The acetylacetone (acac) method is based on the Hantzsch synthesis, where 2,4-pentanedione
(acac), ammonium acetate, and formaldehyde are cyclized to form dihydropyridine 3,5-diacetyl-1,4-dihydrolutidine (DDL).
30% HCl Suprapur (Merck, Darmstadt, Germany), acetone (Sigma-Aldrich), 2,4-pentanedione
99% (Alfa Aesar, Karlsruhe, Germany), and 37% HCl (Riedel-de Haen) were commercially available and used as received.
To prepare each formulation, the resins, solvents, catalyst (dibutyltindiacetate), and pot life extender (2,4-pentanedione
) were mixed.
Knoevenagel condensation of selected aromatic aldehydes with 2,4-pentanedione
in dry benzene catalyzed by piperidine gave 3-arylidenepentane-2,4-dione derivatives 109.
Elastosil, Silres, HDK, Vinnapas, Vinnol, Geniosil, Cavamax, Cavasol, Wacker, silicones, elastomers, VAE, cyclodextrins, silica, coatings, adhesives, silicone resins, dispersions, binders, antifoam, theological modifiers, thixotropic, leveling agent, rubber, acetyl acetone, 2,4-pentanedione
, industrial coating, masonry coating, paper coating, architectural coating, sealant, marine coating, paints and plasters, additives, anti-corrosion coatings, heat resistant coatings, low VOC.
Ethylene carbonate (EC), 2,4-pentanedione
, ethyl 3-ethoxypropionate (EEP), dibutyltin diacetate (DBTDAc), tin(II) 2-ethylhexanoate, methylene iodide (MI), benzyltrimethylammonium hydroxide (40% solution in methanol), methyl isobutyl ketone (MIBK), and HPLC grade water were purchased from Aldrich.
Formaldehyde was measured continuously, using the automated Dasgupta-diffusion-tube sampler to obtain aqueous formaldehyde, which is then mixed with buffered 2,4-pentanedione
and measured with fluorescence (Dasgupta et al, 1988).
The concentration of CoNap, Trigonox and 2,4-Pentanedione
was systematically varied.
* Catalyst savings: Formulations are simpler because no 2,4-pentanedione
retarder is needed, and amine accelerators can be eliminated, except perhaps in very thin layers or in cold weather.
Six classes of organic solvents were examined: Alcohol (isopropyl), ketones (acetone and 2,4-pentanedione
), aliphatic hydrocarbon (iso-octane), aromatic hydrocarbon (xylene), chlorinated olefin (trichloroethylene), chlorinated aromatic (chlorobenzene and O-dichlorobenzene), heterocyclic base (pyridene), and fluorinated solvent (trichlorotrifluoroethane).
Butyl methacrylate (BMA), n-butyl acrylate (BA), 2-hydroxyethyl acrylate (HEA), dibutyltin diacetate (DBTDA), 2,4-pentanedione
, and methyl isobutyl ketone (MIBK) were obtained from Aldrich.
This paper reports on 1) the effects of a promoter (cobalt naphthenate] on the initiation at low temperatures, and 2) the effects of a retarder (2,4-pentanedione
) and an inhibitor (1,4-benzoquinone) on the pot life, gel time, and cure kinetics.