Preparation of secondary amines
A kind of secondary amine, primary amine technology, applied in the catalysis field of amine alkylation, can solve problems such as low amine conversion rate
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Embodiment 1
[0039] Example 1 - Preparation of N-isopropyl-N', N'-dimethyl-1,3-propanediamine
[0040] 580 g / h of dimethylaminopropylamine (“DMAPA”) and 420 g / h of acetone were simultaneously fed to a jacketed stainless steel tubular upflow reactor (volume 600 cc) with an internal diameter of 1.338″ and equipped with a thermowell (upstream), wherein said thermowell extends upwards into the reactor, made of a pipe of 0.25 O.D. The packed bed of nickel catalyst disclosed in US3151112 and US3654370 is housed in the reactor tube. The add-on ratio of hydrogen is chemical The metered excess was about 100%. The reaction was carried out at a pressure of 1500 psig and a temperature of 135°C. After a single pass through a tubular reactor about 30" long, analysis of the reactor effluent showed about 85% N-iso Propyl-N',N'-dimethyl-1,3-propanediamine, 6% unreacted DMAPA, 1% diisopropylDMAPA and 2% coupled product. Furthermore, diisopropylDMAPA cannot be separated from DMAPA during the subsequent di...
Embodiment 2
[0041] Example 2 - Preparation of N-isopropyl-N', N'-dimethyl-1,3-propanediamine
[0042] The procedure of Example 1 was repeated, except that the previously used nickel catalyst was replaced by a 1% palladium catalyst supported on carbon (Engelhard), and the reaction temperature was lowered to 120°C. Analysis of the effluent showed an approximately 97% yield of N-isopropyl-N',N'-dimethyl-1,3-propanediamine, with no significant diisopropylDMAPA or coupling products detected. Distillation of the effluent yielded 99.5% pure N-isopropyl-N',N'-dimethyl-1,3-propanediamine.
Embodiment 3
[0043] Example 3 - Preparation of N, N'-diisopropylisophoronediamine
[0044] About 300 g / h of isophoronediamine and 450 g / h of acetone were fed upflow into a 600 cc packed bed reactor charged with nickel catalyst as described in Example 1 above. About 100% excess hydrogen was added. Reactions were run at 2000 psig and 140°C. The reactor effluent was stripped of light components under reduced pressure. The resulting product was analyzed to contain 8.78 meq / g total amines and 3.557 meq / g primary amines. The above results indicated that a significant amount (40.5%) of the primary amine groups remained unalkylated. In addition, GC analysis indicated the presence of about 2.00% "heavy components". That is to say, coupling of amines takes place.
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