SUMMARY
• Boiling point : 180°C
• Low volatility
• High flash point
• Non flammable
• Good solvent power
• Not miscible with water
• Excellent toxicological profile
• Low photochemical ozone creation potential
• Pleasant odour
HIGHLIGHTS
Butylal is a non flammable solvent with a good solvent power and a pleasant
odour.
Its toxicological profile does not require any labelling. An atmospheric chemistry
study shows it will make a moderate contribution to the formation of tropospheric
ozone if released in the atmosphere.
Butylal shows good potential in cleaning applications.
IDENTIFICATION
Developed formula :
|
CH3 - CH2 - CH2 - CH2
- O - CH2 - O - CH2 - CH2 - CH2
- CH3 |
Molecular formula :
|
C9H20O2 |
Molecular weight :
|
160.26 |
| Classification numbers : |
CAS n° : 2568-90-3
Einecs n° : 219-909-0
NIOSH (RTECS) n° :
|
| Synonyms : |
Dibutoxymethane
Butylformal
Dibutylformal
Formaldehyde dibutylacetal
Formaldehyde-di-n-butyl-acetal
1,1'-[methylenebis(oxy)]dibutane
1,1'-[methylenebis(oxy)]bis-butane
Butane, 1,1'-[methylenebis(oxy)]bis-
Methyleneglycol-dibutylether
1-butoxymethoxy-butane
|
| Chemical family : |
Acetals |
PHYSICAL-CHEMICAL PROPERTIES
| Boiling point (°C) (760 torr) |
180.50 |
| Flash point (°C) |
Closed cup (Pensky-Martens) |
62 |
| Open cup (Cleveland) |
64 |
| Evaporation rate (DIN 53170) compared to Butyl acetate |
5.54 |
| Kinematic viscosity (E-7 m²/s) (25°C) |
10.83 |
| Surface tension (mN/m) (25°C) |
25.20 |
| Vapour pressure (bar) (20°C) (ASTM D 323-modified) |
<0.02 |
| Density (g/m³) (20°C) |
0.83540 |
| Autoignition temp. (°C) (ASTM E 659) |
220 |
| Melting point (°C) |
-58.10 |
| Lower explosion limit LEL20 (g/m³) (% vol) |
42.0(0.63) |
| Lower explosion limit LEL180 (g/m³) (% vol) |
32.0(0.45) |
| Upper explosion limit LEL180 (g/m³) (% vol) |
1570.0(23.6) |
| Bunsen coefficient (solubility of a gas in a
solvent) (20°C) |
of CO2 |
3.0 |
| of N2O |
4.0 |
| Cetane number (motor) (ASTM D613) |
|
>73.7 |
SOLVENT POWER - SOLUBILITY PARAMETERS
The solvent power of a solvent can be evaluated either by the Kauri-butanol
index or by the solubility parameters.
The higher the Kauri-butanol index, the higher the solvent power.
The index measured according to the ASTM D 1133-90 standard with two different
gums supplied by Roeper GmbH (Hamburg, Germany) are as follows :
| |
Kauri gum type |
| 4938 |
4939 |
| Kauri-butanol index of butylal |
62 |
75 |
By comparison, the Kauri-butanol index of methylal (CH
3-O-CH
2-O-CH
3) and dichloromethane
(CH
2Cl
2) are as follows :
| |
Kauri gum type |
| 4938 |
4939 |
| Kauri-butanol index |
|
|
| Methylal (anhydrous grade) |
101 |
164 |
| Dichloromethane |
125 |
115 |
The solubility parameters calculated according to Hoy and van Krevelen are as
follows. They are expressed in (MPa
1/2). A comparison is given with methylal.
| |
 t |
d |
p |
h |
| Butylal |
16.23 |
14.70 |
3.43 |
5.96 |
| Methylal |
18.24 |
14.83 |
6.01 |
8.76 |
MISCIBILITY-TERNARY DIAGRAMS
Butylal is not soluble in water at 20°C.
Water is soluble in butylal up to 0.24%.
Ternary diagrams butylal - water - ethanol and butylal - water - butanol
at 23°C follow.
Ethanol and, to a lesser extent butanol, increase the miscibility of water
in butylal.
CHEMICAL PROPERTIES
Butylal is an acetal.
It undergoes the typical reactions of that group of products.
On the other hand, it does not belong to the ether group.
OLFACTORY ASPECTS
Butylal has a pleasant mild fruity smell.
PEROXIDES
Butylal at 20°C does not form any peroxides after 646 days even without
stabilizer.
HYDROLYSIS
Butylal is not miscible with water.
Hydrolysis studies have been performed by 1H NMR on 2 % w/w of butylal in
solution D2O/C2D5OD 40/60. The pH is obtained by D2SO4 97% in D2O 99,5%.
The results are the following.
| |
Percentage of hydrolysis |
| |
pH 0 |
pH 1 |
pH 2 |
| Time |
7.0 |
0 |
0 |
| 5 hours 15 days |
|
|
|
| |
31.0 |
Not measured |
Not measured |
The hydrolysis of butylal is therefore quite slow.
SALES SPECIFICATIONS
The sales specifications for butylal are as follows only one quality (in % by
weight) :
| Butylal |
98.5 % min. |
| Water |
0.2 % max. |
| Butanol |
1.0 % max. |
| Aldehydes |
0.1 % max. |
APPLICATIONS
Butylal is used as :
• cleaning solvent
• chain transfer agent in the synthesis of polyacetal resins
• reagent in various reactions
• perfumes (apple like smell)
Due to its ideal characteristics as a diesel fuel component and its high cetane
number (>73.7), butylal is widely studied as an oxygenate for diesel fuel.
At low percentages, it reduces the emission of particulates and increases the
cetane number. It can also be used as a neat fuel, producing almost no particulates
emission and reducing the emission of NO
x.
It can therefore be considered as a fuel for machines for tunnel construction
underground works or for any other applications where pollution control is particularly
important.
Butylal can also be a solvent for fragrance for diesel fuel.
Butylal can also be used as :
• SBS and SBR glues
• chain regulator in suspension polymerisation of vinyl chloride
• catalyst for polymerisation of ethylene
• foundry molding resin component (with phenolic resins and polyisocyanate)
• solvent in foundry urethane-type binder
• antifoaming agent for surfactant-containing textile-finishing baths
LABELLING
Butylal does not require any labelling.
STORAGE
Store in a cool, dry and well ventilated place.
Keep away from heat, sparks, flame and sunlight.
Keep container closed.
TRANSPORT
The transport of butylal is not regulated.
