Rastvaranje

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Rastvor kuhinjske soli u vodi

Rastvaranje je proces disperegovanja (ravnomernog razređivanja, raspoređivanja) jedne supstance ili više njih u drugoj. Osim kod pravih smeša, uvek je praćeno razmenom energije sa okolinom.[1][2]

Rastvarač je supstanca koja rastvara rastvorak, čime se formira rastvor. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. The quantity of solute that can dissolve in a specific volume of solvent varies with temperature. Common uses for organic solvents are in dry cleaning (e.g. tetrachloroethylene), as paint thinners (e.g. toluene, turpentine), as nail polish removers and glue solvents (acetone, methyl acetate, ethyl acetate), in spot removers (e.g. hexane, petrol ether), in detergents (citrus terpenes) and in perfumes (ethanol). Water is a solvent for polar molecules and the most common solvent used by living things; all the ions and proteins in a cell are dissolved in water within a cell. Solvents find various applications in chemical, pharmaceutical, oil, and gas industries, including in chemical syntheses and purification processes.

Rastvarač[uredi]

Rastvarač, relativan i konvencionalni pojam, naziv za sredinu u kojoj je neka supstanca disperegovana. Idealan rastvor, smeša, bez hemijskog međudejstva sredine i rastvorene supstance ili sa međudejstvom. Može biti čvrst, tečan ili gasovit. Voda je univerzalan rastvarač. Rastvarači kao voda veoma su značajni za život, takođe i u industriji, a naročito važnu ulogu imaju selektivni rastvarači.

Rastvarači u degazaciji[uredi]

Rastvarači u degazaciji su organska jedinjenja s dvojakom namenom - za rastvaranje degazitora u toku njihove pripreme za upotrebu i za rastvaranje samih bojnih otrova, odnosno za dagazaciju fizičkim putem. Kao rastvarači degazatora najčešće se upotrebljavaju dihloretan, tetrahlorugljenik i titrohloretilen, a kao rastvarači bojnih otrova benzin i petroleum.

Rastvor[uredi]

Rastvor (čvrst, tečan ili gasovit) nastaje mešanjem dveju ili više supstanci. Zasićen rastvor za datu temperaturu ima maksimalnu koncetraciju rastvorene supstance. Nezasićen rastvor je rastvor u kome se može rastvoriti još izvesna količina već rastvorene supstance sve dok se ne dobije zasićen prostor. Prezasićen prostor je rastvor u kome je rastvoreno više supstanci nego što odgovara zasićenom rastvoru. Nestabilan je i iz njega se lako izdvaja, u obliku taloga, višak rastvorene supstance.

Rastvorljivost[uredi]

Rastvorljivost neke supstance predstavlja broj grama supstancije koji se rastvara u 100g rastvarača na određenoj temparaturi.

Višekomponentni[uredi]

Rastvarači[uredi]

Ime Kompozicija
Solvent 645 toluene 50%, butyl acetate 18%, ethyl acetate 12%, butanol 10%, ethanol 10%.
Solvent 646 toluene 50%, ethanol 15%, butanol 10%, butyl- or amyl acetate 10%, ethyl cellosolve 8%, acetone 7%[3]
Solvent 647 butyl- or amyl acetate 29.8%, ethyl acetate 21.2%, butanol 7.7%, toluene or pyrobenzene 41.3%[4]
Solvent 648 butyl acetate 50%, ethanol 10%, butanol 20%, toluene 20%[5]
Solvent 649 ethyl cellosolve 30%, butanol 20%, xylene 50%
Solvent 650 ethyl cellosolve 20%, butanol 30%, xylene 50%[6]
Solvent 651 white spirit 90%, butanol 10%
Solvent KR-36 butyl acetate 20%, butanol 80%
Solvent P-4 toluene 62%, acetone 26%, butyl acetate 12%.
Solvent P-10 xylene 85%, acetone 15%.
Solvent P-12 toluene 60%, butyl acetate 30%, xylene 10%.
Solvent P-14 cyclohexanone 50%, toluene 50%.
Solvent P-24 solvent 50%, xylene 35%, acetone 15%.
Solvent P-40 toluene 50%, ethyl cellosolve 30%, acetone 20%.
Solvent P-219 toluene 34%, cyclohexanone 33%, acetone 33%.
Solvent P-3160 butanol 60%, ethanol 40%.
Solvent RCC xylene 90%, butyl acetate 10%.
Solvent RML ethanol 64%, ethylcellosolve 16%, toluene 10%, butanol 10%.
Solvent PML-315 toluene 25%, xylene 25%, butyl acetate 18%, ethyl cellosolve 17%, butanol 15%.
Solvent PC-1 toluene 60%, butyl acetate 30%, xylene 10%.
Solvent PC-2 white spirit 70%, xylene 30%.
Solvent RFG ethanol 75%, butanol 25%.
Solvent RE-1 xylene 50%, acetone 20%, butanol 15%, ethanol 15%.
Solvent RE-2 Solvent 70%, ethanol 20%, acetone 10%.
Solvent RE-3 solvent 50%, ethanol 20%, acetone 20%, ethyl cellosolve 10%.
Solvent RE-4 solvent 50%, acetone 30%, ethanol 20%.
Solvent FK-1 (?) absolute alcohol (99.8%) 95%, ethyl acetate 5%

Razređivači[uredi]

Ime Kompozicija
Thinner RKB-1 butanol 50%, xylene 50%
Thinner RKB-2 butanol 95%, xylene 5%
Thinner RKB-3 xylene 90%, butanol 10%
Thinner M ethanol 65%, butyl acetate 30%, ethyl acetate 5%.
Thinner P-7 cyclohexanone 50%, ethanol 50%.
Thinner R-197 xylene 60%, butyl acetate 20%, ethyl cellosolve 20%.
Thinner of WFD toluene 50%, butyl acetate (or amyl acetate) 18%, butanol 10%, ethanol 10%, ethyl acetate 9%, acetone 3%.

Fizička svojstva[uredi]

Tabela svojstava uobičajenih rastvarača[uredi]

The solvents are grouped into nonpolar, polar aprotic, and polar protic solvents, with each group ordered by increasing polarity. The properties of solvents which exceed those of water are bolded.

Solvent Chemical formula Boiling point[7]
(°C)
Dielectric constant[8] Density
(g/mL)
Dipole moment
(D)

Nonpolar solvents[uredi]

Pentane CH3CH2CH2CH2CH3 36 1.84 0.626 0.00
Cyclopentane Cyclopentane 200.svg
C5H10
40 1.97 0.751 0.00
Hexane CH3CH2CH2CH2CH2CH3 69 1.88 0.655 0.00
Cyclohexane Cyclohexane-2D-skeletal.svg
C6H12
81 2.02 0.779 0.00
Benzene Benzene 200.svg
C6H6
80 2.3 0.879 0.00
Toluene C6H5-CH3 111 2.38 0.867 0.36
1,4-Dioxane 1-4-Dioxane.svg
C4H8O2
101 2.3 1.033 0.45
Chloroform CHCl3 61 4.81 1.498 1.04
Diethyl ether CH3CH2-O-CH2CH3 35 4.3 0.713 1.15
Dichloromethane (DCM) CH2Cl2 40 9.1 1.3266 1.60

Polarni aprotični rastvarači[uredi]

Tetrahydrofuran (THF) Tetrahydrofuran.svg
C4H8O
66 7.5 0.886 1.75
Ethyl acetate Essigsäureethylester.svg
CH3-C(=O)-O-CH2-CH3
77 6.02 0.894 1.78
Acetone Acetone-2D-skeletal.svg
CH3-C(=O)-CH3
56 21 0.786 2.88
Dimethylformamide (DMF) Dimethylformamide.svg
H-C(=O)N(CH3)2
153 38 0.944 3.82
Acetonitrile (MeCN) CH3-C≡N 82 37.5 0.786 3.92
Dimethyl sulfoxide (DMSO) Dimethylsulfoxid.svg
CH3-S(=O)-CH3
189 46.7 1.092 3.96
Nitromethane CH3-NO2 100–103 35.87 1.1371 3.56
Propylene carbonate C4H6O3 240 64.0 1.205 4.9

Polarni protični rastvarači[uredi]

Formic acid Formic acid.svg
H-C(=O)OH
101 58 1.21 1.41
n-Butanol CH3CH2CH2CH2OH 118 18 0.810 1.63
Isopropyl alcohol (IPA) 2-Propanol2.svg
CH3-CH(-OH)-CH3
82 18 0.785 1.66
n-Propanol CH3CH2CH2OH 97 20 0.803 1.68
Ethanol CH3CH2OH 79 24.55 0.789 1.69
Methanol CH3OH 65 33 0.791 1.70
Acetic acid Essigsäure - Acetic acid.svg
CH3-C(=O)OH
118 6.2 1.049 1.74
Water Wasser Strukturformel V1.svg
H-O-H
100 80 1.000 1.85


Vrednosti parametra Hansenove rastvorljivosti[uredi]

The Hansen solubility parameter values[9][10] are based on dispersion bonds (δD), polar bonds (δP) and hydrogen bonds (δH). These contain information about the inter-molecular interactions with other solvents and also with polymers, pigments, nanoparticles, etc. This allows for rational formulations knowing, for example, that there is a good HSP match between a solvent and a polymer. Rational substitutions can also be made for "good" solvents (effective at dissolving the solute) that are "bad" (expensive or hazardous to health or the environment). The following table shows that the intuitions from "non-polar", "polar aprotic" and "polar protic" are put numerically – the "polar" molecules have higher levels of δP and the protic solvents have higher levels of δH. Because numerical values are used, comparisons can be made rationally by comparing numbers. For example, acetonitrile is much more polar than acetone but exhibits slightly less hydrogen bonding.

Rastvarač Chemical formula δD Dispersion δP Polar δH Hydrogen bonding

Nepolarni rastvarači[uredi]

n-Hexane CH3CH2CH2CH2CH2CH3 14.9 0.0 0.0
Benzene C6H6 18.4 0.0 2.0
Toluene C6H5-CH3 18.0 1.4 2.0
Diethyl ether CH3CH2-O-CH2CH3 14.5 2.9 4.6
Chloroform CHCl3 17.8 3.1 5.7
1,4-Dioxane /-CH2-CH2-O-CH2-CH2-O-\ 17.5 1.8 9.0

Polarni aprotični rastvarači[uredi]

Ethyl acetate CH3-C(=O)-O-CH2-CH3 15.8 5.3 7.2
Tetrahydrofuran (THF) /-CH2-CH2-O-CH2-CH2-\ 16.8 5.7 8.0
Dichloromethane CH2Cl2 17.0 7.3 7.1
Acetone CH3-C(=O)-CH3 15.5 10.4 7.0
Acetonitrile (MeCN) CH3-C≡N 15.3 18.0 6.1
Dimethylformamide (DMF) H-C(=O)N(CH3)2 17.4 13.7 11.3
Dimethyl sulfoxide (DMSO) CH3-S(=O)-CH3 18.4 16.4 10.2

Polarni protični rastvarači[uredi]

Acetic acid CH3-C(=O)OH 14.5 8.0 13.5
n-Butanol CH3CH2CH2CH2OH 16.0 5.7 15.8
Isopropanol CH3-CH(-OH)-CH3 15.8 6.1 16.4
n-Propanol CH3CH2CH2OH 16.0 6.8 17.4
Ethanol CH3CH2OH 15.8 8.8 19.4
Methanol CH3OH 14.7 12.3 22.3
Formic acid H-C(=O)OH 14.6 10.0 14.0
Water H-O-H 15.5 16.0 42.3

If, for environmental or other reasons, a solvent or solvent blend is required to replace another of equivalent solvency, the substitution can be made on the basis of the Hansen solubility parameters of each. The values for mixtures are taken as the weighted averages of the values for the neat solvents. This can be calculated by trial-and-error, a spreadsheet of values, or HSP software.[9][10] A 1:1 mixture of toluene and 1,4 dioxane has δD, δP and δH values of 17.8, 1.6 and 5.5, comparable to those of chloroform at 17.8, 3.1 and 5.7 respectively. Because of the health hazards associated with toluene itself, other mixtures of solvents may be found using a full HSP dataset.

Vidi još[uredi]

Reference[uredi]

  1. ^ Peter Atkins; Julio de Paula (2001). Physical Chemistry (7th izd.). W. H. Freeman. ISBN 0716735393. 
  2. ^ Donald A. McQuarrie; John D. Simon (1997). Physical Chemistry: A Molecular Approach (1st izd.). University Science Books. ISBN 0935702997. 
  3. ^ dcpt.ru Solvent 646 Characteristics (ru)
  4. ^ dcpt.ru Solvent 647 Characteristics (ru)
  5. ^ dcpt.ru Solvent 648 Characteristics (ru)
  6. ^ dcpt.ru Solvent 650 Characteristics (ru)
  7. ^ Solvent Properties – Boiling Point Archived 14 jun 2011 at the Wayback Machine. Xydatasource.com. Retrieved on 26 January 2013.
  8. ^ Dielectric Constant Archived 4 jul 2010 at the Wayback Machine. Macro.lsu.edu. Retrieved on 26 January 2013.
  9. 9,0 9,1 Abbott S, Hansen CM (2008). Hansen solubility parameters in practice. Hansen-Solubility. ISBN 978-0-9551220-2-6. 
  10. 10,0 10,1 Hansen CM (januar 2002). Hansen solubility parameters: a user's handbook. CRC press. ISBN 978-0-8493-7248-3. 

Literatura[uredi]

Spoljašnje veze[uredi]