the radical initiating ability of ionic liquids. Anyhow, until now, their potential in the initiating ability of radical polymerization has been recognized, but detailed applications have not been explored yet. Accordingly, in this context, I report the recent interested experimental results about radical polymerization initiated with some kinds of ionic liquids For example, the polymerizations of n-butylacrylate initiated with S-ethyl-N,N,N’,N’-tetramethylisothiouronium tris(pentafluoroethyl)trifluorophosphate under air and under argon at 70 ℃ or 60 ℃ in bulk or in some kinds of organic solvents were carried out. The polymerizations under air were completely inhibited, but the polymerizations under argon proceeded in limited solvents. In addition, the polymerization in toluene under argon was strongly inhibited in the presence of 2,6-di-tert-butyl-p-cresol and hydroquinone as a radical inhibitor. From these data, it is immediately clear that the polymerization proceeds via a radical pathway. On the other hand, it can be noted that the kinetics of the polymerization in toluene under argon was completely different from that of conventional radical polymerization. |
| Solvent Influences on the Ionic Liquid-initiated Radical Polymerization | BOOK OF ABSTRACTS 1IUPAC 7th International Conference on Novel Materials and their Synthesis (NMS-VII) & 21st International Symposium on Fine Chemistry and Functional Polymers (FCFP-XXI), (2011) P36.／ (Fudan University / Shanghai, China) | Here the author presents recent results for the solvent effect about the radical initiating ability of ionic liquids. As a typical example of the effect of solvent on the polymerization initiated with ionic liquid, the styrene-polymerization initiated with 1-ethyl-2,3-dimethylimidazolium bromide under air and under argon are investigated. Interestingly, the polymerization in diglyme proceeds to some extent, but the polymerizations in bulk and in other solvents scarcely proceed. This phenomenon is completely different from traditional radical polymerization. |
| Development and Optimization of Some Kinds of Ionic Liquids as an Initiator of Unique Radical Polymerization | BOOK OF ABSTRACTS 1IUPAC 7th International Conference on Novel Materials and their Synthesis (NMS-VII) & 21st International Symposium on Fine Chemistry and Functional Polymers (FCFP-XXI), (2011) C39.／ (Fudan University / Shanghai, China) |
In this work, the author reports the recent interested experimental results about radical polymerization initiated with some kinds of ionic liquids. The data about the effect of the chemical structure of ionic liquids as an initiator on the initiating ability of butyl acrylate-polymerization under air in toluene at 60 ℃ are investigated. As ionic liquids, cations such as trihexyl(tetradecyl)phosphonium, 1-octadecyl-3-methylimidazolium ([amim]), 1-ethyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium ([hmim]), 1-butyl-3-methylimidazolium, and N-hexylpyridinium ([hpyr]) are used in combination with anions such as bis(trifluoromethylsulfonyl)imide (TFSI), bis[oxalato(2-)]borate, tris(pentafluoroethyl)trifluorophosphate, tetrafluoroborate, trifluoroacetate, hexafluorophosphate (PF6), and trifluoromethanesulfonate. Only some kinds of ionic liquids such as [amim]TFSI, [hmim]TFSI, [hpyr]TFSI, and [hpyr]PF6 have the initiating ability. It has been currently underway paradigm that the choice of which ionic liquid to use as an initiator can have a dramatic effect on the outcome of the polymerization reaction. |
| Solvent-Assisted Radical Polymerization Initiated with Phosphonium-Based Ionic Liquids | BOOK OF ABSTRACTS 11th International Conference on Frontiers of Polymers and Advanced Materials, (2011) 156.／(Conference Centre University of Pretoria / Pretoria, South Africa) |
The author has been targeting ionic liquids as an specific initiator of radical polymerization so far, while there are no reports about the application of ionic liquids as an initiator of radical polymerization except for the author’s investigations. In order to further understand the nature of the ionic liquid-initiated polymerization, in this communication, the author discusses fundamental features of the vinyl polymerization initiated with phosphonium-based ionic liquids. One can observe the typical example of the polymerization initiated with phosphonium-based ionic liquid such as trihexyl(tetradecyl)phosphonium tetrafluoroborate ([P(h3)t]BF4,) as follows. The MMA- polymerization initiated with [P(h3)t]BF4 under argon in diglyme at 70 ℃ proceeds smoothly, but the polymerization in the presence of 2,6-di-tert-butyl-p-cresol (BHT) as a radical inhibitor or 1-dodecanethiol (1-DT) as a radical chain transfer agent is completely inhibited or scarcely proceeds. The result strongly suggests that [P(h3)t]BF4 has an initiating ability of radical polymerization. The most striking characteristic of the [P(h3)t]BF4-initiated polymerization is that the bulk polymerization is strongly inhibited under otherwise similar polymerization conditions. This polymerization behavior is unique and marked different from that of traditional radical polymerization. Consequently, the MMA-polymerization initiated with [P(h3)t]BF4 can be called “solvent-assisted” radical polymerization. |
| New Aspects of Ionic Liquids as a Novel Initiator of Radical Polymerization | BOOK OF ABSTRACTS 11th International Conference on Frontiers of Polymers and Advanced Materials, (2011) 128.／ (Conference Centre University of Pretoria / Pretoria, South Africa) |
The research about ionic liquids consisting of bulky organic cations paired with various kinds of different anions has grown exponentially and ionic liquids became more familiar to a broad public in recent years. For instance, some kinds of ionic liquids are expected as green solvents for free radical polymerization by virtue of their negligible vapor pressure, nonflammability, temperature stability, and chemical stability. In the mean time, until now, the author reported an radical initiating ability of some kinds of ionic liquids. In the present work, the author discusses the unique radical initiating ability of some kinds of ionic liquids. The typical examples of the polymerization initiated with ionic liquids are as follows. From the data about the effect of a radical chain transfer agent such as 1-dodecanethiol (1-DT) and radical inhibitors such as hydroquinone (HQ) and 2,6-di-tert-butyl-p-cresol (BHT) on the polymerization of methyl acrylate (MA) initiated with 1-butyl-3-methylimidazolium thiocyanate ([bmim]SCN) as an ionic liquid under air in tetrahydrofuran (THF) at 60 ℃, it was clear that the MA-polymerization in the presence of [bmim]SCN proceeded smoothly in contrast to the fact that the purely thermal, self-initiated polymerization of MA is completely inhibited. In addition, the inhibitory effects of 1-DT, HQ, and BHT can be observed clearly. That is to say, it is strongly indicated that [bmim]SCN has initiating ability of radical polymerization. On the other hand, it is widely accepted that the solvent effects in conventional radical polymerization are usually much less significant than for ionic polymerization. Interestingly, it can be seen another data that the MA-polymerization initiated with [bmim]SCN in THF proceeds smoothly, but the polymerization in toluene scarcely proceeds; e.g., 44.7 % and 2.0 % conversions can be observed respectively after 4 hours. The result suggests that the MA-polymerization initiated with [bmim]SCN is apparently influenced by the selection of the solvent. In this manner, the MA-polymerization initiated with [bmim]SCN is different from conventional radical polymerization at this point. |
| Impact Behavior of Phosphonium-Based Ionic Liquids as a Novel Initiator of Radical Polymerization | BOOK OF ABSTRACTS The 11th International Chemistry Conference and Exhibition in Africa, (2010) 337./ Pyramisa Isis Hotel Luxor (Luxor, Egypt). |
The author recognized that there may be no research on the radical polymerization initiated with ionic liquid except for the author’s investidations.In this study, the author discussed fundamental features of the radical polymerization initiated with some phosphonium-based ionic liquids. For example, until then, the author reported an radical initiating ability of trihexyl(tetradecyl)phosphonium tetrafluoroborate ([P(h3)t]BF4), but the initiating mechanism was not clear. Consequently, a further study about the detailed mechanism of [P(h3)t]BF4-initiated polymerization was needed. Needless to say, the kinetic aspects of the radical polymerization process are very important for the better understanding of the polymerization mechanism. As typical examples, from the data for the effect of initiator concentration and monomer concentration on the polymerization of methyl methacrylate (MMA) initiated with [P(h3)t]BF4 under air at 70 oC in dioxane, it was easily understood that the initiator concentration does not affect the rate of polymerization. In addition, surprisingly, the rate of polymerization decreased with increase of the monomer concentration. In the typical case of conventional radical polymerization, the rate of polymerization is proportional to the square root of the initiator concentration, and that is first order with respect to monomer concentration. Consequently, this polymerization seemed to be significantly different from the usual radical polymerization at this point. |
| The Novel Conception of Ionic Liquids as an Initiator of Radical Polymerization of Vinyl Monomers | BOOK OF ABSTRACTS The 11th International Chemistry Conference and Exhibition in Africa, (2010) 265./ Pyramisa Isis Hotel Luxor (Luxor, Egypt). |
The author targeted ionic liquids as an specific initiator of radical polymerization so far, while there were no reports about the application of ionic liquids as an initiator of radical polymerization except for the author’s investigations. Generally, since ionic liquids are characterized by good thermal and chemical stability, nobody focuses on them as an initiator of radical polymerization. Hence, in this study, the author discusses the simple approach to prove the initiating ability of radical polymerization on some kinds of ionic liquids. One can observe the typical example as follows. From the data about the effect of temperature on the polymerization of ethyl acrylate (EA) initiated with 2,2′-azobisisobutyronitrile (AIBN) as a conventional radical initiator and 1-butyl-3- methylimidazolium thiocyanate ([bmim]SCN) as an ionic liquid under air in tetrahydrofuran, it was obviously that the polymerization proceeds via radical pathway, because the inhibitory effects of 1-dodecanethiol as a radical chain transfer agent and hydroquinone or 2,6-di-tert-butyl-p-cresol as a radical inhibitor were observed. One should pay attention to the fact that a 15.6 % conversion of EA was observed in [bmim]SCN-initiated polymerization at 40 oC after 120 minutes, but AIBN did not initiate the EA-polymerization under the same reaction conditions. Needless to say, thermal polymerization of EA under same reaction conditions did not proceed. The obtained results indicate that [bmim]SCN has the initiating ability of radical polymerization. Additionally, with regard to the temperature range on the initiating activity the results show an advantage of [bmim]SCN, which is more wide than that of AIBN. |
| Recent Achievements in Radical Polymerization of Vinyl Monomers Initiated with Ionic Liquids | Macro2010 – 43rd IUPAC World Polymer Congress Polymer Science in the Service of Society – Abstract book and programme, (2010) C11＿O23. / Scottish Exhibition and Conference Centre / (Glasgow, UK). |
In recent years, ionic liquids have been extensively investigated for use as replacement solvents for a variety of radical polymerizations. It is found from some of these investigations that the large increases in both the polymerization rate and the molecular weight of the resulting polymer compared to polymerizations in conventional organic solvents are observed. In addition, to date it is well known that ionic liquids have great potential as media for radical polymerizations because of their outstanding solution properties, vanishing vapor pressure, high thermal stability, and recycling capability. In this manner, in the polymer chemistry community, research and development relating to ionic liquids concentrated mainly on the use of replacement media for radical polymerizations. Nevertheless, the author targeted for the first time ionic liquids as an specific initiator of radical polymerization. In this investigation, the author discusses recent achievements in radical polymerization of vinyl monomers initiated with ionic liquids. For instance, the data about the solution polymerization of butyl acrylate (BA) initiated with 1-ethyl-2,3-dimethylimidazolium bromide ([edmim]Br) in diglyme under air at 70 oC suggest that the polymerization proceeds via a radical pathway, because the inhibitory effects of hydroquinone or 2,6-di-tert-butyl-p-cresol as a radical inhibitor and 1-dodecanethiol as a radical chain transfer agent were observed. In addition, as contrasted with the polymerization at 70 ℃, the polymerization at 60 ℃ under the same reaction conditions was perfectly inhibited. These results about the effects of additives and temperature suggest that [edmim]Br is a thermally decomposing radical initiator. On the other hand, the bulk polymerization and the solution polymerizations in the other conventional organic solvents under air at 70 oC were perfectly inhibited. The solvent effect of the BA-polymerization initiated with [edmim]Br is completely different from that of traditional radical polymerization. Anyhow, the author believes that the author’s investidations in the radical polymerization initiated with ionic liquids have significantly improved the general understanding of ionic liquids. |
| The New Type Radical Polymerization Initiated with Imidazolium Ionic Liquids | BOOK OF ABSTRACTS EUCHEM 2010 Conference on Molten Salts and Ionic Liquids, (2010) 105./ Konzert- und Kongresshalle Bamberg (Bamberg, Germany). |
Although ionic liquids may be the most versatile material among the recently developed materials, the author recognizes that there may be no research on the radical polymerization initiated with ionic liquid except for the author’s investidations. In other words, the author targeted ionic liquids as a specific initiator of radical polymerization for the first time. Without doubt, an answer to the essential question relating to the apparent effectiveness of ionic liquids as a radical initiator is clearly important to systematically understand and evaluate the performance of individual ionic liquids and design new type ionic liquids. In this study, the author discusses fundamental features of the polymerizations initiated with imidazolium ionic liquids. For instance, the data about the effect of temperature on the polymerization of ethyl acrylate initiated with 2,2′-azobisisobutyronitrile (AIBN) as a conventional radical initiator and 1-ethyl-3-methylimidazolium thiocyanate ([emim]SCN) as an ionic liquid under air were tried. This polymerization run can be done in two ways. In one way, the polymerization is initiated with AIBN. Needless to say, all AIBN molecules undergo homolytic bond breakage in a short time at the suitable temperature to produce the initiating radical moiety. In the other way, [emim]SCN initiates the polymerization. In addition, it was clear that the polymerization proceeds via radical mechanism, because the inhibitory effects of 1-dodecanethiol (1-DT) as a radical chain transfer agent and hydroquinone (HQ) or 2,6-di-tert-butyl-p-cresol (BHT) as a radical inhibitor were observed. With regard to the relationship about the initiating ability between AIBN and [emim]SCN, the temperature range on the initiating activity of [emim]SCN is more wide than that of AIBN. For example, only a 15.7 % conversion of EA was observed in AIBN-initiated polymerization at 50 oC after 120 minutes, but a 45.8 % conversion of EA was observed in [emim]SCN-initiated polymerization under same reaction conditions. Moreover, as contrasted with the polymerization at 50 50 oC, only a 22.9 % conversion of EA was observed in [emim]SCN-initiated polymerization at 40 50 oC after 120 minutes, but AIBN did not initiate the EA-polymerization under same reaction conditions. Such experimental results strongly indicate that [emim]SCN has the initiating ability of radical polymerization. In this manner, there is an ongoing investigation in the author’s laboratory to develop the new type radical polymerization initiated with imidazolium ionic liquids. Much of the driving force for the investigation derives from the belief that the determination of the active ionic liquid structure as the initiator of radical polymerization will offer substantial advantages to understand and exploit ionic liquids. Conversely, without improved understanding of ionic liquids as an initiator of radical polymerization, the real comprehension of ionic liquids will be limited. |
| New Possibility of Ionic Liquids as a Novel Initiator of Radical Polymerization | BOOK OF ABSTRACTS 10th INTERNATIONAL CONFERENCE ON FRONTTIERS OF POLYMERS AND ADVANCED MATERIALS, (2009) 89./ Santiago University and Chile University (Santiago de Chile). |
The author has recently reported the property of one or another ionic liquid as a novel initiator of radical polymerization. In this investigation, the author studied the radical polymerization initiated with some kinds of ionic liquids. For example, it has been shown for the first time that 1-ethyl-2,3-dimethylimidazolium bromide ([edmim]Br) exhibited the initiating ability of radical polymerization. The polymerization of methyl methacrylate (MMA) initiated with [edmim]Br proceeded under air at 70 oC in N,N- dimethylformamide, however, an addition of radical inhihibitors such as hydroquinone or 2,6-di-tert-butyl-p-cresol completely inhibited the polymerization. In addition, the rate of the MMA-polymerization in the presence of radical chain transfer agent such as 1-dodecanethiol was strongly depressed, and the molecular weight of obtained polymer was reduced. Needless to say, thermal polymerization of MMA under same reaction conditions did not proceed. In the meanwhile, the polymerization behavior of ethyl acrylate initiated with [edmim]Br under argon at 70 oC in toluene was almost same as that of MMA initiated with [edmim]Br as described above. |
| Application of Guanidinium Ionic Liquids as a Specific Initiator of Radical Polymerization | Preprints of EUCHEM 2008 Conference on Molten Salts and Ionic Liquids, (2008) 148. ／Admiral Hotel (Copenhagen, Denmark) | The author initially recognized the suitability of ionic liquids as an initiator for radical polymerization. In order to find the new possibility of ionic liquids as an initiator for radical polymerization, in this study, the author studied the vinyl polymerization initiated with guanidinium-based ionic liquids. The kinetic order of the guanidinium tris(pentafluoroethyl)trifluorophosphate-initiated polymerization of styrene(St) in bulk was completely different from that of conventional radical polymerization. Moreover, the remarkable feature of the St-polymerization is that the molecular weights of obtained polymers are very mall in spite of their relatively high percentages of conversion. |
| Monomer Selective Radical Polymerization Initiated with 1-Hexyl-3-methylimidazolium Bromide |
Preprints of 3rd International Conference on Green and Sustainable Chemistry, (2007) 104./ Department of Biotechnology of the Delft University of Technology (Delft, The Netherlands). | Until then the author reported the application of ionic liquids as an initiator of vinyl polymerization. The object of this investigation is to explore the possibility for imidazolium ionic liquids as a novel initiator of vinyl polymerization. The author has shown for the first time that imidazolium ionic liquid such as 1-hexyl-3-methylimidazolium bromide ([hmim]Br) has the ability to initiate the radical polymerization. For example, the polymerizations of styrene and methyl methacrylate (MMA) initiated with [hmim]Br under air and argon at 70 ℃ in bulk were completely inhibited or scarcely proceeded. Furthermore, these polymerizations in benzene, toluene, carbon tetrachloride and dimethyl sulfoxide exhibited the same tendency. However, it was proved that the MMA polymerization initiated with [hmim]Br in tetrahydrofuran at 60 ℃ under air and under argon proceeded smoothly via a radical pathway as a result of careful consideration. Alternatively the careful consideration indicated strongly that [hmim]Br possesses the ability to initiate the radical polymerization of a limited number of vinyl monomers in a limited number of solvents. After all, the author believes that [hmim]Br is very attractive for the novel initiator of unique radical polymerization, because [hmim]Br selectively initiates a limited number of vinyl monomers. |
| Vinyl Polymerizations Initiated with Ionic Liquids | Preprints of the 2005 International Chemical Congress of Pacific Basin Societies, (2005) Program Number:127. / Mid Pacific Conference Center and Waikiki Beach Marriot (Honolulu, Hawaii, U.S.A.). |
This research concerns the novel radical polymerization of vinyl monomer initiated with ioinic liquids (ILs). ILs have been found to be nonvolatile and recyclable reaction media for a wide range of chemical reactions. Their use leads to significant improvements in rate and yield in many organic reactions. In addition, the large increases in both the rate and the molecular weights are observed in some kinds of radical polymerizations when ILs are used in place of conventional organic solvents. I have used the ioinic liquid, trihexyl(tetradecyl) phosphonium bis(trifluoromethylsulfonyl)imide, [P(h3)t]TFSI, as a neoteric initiator for the radical polymerizations of styrene (St). The polymerization of St initiated with [P(h3)t]TFSI at 60 ℃ in tetrahydrofuran proceeded smoothly under argon and under air, whereas the polymerization was stopped in the presence of 2,6-di-tert-butyl-p-cresol and hydroquinone. Furthermore, an addition of 1-dodecanethiol suppressed the molecular weight of the resulting polymer. The obtained results indicated that the polymerization proceeds via a radical pathway. On the other hand, the molecular weight of the resulting polymer obtained in dioxane under argon increased with the monomer conversion, indicating the possibility of a new controlled radical polymerization mechanism. For better understanding the mechanism of polymerization, the polymerizations of methyl methacrylate, methyl acrylate, ethyl acrylate, and butyl acrylate initiated with [P(h3)t]TFSI were also attempted. |
| Possibility of Borane Complexes and Alkylboranes as an Initiator of Novel Radical Polymerization under Air at Mild Reaction Temperatures | Preprints of the 2005 International Chemical Congress of Pacific Basin Societies, (2005) Program Number:126.／Mid Pacific Conference Center and Waikiki Beach Marriot (Honolulu, Hawaii, U.S.A.). |
A series of polymerizations of vinyl monomers initiated with alkylboranes and borane complexes, e.g. 9-borabicyclo[3.3.1]nonane (9-BBN), (R)- and (S)-B-isopinocampheyl-9-borabicyclo[3.3.1]nonane, borane-tetrahydrofuran complex, borane-methyl sulfide complex, etc., was carried out in order to develop the novel radical polymerization which proceeds under air at mild reaction temperature. For example, the polymerization of styrene (St) initiated with 9-BBN proceeded smoothly under air at 60 ℃. 2,6-Di-tert-butyl-p-cresol as an inhibitor of radical reaction exhibited an inhibitory effect on the polymerization. Furthermore, an addition of 1-dodecanethiol as a radical chain transfer agent suppressed the molecular weights of the resulting polymer. Moreover, the molecular weight of the resulting polymer increases with monomer conversion, indicating that the polymerization has living nature. On the other hand, the polymerization reaction was strictly inhibited under argon. The experimental results were indicative of a new type of living polymerization which proceeds via a specific radical pathway correlated with the oxygen in air. A number of characteristics of the St-polymerization initiated with other alkylboranes and borane complexes exhibited in a similar manner as above. The polymerizations of methyl methacrylate, methyl acrylate, ethyl acrylate, etc, were also investigated in order to shed light on the mechanism of polymerization. |
| Properties of Trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide as an Initiator of Vinyl Polymerization | Preprints of the 8th SPSJ International Polymer Conference, (2005) 493.／Fukuoka International Congress Center (Fukuoka, Japan). | Conventional free radical polymerization and controlled radical polymerization in room temperature ioinic liquids (RTILs) have been reported to date. However, there are no reports of the application of RTILs as an initiator of vinyl polymerization. I have used the RTIL, trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide, [P(h3)t]TFSI, as a neoteric initiator for the polymerization of vinyl monomers such as methyl methacrylate, styrene (St) and acrylic esters. In a typical example, the polymerization of St initiated with [P(h3)t]TFSI at 70 ℃ in dioxane proceeded smoothly under air and argon. 2,6-Di-tert-butyl-p-cresol and hydroquinone had inhibitory effect on the polymerization. Furthermore, an addition of 1-dodecanethiol suppressed the molecular weight of the resulting polymer. These experimental results indicated that the polymerizations proceed via a novel radical pathway. |
| Novel Radical Polymerization Initiated with Alkylboranes and Borane Complexes under Air at Mild Reaction Temperatures | Preprints of the 8th SPSJ International Polymer Conference, (2005) 492.／Fukuoka International Congress Center (Fukuoka, Japan). | A series of polymerizations of vinyl monomers initiated with alkylboranes and boranecomplexes, e.g. 9-borabicyclo[3.3.1]nonane (9-BBN), (R)- and (S)-B-isopinocampheyl-9-borabicyclo[3.3.1]nonane, borane-tetrahydrofuran complex, borane-methyl sulfide complex, etc., was carried out in order to develop the novel radical polymerization which proceeds under air at mild reaction temperatures. For example, the polymerization of styrene initiated with 9-BBN proceeded smoothly under air at 60 ℃. However, the polymerization reaction was strictly inhibited under argon. 2,6-Di-tert-butyl-p-cresol as an inhibitor of radical reaction exhibited an inhibitory effect on the polymerization under air. Furthermore, an addition of 1-dodecanethiol as a radical chain transfer agent suppressed the molecular weights of the resulting polymer. On the other hand, the molecular weight of the resulting polymer increases with monomer conversion, indicating that the polymerization has living nature. The experimental results were indicative of a new type of living polymerization which proceeds via a specific radical pathway correlated with the oxygen in air. |
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