دانلود ترجمه مقاله ویژگی های احتراق خودکار مایعات یونی انتخابی – مجله الزویر

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 چکیده
۱ مقدمه
۲ روش تجربی کار
۳ نتایج و بحث ها
۴ نتیجه گیری

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در اين كار، مطالعه تجربي برروي ويژگي هاي قابل اشتعال براي سه مايع يوني انتخاب شده ارائه شد. درجه حرارت احتراق خودكار براي اين سه مايع يوني اندازه گيري شد كه به مقادير ۴۴۱٫۵ و ۴۲۳٫۱ و ۴۵۲٫۱ بوده و كدها T الزامي براي NFPA70‌شامل ,T2 T1 و T2 مي باشد. نتايج حاصل از منحني DSC نشان مي دهد كه بخارات قابل احتراق ممكن است از محصولات واكنش تجزيه به جاي بخارات مايع يوني بوجود بيايد. ان نيز نشان مي دهد كه درجه حرارت با روش برا.رد ليون نزديك به دماي خودكار احتراق مايع يوني براي كاوش در مايعات يوني با توجه به تجزيه گرمازاي ان در كار حاضر است. با اين حال مي توان با اين استدلال گفت كه براي مايعات يوني به طور كلي نياز به ازمايش هاي بيشتر براي بررسي وجود دارد.

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Introduction Ionic liquids, which are organic salts that will melt below 100 к, are composed of organic cations and inorganic anions. Ionic liquids have the characteristics of relatively low volatility, wide liquids temperature range, and nonflammability. Thus, ionic liquids are deemed to be green solvent replacements for the common used volatile organic solvents in part because of aforementioned characteristics [1, 2]. However, recent researches have indicated that ionic liquids are flammable. Fox et al. have pointed significant decomposition of ionic liquids does occur at 100 к or much below this temperature [3]. Smiglak et al. also indicated that a large group of ionic liquids are combustible due to the nature of their positive heat of formation, oxygen content, and decomposition products [4]. In most countries, the degree of flammability hazard of liquid substance are mainly classified by their flash point. However, Fox et al. indicated that although liquids are classified as a flammable liquid or a nonflammable liquid according to their flash point, the flammability hazard of a material should not be defined by a single flammability test [5]. Heat release characteristics of ionic liquids are investigated in their work and they concluded that it would be more appropriate to describe ionic liquids as having low or deduced flammability hazard, rather than identifying as nonflammable materials [5]. The flash point of a combustible substance is usually defined as the temperature, as determined by testing, at which a liquid (or solid) emits sufficient vapour to form a combustible mixture with air [6]. Although the flash points of traditional organic compounds are deemed to be relevant to their vaporization, Liaw et al. have clearly demonstrated that the flash point of ionic liquids is mainly relevant to their decomposition rather than their vaporization [7]. In fact, ionic liquids recently have been classified as a combustible liquid, a class IIIB liquid, by U.S. Occupational Safety and Health Association (OSHA) [5, 8]. Besides flash point and heat release rate, auto-ignition temperature (AIT) is another important characteristic for assessing the flammability hazard of a material. Two common industrial applications of AIT are: (1) determining the required degree of explosion proof for electric equipment operating this combustible liquid; (2) determining the possible consequence associated with leakage of flammable chemicals. For example, article 500.8 of NFPA 70 code provides that “Class I equipment shall not have any exposed surface that operate at a temperature in excess of the ignition temperature of the specific gas or vapour.” [۹]. Auto-ignition is usually regarded as the ignition of a material commonly in air as the result of heat liberation due to an exothermic oxidation reaction in the absence of an external source such as a spark or flame, and the AIT is then defined as the minimum temperature at which autoignition occurs under the specified condition of test [10]. In general, AIT was regarded as the temperature to which a combustible mixture must be raised so that the rate of heat evolved by the exothermic oxidation reactions of the system will just overcome the rate at which heat is lost to the surroundings [11]. Obviously, the ability of a flammable material to spontaneously ignite is an important characteristic for assessing its flammability hazards and such information is indispensable for people who handle, transport, and store such flammable materials. However, although flash points and heat release rates of ionic liquids are explored and discussed recently, the auto-ignition characteristics of ionic liquids are, to authors’ best knowledge, never investigated in the literature. In this study, the auto-ignition characteristics of three ionic liquids, 1-Ethyl-3-methylimidazolium ethylsulfate, 1-Hexyl-3- methylimidazolium bis(trifluoromethylsulfonyl)imide and 1-Decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, are explored. The other parts of this article are organized as follows. The experimental apparatus, materials, and test procedures are briefly discussed in section 2. Experimental results are summarized and discussed in section 3. Finally, this work is concluded in section 4. 2. Experimental section Experimental Apparatus and Test Procedure. Auto-ignition temperature measurements were made on the K47000 auto-ignition apparatus manufactured by the Koehler instrument company.