查看“︁自燃温度”︁的源代码

'''自燃温度'''（{{lang-en|'''autoignition temperature'''}}）或'''自燃点'''（{{lang-en|'''kindling point'''}}）指的是常压下，可燃物在没有外部[[火源]]点燃时發生[[自燃]]的最低温度。在日常生活中所看到的自燃，原因大部分都是自燃點太低所造成。例如[[白磷]]的自燃點僅為34℃，只要稍微加熱便會自燃，故通常保存於水中。

自燃温度这一温度是用于克服该物质发生燃烧的[[活化能]]。当环境中[[氧气]]含量较高时，该化学物质的燃烧温度将降低。通常用自燃温度衡量某种燃料的混合物。液态化学物质的自燃温度采用下述方法测量：将可燃液体放入500毫升烧瓶中，将烧瓶置于恒温炉中，按照ASTM E659进行测量<ref>E659 – 78 (Reapproved 2000)，“Standard Test Method for Autoignition Temperature of Liquid Chemicals,”ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959</ref>。当测量塑料的自燃温度时，可以在较大的压力和100%氧气环境中测量自燃温度。

==自燃方程==
向物質施加熱流<math>q''</math>，使得它由原來溫度<math> T_0 </math>加熱到自燃點<math>T_{ig}</math>所需的時間<math>t</math>為：

<math>t = \left ( \frac{\pi}{4} \right ) \left(k \rho c \right)\left [ \frac{T_{ig}-T_0}{q''} \right] </math> <ref>Principles of Fire Behavior. ISBN 0-8273-7732-0. 1998. </ref> 

* ''k'' = 熱傳導係數（W/(m·K)）
* ''ρ'' = 密度（kg/m³）
* ''c'' = 比熱容量（J/(kg·K)）
* ''q''（W/m²）
* <math> T_0, T_{ig} </math>（℃或K）
 
==某些物质的自燃温度==
各个资料来源中给出的自燃温度差别很大，只能参考使用。影响自燃温度的因素包括氧气的分压、海拔引起的气压变化、湿度、和等待时间。通常来说烃/空气的自燃温度随烃的相对分子质量增加而减少。支化的烃也比直链烃的自燃温度要高。<ref>Zabetakis, M.G.（1965）, Flammability characteristics of combustible gases and vapours, U.S. Department of Mines, Bulletin 627.</ref>

{| class="wikitable sortable"
|-
! 物质 !! data-sort-type="number" | 自燃温度（℃）<ref name="standCond">标准温度和压强下</ref> !! 自燃温度（℉）<ref name="standCond"/> !! 来源或备注
|-
| [[三乙基硼烷]] || {{convert|-20|C|F|disp=table|sortable=on}}
|-
| [[硅烷]] || {{convert|21|C|F|disp=table|sortable=on}} || <small>或者更低</small>
|-
| [[白磷]]|| {{convert|34|C|F|disp=table|sortable=on}} || <small>与有机物接触时，否则会熔化</small>
|-
| [[二硫化碳]] || {{convert|90|C|F|disp=table|sortable=on}}
|-
| [[乙醚]] || {{convert|160|C|F|disp=table|sortable=on}} || <ref>{{cite web|url=http://www.wolframalpha.com/input/?i=diethyl+ether|title=Diethyl Ether - Safety Properties|publisher=Wolfram&#124;Alpha|access-date=2015-03-19|archive-date=2016-02-03|archive-url=https://web.archive.org/web/20160203185306/http://www.wolframalpha.com/input/?i=diethyl+ether}}</ref>
|-
| [[汽油]]  || {{convert|247|-|280|C|F|disp=table|sortable=on}} || <ref name=ETB/>
|-
| [[乙醇]] || {{convert|363|C|F|disp=table|sortable=on}} || <ref name=ETB>{{citation |url=http://www.engineeringtoolbox.com/fuels-ignition-temperatures-d_171.html |title=Fuels and Chemicals - Autoignition Temperatures |publisher=engineeringtoolbox.com |accessdate=2015-03-19 |archive-date=2015-05-04 |archive-url=https://web.archive.org/web/20150504022056/http://www.engineeringtoolbox.com/fuels-ignition-temperatures-d_171.html }}</ref>
|-
| [[柴油]] || {{convert|399|C|F|disp=table|sortable=on}} || <ref name=TCForensics/> <small>或者更低</small>
|-
| [[丁烷]] || {{convert|405|C|F|disp=table|sortable=on}} || <ref>{{cite web|url=http://www.wolframalpha.com/input/?i=butane|title=Butane - Safety Properties|publisher=Wolfram&#124;Alpha|access-date=2015-03-19|archive-date=2016-02-03|archive-url=https://web.archive.org/web/20160203190935/http://www.wolframalpha.com/input/?i=butane}}</ref>
|-
| [[纸]] ||{{convert|218|-|246|C|F|disp=table|sortable=on}} || <ref>{{cite journal |url=http://www.tcforensic.com.au/docs/article10.html |title=Physical Constants for Investigators |author=Tony Cafe |journal=Journal of Australian Fire Investigators |access-date=2015-03-19 |archive-date=2015-01-27 |archive-url=https://web.archive.org/web/20150127145128/http://www.tcforensic.com.au/docs/article10.html }}（Reproduced from "Firepoint" magazine）</ref><ref name=TCForensics/>
|-
| [[皮革]] ||{{convert|200|-|212|C|F|disp=table|sortable=on}} || <ref name=TCForensics>{{cite web|last1=Cafe|first1=Tony|title=PHYSICAL CONSTANTS FOR INVESTIGATORS|url=http://www.tcforensic.com.au/docs/article10.html|website=tcforensic.com.au|publisher=TC Forensic P/L.|accessdate=11 February 2015|archive-date=2015-01-27|archive-url=https://web.archive.org/web/20150127145128/http://www.tcforensic.com.au/docs/article10.html}}</ref><ref name=LeatherInt>{{cite web|title=Flammability and flame retardancy of leather|url=http://www.leathermag.com/features/featureflammability-and-flame-retardancy-of-leather/|website=leathermag.com|publisher=Leather International / Global Trade Media|accessdate=11 February 2015|archive-date=2015-02-11|archive-url=https://web.archive.org/web/20150211180458/http://www.leathermag.com/features/featureflammability-and-flame-retardancy-of-leather/}}</ref>
|-
| [[镁]] || {{convert|473|C|F|disp=table|sortable=on}}
|-
| [[氢气]] || {{convert|536|C|F|disp=table|sortable=on}} || <ref>{{cite web|url=http://www.wolframalpha.com/input/?i=hydrogen&a=*C.hydrogen-_*Chemical-|title=Hydrogen - Safety Properties|publisher=Wolfram&#124;Alpha|access-date=2015-03-19|archive-date=2016-02-03|archive-url=https://web.archive.org/web/20160203182441/http://www.wolframalpha.com/input/?i=hydrogen&a=*C.hydrogen-_*Chemical-}}</ref>
|}

==参见==
*[[自燃]]
*[[闪点]]

==参考链接==
{{reflist|2}}

[[category:化学性质]]
[[Category:火]]
[[Category:阈温]]