DABCO triethylene diamine

Triethylene diamine (TEDA also known as l,4-diazabicyclo[2.2.2]octane, or DABCO) is a powerful catalyst with a high selectivity for gellation. One reason... 

DABCO = l,4-diazabicyclo[2,2,2]octane (triethylene diamine) (22) is a moderately basic amine, removable by sublimation, that causes enantiomeriza-tion of amino acid residues that have been reacted to form Schiff s bases (RR C=NCHR2CO-). 

DABCO 33 LV is also known as triethylene diamine. It is a cage-like compound with no steric hindrance (Figure 2.39), which helps make it a very effective catalyst. It is reactive at close to ambient temperatures. The application range is in the range of 0.3 to 0.6 parts per 100 of prepolymer. To obtain the desired rate, a mixture of an acid (such as oleic) with a bismuth catalyst can be used. Bismuth catalysts include bismuth neodecanoate and bismuth ocotate. 

Tertiary amines are catalysts for both isocyanate-hydroxyl and isocyanate-water reactions. Generally, an increase in base strength in tertiary amines increases the catalytic strength. However, in the case of triethylene diamine (DABCO) the nucleophilicity is enhanced by the steric configuration. Electron-donating substituents enhance catalytic activity. Some tertiary amines are illustrated in Figure 2.20. 

Figure 2. Second-order plot of reaction of diisocyanates and water in cellosolve acetate catalyzed by triethylene diamine at 50°C [RfNCO) .] = 0.12 g mol/kg [H,0] = 0.12 g mol/L [Dabco] = 0.004 g mol/L. Key , PPD1 O, MD1 CHDI , IPD1 A, HMDI A, NDI.

The catalyst used was Dabco 33LV (triethylene diamine). Preliminary studies indicate that Dabco 33LV is an efficient catalyst for HER. Although there is indication of good stability of 33LV in HER, the true stability and retention of activity are unknown. 

Dabco 33LV 33% Solution of triethylene diamine in dipropylene glycol Air Products... 

Bases accelerate all the isocyanate reactions and in general their catalytic effect increases with increasing strength of the base. Table 4.7 compares the action of several amine catalysts at near ambient temperature. The significant increase in urethane reaction rate is apparent but particularly so in the case of triethylene diamine (l,4-diazo-[2,2,2]-bicyclo-octane), commonly known as DABCO. The reason for this is probably the complete lack of steric hindrance, given its cage-like structure. 

Another important polymer catalyst development was triethylene diamine (TEDA), trademarked Dabco by the Houdry Process Corp. in 1959 as a one-step catalyst for poljuirethanes. In 1956, Houdry had made this unusual compound as a by-product of research directed toward synthesis of heterocyclic nitrogen compounds using silica-alumina cracking catalysts. The use of TEDA as a urethane catalyst was suggested by Professor Milton Orchin of the University of Cincinnati it was developed by Houdry researchers led by Adalbert Farkas. Dabco soon became the major urethane catalyst (85). 

Later, both the methods have been studied and compared, the addition reaction of various diisocyanates and dithiols carried out in chlorobenzene/o-dichlorobenzene solution with tri- -propylamine [102-69-2] and DABCO (1,4-diazabicyklo[2.2.2.]octane, triethylene diamine, 2,2 -diazabicyclo[2.2.2]octane, TED, BACO) [280-57-9] as catalyst (eq. 5) and interfacial condensation of... 

Dabco is the trade name for triethylene diamine (Jacobson and Van den Burg and Co. (U.K.) Ltd, 3-5 Crutched Friars, London, E.C.3). Weigh out 6 0.1 g Dabco and transfer to an over-dried 1 litre volumetric flask. Add dry toluene (less than 15 ppm water) from the dispenser (see Figure 7.12) to make the volume up to approximately 950 cm Dissolve the Dabco by shaking and stand the flask in a water bath thermostatted at 25 + rC. When the solution has reached 25°C make up to the 1 dm mark with dry toluene and mix thoroughly. Stand the solution in a water bath, thermostatted at 25 + rC. A measured volume of this solution then contains a constant weight of Dabco catalyst. 

In general, when a small pillar, such as triethylene diamine (DABCO), is employed, the 3D network is seldom... 

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