Ogled vira Butanojska kislina

{{Chembox
| Watchedfields = changed
| verifiedrevid = 476997169
| ImageFileL1 = Butyric acid acsv.svg
| ImageSizeL1 = 100px
| ImageNameL1 = Skeletal structure of butyric acid
| ImageFileR1 = Butyric_acid_flat_structure.png
| ImageSizeR1 = 100px
| ImageNameR1 = Flat structure of butyric acid
| ImageFile2 = Butyric-acid-3D-balls.png
| ImageSize2 = 
| ImageName2 = Space filling model of butyric acid
| IUPACName = butanojska kislina
| OtherNames = propankarboksilna kislina
|Section1={{Chembox Identifiers
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 40UIR9Q29H
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| ChEMBL = 14227
| KEGG_Ref = {{keggcite|correct|kegg}}
| KEGG = C00246
| InChI = 1/C4H8O2/c1-2-3-4(5)6/h2-3H2,1H3,(H,5,6)
| InChIKey = FERIUCNNQQJTOY-UHFFFAOYAP
| SMILES1 = CCCC(=O)O
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C4H8O2/c1-2-3-4(5)6/h2-3H2,1H3,(H,5,6)
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = FERIUCNNQQJTOY-UHFFFAOYSA-N
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 107-92-6
| PubChem = 264
| UNNumber = 2820
| EINECS = 203-532-3
| RTECS = ES5425000
| IUPHAR_ligand = 1059
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 259
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 30772
| DrugBank_Ref = {{drugbankcite|correct|drugbank}}
| DrugBank = DB03568
| SMILES = O=C(O)CCC
| MeSHName = Butyric+acid
 }}
|Section2={{Chembox Properties
| C=4 | H=8 | O=2 
| Appearance = brezbarvna tekočina
| Odor = neprijeten
| Density = 1,135 g/cm<sup>3</sup><br> (−43 °C)<ref name=Strieter>F.J.  Strieter, D.H. Templeton  (1962). ''Crystal structure of butyric acid''. Acta Crystallographica '''15''' (12): 1240. doi: 10.1107/S0365110X6200328X. </ref><br> 0,9528 g/cm<sup>3</sup><br> (25 °C)<ref name=Lide>D.R. Lide, urednik (2009). ''CRC Handbook of Chemistry and Physics''. 90. Izdaja.  Boca Raton, Florida: CRC Press. ISBN 978-1-4200-9084-0.</ref>
| MeltingPtC = −5,1
| Melting_ref = <ref name=Lide/>
| BoilingPtC = 163,75
| Boiling_ref = <ref name=Lide/>
| SublimationConditions = pri −35&nbsp;°C [[Sublimacija|sublimira]]<br> Δ<sub>subl</sub>''H''<sup><s>o</s></sup> = 76 kJ/mol<ref name=Lindstrom>P.J. Lindstrom, W.G. Mallard, urednika. ''Butanoic acid''.  NIST Chemistry WebBook. NIST Standard Reference Database Number 69. National Institute of Standards and Technology, Gaithersburg MD. Pridobljeno 13. Junija 2014.</ref>
| Solubility = z vodo se meša v vseh razmerjih
| SolubleOther = rahlo topna v [[Ogljikov tetraklorid|ogljikovem tetrakloridu]],<ref  name=PCh>[http://pubchem.ncbi.nlm.nih.gov/compound/264?from=summary ''Butyric acid'']. PubChem.</ref><br> meša se z [[etanol]]om in [[Eter|etrom]]
| pKa = 4,82<ref  name=PCh/>
| RefractIndex = 1,398 (20 °C)<ref name=Lide/>
| Viscosity = 1,814 c[[Poise|P]] (15 °C)<ref name=BA>[http://chemister.ru/Database/properties-en.php?dbid=1&id=1985 ''Butanoic acid''] {{Webarchive|url=https://web.archive.org/web/20160509102029/http://chemister.ru/Database/properties-en.php?dbid=1&id=1985 |date=2016-05-09 }}.</ref> <br> 0,1426 cP (25 °C)<ref  name=PCh/>
| VaporPressure = 0,112 kPa (20 °C)<ref name=ALS>[http://www.caslab.com/Butanoic-Acid.php5 ''Butanoic Acid'']. ALS Environmental. Pridobljeno 13. junija 2014.</ref>  <br> 0,74 kPa (50 °C)<br> 9,62 kPa (100 °C)<ref  name=PCh/>
| LogP = 0,79<ref  name=PCh/>
| HenryConstant = 5,35,10<sup>-4</sup> L·atm/mol<ref  name=PCh/>
| ThermalConductivity = 1,46·10<sup>5</sup> W/m·K
 }}
|Section3={{Chembox Structure
| Dipole = 0,93 D (20 °C)<ref name=BA/>
| CrystalStruct = [[Monoklinski kristalni sistem|monoklinska]] (−43 °C)<ref  name=PCh/> 
| SpaceGroup = C2/m<ref  name=PCh/>
| LattConst_a = 8,01 
| LattConst_b = 6,82 
| LattConst_c = 10,14<ref  name=PCh/>
| LattConst_alpha = 
| LattConst_beta = 111,45
| LattConst_gamma = 
 }}
|Section4={{Chembox Thermochemistry
| HeatCapacity = 178,6 J/mol·K<ref name=Lindstrom/><ref  name=PCh/>
| DeltaHf = −533,9 kJ/mol
| Entropy = 222,2 J/mol·K<ref name=Lindstrom/>
| DeltaHc = 2183,5 kJ/mol<ref name=Lindstrom/>
 }}
|Section7={{Chembox Hazards
| ExternalMSDS = [http://msds.chem.ox.ac.uk/BU/butyric_acid.html External MSDS]| GHSPictograms = {{GHS05}}<ref name="sigma">{{Sigma-Aldrich| id= w222119|name=Butyric acid|accessdate=2014-06-13}}</ref>
| GHSSignalWord = nevarno
| HPhrases = {{H-phrases|314}}<ref name="sigma" />
| PPhrases = {{P-phrases|280|305+351+338|310}}<ref name="sigma" />
| RPhrases = [[R-stavki|R20/21/22]], {{R34}}, [[R-stavki|R36/37/38]] 
| SPhrases = {{S26}}, {{S36}}, {{S45}}
| EUClass = [[Slika:Hazard C.svg|40px]] jedko ('''C''')<br>[[Slika:Hazard X.svg|40px]] zdravju škodljivo ('''Xn''')
| FlashPtC = 71 to 72
| Flash_ref =
| AutoignitionPtC = 440
| Autoignition_ref = 
| ExploLimits = 2,2–13,4%
| NFPA-H = 3
| NFPA-F = 2
| NFPA-R = 0
| LD50 = 2000 mg/kg (oralno, podgana)
 }}
|Section8={{Chembox Related
| OtherAnions = 
| Function = [[Karboksilna kislina|karboksilne kisline]]
| OtherFunctn = [[propanojska kislina]]<br> [[akrilna kislina]]<br> [[jantarna kislina]]<br> [[jabolčna kislina]]<br> [[vinska kislina]]<br> [[krotonska kislina]]<br> [[fumarska kislina]]<br> [[pentanojska kislina]]
| OtherCpds = [[1-butanol]]<br> [[butiraldehid]]<br> [[metil butirat]]
 }}
}}

'''Masléna kislína''' (iz [[Grščina|grškega]] βούτῡρον [butiron] - maslo, [[IUPAC-ime]]: '''butanojska kislina''') je [[karboksilna kislina]] s kemijsko formulo [[ogljik|C]][[vodik|H]]<sub>3</sub>CH<sub>2</sub>CH<sub>2</sub>-[[karboksilna skupina|COOH]]. Nahaja se med drugim v žaltavem [[maslo|maslu]], po čemer je dobila ime. Maslena kislina je tudi v [[parmezan]]u in izbljuvkih in daje značilen telesni vonj. 

Soli in estri maslene kisline se imenujemo butanoati ali butirati.

Maslena kislina ima žarek [[okus]] s sladkastim priokusom in neprijeten [[vonj]]. [[Človek]] lahko zazna koncentracijo 10 ppm, medtem ko lahko nekateri [[sesalci]] zaznajo veliko manjše količine, na primer [[pes]] 10 ppb.

== Kemijske lastnosti ==
Maslena kislina je kratkoverižna maščobna kislina, ki se pojavlja v naravnih [[maščoba]]h in [[olje|oljih]] zlasti v obliki [[ester|estrov]]. [[Triglicerid]]i z masleno kislino predstavljajo okoli 3–4 % masla. Ko maslo postane žaltavo, se maslena kislina zaradi [[hidroliza|hidrolize]] sprosti iz trigliceridov in zaznamo neprijeten vonj. Je šibka kislina z vrednostjo [[pKa]] 4,82 (podobno kot [[ocetna kislina]], pri kateri je pKa 4,76).<ref>{{navedi splet|url=http://www.linkan.se/files/pdf/product_sheets/INVE/adimix_presentation.pdf|title=Adimix Sodium Butanoate information|archiveurl=https://web.archive.org/web/20090326181328/http://www.linkan.se/files/pdf/product_sheets/INVE/adimix_presentation.pdf|archivedate=2009-03-26|accessdate=2008-10-27|url-status=live}}</ref> 
Maslena kislina se v čisti obliki nahaja pri sobnih razmerah v obliki brezbarvne [[kapljevina|kapljevine]], ki se zlahka meša z [[voda|vodo]], [[etanol]]om in [[eter|etrom]]. Od vodne faze jo lahko ločimo z dodatkom [[sol]]i, na primer [[kalcijev klorid|kalcijevega klorida]].

[[Izomerija|Strukturni izomer]] maslene kisline je izomaslena ali 2-metilpropanojska kislina.

== Pridobivanje ==
Industrijsko jo pridobivajo s [[Fermentacija|fermentacijo]] [[sladkor]]ja ali [[škrob]]a ob dodatku pokvarjenega [[sir]]a; dodan [[kalcijev karbonat]] nevtralizira nastale kisline. Fermentacija škroba do maslene kisline pospeši [[bakterija]] ''[[Bacillus subtilis]]''. 

== sklici==
{{sklici|2}}

{{kemijska škrbina}}
[[Kategorija:Karboksilne kisline]]
[[Kategorija:Maščobne kisline]]
{{normativna kontrola}}