DBU®
DBU is one of the most strongly basic organic
compounds. Since the first industrial production of a compound with this
structure by San-Apro Ltd. in 1967, it has been favored for its strong
basicity, which is sufficient to replace sodium hydroxide, and many
researchers have introduced a number of characteristic reactions have
been introduced by many researchers. The stability of DBU, its super
strong base properties and its wide range of solubility in organic
solvents give it high catalytic activity, mild reaction conditions and
high selectivity for the target product in various organic synthesis
reactions, and even now, new applications are being discovered one after
another, and many reports are being published.
There are some differences in the
numerical values that indicate the strength of DBU's basicity depending
on the measurement conditions, but the values in Table 1 are known.
The expression of this basicity
is thought to be due to the contribution of the resonance-stabilized
structure shown on the left, as determined by the shape of the protons
of the 6th, 2nd, 9th and 11th carbons in NMR.
Chemical properties of DBU
It reacts as a monovalent tertiary
amine, forming stable salts with acids and quaternary ammonium salts
with alkyl halides. It can be used in a wide range of organic synthesis
fields, including reactions involving the elimination of acids and
hydrogen halides, cycloaddition reactions, reactions with isocyanates,
Wittig reactions, Michael addition reactions, ring-opening reactions,
esterification reactions, oxime formation reactions, reactions with
olefins, and various reactions mediated by DBU metal complexes.
Reaction behavior of DBU itself
Hydrolysis: Undergoes gradual hydrolysis in the presence of
water,
especially at high humidity.
DBN
Along with DBU, it is one of the strongest organic
bases; like DBU, it can be widely applied to various reactions.
When used as a curing catalyst and accelerator for epoxy resins,
it can produce subtle differences in physical properties in products
compared to DBU;
used in a complementary manner to DBU; can be used in a
complementary manner to DBU;
can be used in a complementary manner to epoxy resins.
Physical properties of DBU
DBU is a colorless to pale yellow
liquid with a faint amine odor. It is soluble in most organic solvents
and water, with the exception of a few solvents such as petroleum
ether.
- Appearance: Colorless to
slightly yellowish liquid
- Molecular weight: 152.14
- Density: 1.04
g/ml
- Refractive index: 1.52
- Flash point (C O.C.): 109°C
- Boiling
point：259～260℃ /1013 hPa
- Odor: slight amine odor
- pH：13.4（10% aq
soln.）
- pKa：12.5
Solubility
of DBU
DBU is soluble in almost all organic solvents used in everyday life,
and can be reacted using any solvent.
Soluble: Water, ethyl alcohol, benzene, acetone, ethyl acetate, ether,
dioxane, 1, 4-butanediol, DMSO, liquid ammonia, polyether polyol
Insoluble: Petroleum ether
Laws and safety information
regarding DBU
- Chemical
name：Chemical name：1・8-Diazabicyclo (5・4・0) undec-7-ene
- Chemical
Substances Control Law: Existing Chemical Substances Control Law
number：（5） 1117
- Occupational Safety and Health Law: Existing
(Chemical Substances Control Law public notice substances up to June
29.1979) Article 2
- Fire Service Act: Hazardous Materials、 Class 4、
Petroleums No. 3、 Hazardous Rank、Water-soluble
- Ship Safety Act:
Hazardous Materials Regulations: Corrosive substance. UN No.: 1760
- TSCA: Listed
- CAS No.： 6674-22-2
- Acute toxicity: LDso＝836 mg／kg、
oral、rat
- Mutagenicity: Not recognized
- Ames Test: Negative
- Irritation: There is a risk of irritation to the eyes、 skin、
respiratory tract、 etc.、 which may cause corrosion.
