Aqueous reactions diethanolamine

In case (1), the reaction is used for the removal of an undesirable substance from a gas stream. In this sense, the process is commonly referred to as gas absorption with reaction. Examples are removal of H2S or CO, from a gas stream by contact with an ethanolamine (e g., monoethanolamine (MEA) or diethanolamine (DEA)) in aqueous... 

V-Nitrosodiethanolamine is formed by the action of nitrosating agents (nitrites 2-bromo-2-nitropropane-l,3-diol nitrogen oxides) on diethanolamine and triethanolamine (Schmeltz Wenger, 1979 Hofimann etal, 1982 Budavari, 1998). The rate of formation of A-nitrosodiethanolamine in aqueous solutions of ethanolamines is pH-, temperature- and time-dependent. The reaction was originally thought to occur only... 

Irradiation in the presence of MDEA completely inhibits the formation of products. The amine quenches the fluorescence of Eosin with a rate constant of 8 x 108 M-1s-1 and quenches the Eosin triplet with a rate two orders of magnitude lower. A summary of rate constants for the decay of the triplet is presented in Table 8. In addition to the reactions shown in Scheme 3, with Am = (V-methyl diethanolamine, the rate constants for reaction of PDO with Eosin triplet and semioxidized Eosin radical in aqueous solution (Eqs. 19 and 20) are included in the table. 

Pinanediol esters cannot be readily displaced by treating with diethanolamine. A convenient method of removing either pinanediol esters or pinacol esters for boronic acids that are insoluble in ethers and are readily soluble in water has been developed. 34 The boronic acid ester, e.g. 21, is incubated with a hydrophobic boronic acid such as phenylboronic acid 34 in a rapidly stirred mixture of water and ether (Scheme 8). After 3 hours, the phases are separated and the aqueous phase is concentrated to give the free boronic acid 22. In this case the reaction is driven to completion by the greater solubility of the free boronic acid in the aqueous phase and the greater solubility of the pinacol ester of phenylboronate in the ether phase. This procedure has also been used to remove the pinanediol ester from Ac-D-Phe-Pro-boroArg-pinanediol 34 (see Section 15.1.7.5). 

Abstract—Gas-liquid interfacial areas a and volumetric liquid-side mass-transfer coefficients kLa are experimentally determined in a high pressure trickle-bed reactor up to 3.2 MPa. Fast and slow absorption of carbon dioxide in aqueous and organic diethanolamine solutions are employed as model reactions for the evaluation of a and kLa at high pressure, and various liquid viscosities and packing characteristics. A simple model to estimate a and kLa for the low interaction regime in high pressure trickle-bed reactors is proposed. 

Diethyl 2-hydroxy-3-(phenylamino)propylphosphonate is fonned by the reaction of diethyl 2,3-epoxypropylphosphonate with aniline at 120°C, and diethyl 2-hydroxy-3-aminopropylphosphonate is produced by the reaction with aqueous ammonia at room temperature. Ring opening at C-3 is also achieved with secondary amines such as piperidine in MeOH at 25-65°C, diethylamine at 100°C, or diethanolamine or 1,2,4-triazole in methyl ethyl ketone at 50°C in presence of a base (K2CO3, NaHCOj, CsF, or 1C X ). 

By the reaction of diethanolamine with formaldehyde (aqueous or paraformaldehyde), at 50-70 °C, the following oxazolidine (15.16) is formed with a high yield ... 

Practically, the reaction takes place by the addition of aqueous formaldehyde to a mixture of melamine suspended in diethanolamine, at a molar ratio of [melamine] [formaldehyde] [diethanolamine] = 1 3 3, followed by water distillation under vacuum, at a lower temperature of 65-75 °C, in order to avoid the viscosity increase produced by polycondensation. The maximum water accepted in the Mannich base can be high, around 5%. 

Similarly, a recent patent combines aminolysis and hydrolysis reactions for achieving polyurethane decomposition.98 Thus, scrap polyurethane is reacted with a mixture of diethanolamine and aqueous sodium hydroxide. The simultaneous attack of these agents on the polymeric chains allows the reaction time to be appreciably shortened. The reaction product, obtained as an emulsion, is subjected to a second treatment with propylene oxide in order to transform the amines and ureas present in the mixture into polyols, giving a final product which is substantially free of any hydrogen-containing nitrogen atoms. The polyols produced have been found to be particularly suitable for the preparation of fresh polyurethane polymer which can be used as an elastomer or flexible foam. 

Alkanolamines are used in scrubbers to clean streams containing acid gases. Extension of existing applications to new situations involving carbon capture and sequestration of CO2 for environmental reasons will lead to increased demand for these substances. The reaction of ammonia (A) with ethylene oxide (EO) in aqueous solution produces monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA). The reactions for stepwise formation of these products are... 

The principal of formation of this type of polyurethane elastomer medium, based on a cationic urethane latex, is where an isocyanate-terminated prepolymer derived from either a polyester or polyether diol and toluene diisocyanate is first chain-extended with an alkyl diethanolamine to yield a relatively low molecular weight urethane capable of further chain-extending reactions. Emulsification occurs when the partially extended urethane is added with high-speed mixing to 3% aqueous acetic acid. Curing of the latex takes place either by reaction of water with the terminal isocyanate groups or by reaction with water-soluble diamines. 

Experimental data on the absorption of CO2 in blends of Diethanolamine (DEA) and Piperazine (PZ) reported in the literatureare very little. The finding of additional kinetics is very much valuable. In this work, the CO2 absorption rate into aqueous solutions of mixture DEA and PZ was measured and the experimental results are presented in Fig. 1-4. The absorption flux, Rco2> was analysed using the Eq.2 and Eq.3. The pseudo-first order reaction regime assumption was verified by ealeulating Hatta... 

Additional kinetic data on the CO2 absorption rate by aqueous blends of diethanolamine (DEA) and piperazine (PZ) were obtained at 303, 313 and 323 K. The total amine concentration was varied from 0.5 to 2 M. From overall kinetics results, it is confirmed that the reaction between CO2-DEA+PZ is much faster compared to that of CO2-DEA. It was also shown that overall rate constant, kov of PZ is higher than that of DEA due to high reactivity of PZ, which is due to its cyclic and diamine characteristics. The temperature effect on the overal rate constant was assessed and expressed usiing... 

Occasionally it is found that an additive that has been extracted from a plastic will undergo a chemical change upon reaction with the extract. A case in point is that of the antistatic additive lauric diethanolamide which upon reaction with aqueous extraction liquids is hydrolysed to diethanolamine and lauric acid. In these circumstances it is not only the toxicity of lauric diethanolamide that must be considered but also that of the two hydrolysis products. In fact, it has been ascertained that during a 14 day extraction test on PP carried out at 60 "C some 100% of the extracted diethanolamide is hydrolysed ... 

The shift reaction is exothermic and thus the equilibrium is favored by low temperatures (Figure 6.2.4). Thus, the reaction temperature should be kept as low as possible, but is limited by the activity of the catalyst. The Fe-Cr shift catalyst is sufficiently active only above about 300 °C. Catalysts based on copper and zinc are active enough at about 200 °C but these catalysts are very sensitive to poisoning and require extremely pure gases, typically with less than Ippm H2S. In practice, the water-gas shift reaction is carried out in two adiabatic fixed-bed reactors with intermediate cooling between both converters. The first high-temperature shift reactor operates with a Fe-Cr catalyst, and the second low-temperature shift reactor contains the more active Cu-Zn system. At the exit of the second shift reactor, the CO2 present in the converted syngas is removed in a gas scrubber, usually by chemical absorption in aqueous amine solutions, for example, mono- or diethanolamine (Section 3.3.3). 

The Simulation or Design of a Plate Column for Absorption and Reaction The Absorption of CO2 in an Aqueous Solution of Mono- and Diethanolamine (MEA and DEA)... 

Experiments on the separation of CO2 from CH4 by the supported liquid membranes containing aqueous amines such as monoethanolamine, diethanolamine and ethylenediamine hydrochloride were performed, and tfie data were discussed quantitatively on the basis of facilitated transport theory. The effects of the chemical properties of amines such as the reaction rate constant and chemical equilibrium constant and also the effect of the CO2 partid pressure on the permeation rate of CO2 could be interpreted by the proposed theory. It was propos to use L as the effective diffusional path length in the calculation of the facilitation factor, where L is the membrane thickness and x is the tortuosity factor of the microporous support membrane. The permeation rates of CH4 was found to provide useful information for evaluating the solubilities of CO2 in the reactive membrane solutions. 

Aqueous absorbent solutions conventionally employed to Increase absorption of a species, e.g. CO2 from a gas, may have a variety of reagents, e.g. K2CO3, Na2COs, NaHC03, NaOH, monoethanolamine, diethanolamine, etc. Even without a reagent, the absorption equilibrium of a species may be affected by reaction. Absorption of SO2 into water where SO2 is ionized illustrates such a case. 

The hicilitated transport separation of CO2 from a gas mixture through an aqueous liquid membrane of diethanolamine (DEA) occurs via the following reactions ... 

A wide variety of amine condensates can function as foam boosters, wetting agents in aqueous/nonaqueous systems, emulsifiers, and dispersants. These are mainly reaction products of diethanolamine (DEA) or mono-ethanolamide (MEA) with fatty acids at a 2 1 ratio. Excess DEA converts both the amino and the amido ester to an active 2 1 product. 

Jones et al. (67) also prepared a wide range of water soluble ammonium dithiocarbamate salts, [NH4][S2CNR2] (Fig. 5). They result from the iifitial reaction of the amine with concentrated aqueous ammonia in ethanol, followed by later addition of carbon disulfide at low temperatures. For example, diethanolamine, HN(CH2CH20H)2, forms a yellow precipitate in 65% yield. Castro et al. (68) studied the kinetics and mechanism of the reactions of piperidine, pyrrolidine, morpholine, and benzylamine (69) with carbon disulfide in ethanol (Fig. 6). They proceed via a dithiocarbamic acid intermediate (4), which in turn yields the dithiocarbamate anion (5) upon proton loss to the amine. While for pyrrolidine, formation of the dithiocarbamic acid is rate determining and proceeds to the dithiocarbamate irreversibly, for both morpholine and benzylamine, the transformation is reversible. Further, in these cases the ethoxide anion is found to catalyze the transformations. They have also determined that pyrrolidine is 200 times more nucleophilic toward carbon disulfide than piperidine, despite the later being only slightly more basic, a feature that may relate to the irreversible nature of the formation of pyrrolidine dithiocarbamate. 

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