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Em virtude da necessidade de se quantificar os carbamatos provenientes de processos de absorção química do gás CO2 por monoetanolamina (MEA) e dietanolamina (DEA), curvas analíticas por espectroscopia no infravermelho (IV) foram construídas visando à determinação do teor de carbamatos de MEA e DEA, além da quantificação de MEA, DEA e metildietanolamina (MDEA) em soluções puras e em misturas. O procedimento analítico compreendeu o preparo das amostras-padrão constituintes das curvas de calibração e suas quantificações com o emprego de técnicas instrumentais de referência titulação potenciométrica, pesagem e GC-FID. As amostras-padrão de aminas puras foram quantificadas por titulação potenciométrica, sendo possível a detecção exata do ponto de equivalência. As composições dos padrões analíticos de misturas foram estabelecidas segundo um diagrama triangular para misturas e o teor de cada componente foi determinado por gravimetria e GC-FID. Tanto a hidrólise quanto a degradação térmica dos carbamatos foram fatores que restringiram o emprego da titulação potenciométrica, HPLC-MS/MS e GC-FID como técnicas de referência em suas quantificações. Essas restrições, somadas ao fato de não haver disponibilidade comercial desses carbamatos, levaram ao uso da espectroscopia de RMN de 1H na determinação quantitativa. As curvas de calibração apresentaram ótimo ajuste dos valores preditos com relação aos de referência e erro máximo de predição de 0,594 %. Dois processos de absorção química do gás CO2 foram realizados em escala semipiloto e os resultados obtidos foram de 1,02 % e 0,98 % de CO2 absorvido por solução de MEA e DEA, respectivamente. Os mesmos processos foram simulados no software Aspen Plus, obtendo-se 1,18 % de CO2 absorvido por solução de MEA e 1,00 % por solução de DEA. / Due to the need to quantify carbamates from the CO2 gas chemical absorption process by monoethanolamine (MEA) and diethanolamine (DEA), analytical curves by IR spectroscopy were obtained with the aim of quantifying MEA and DEA carbamates and MEA, DEA and methyldiethanolamine (MDEA) in pure solutions and mixtures. The analytical procedure considered the preparation of standard samples constituents of the calibration curves and their quantification using reference instrumental techniques potentiometric titration, gravimetry and GC-FID. The standard samples of pure amines were quantified by potentiometric titration, getting the accurate detection of the equivalence point. The compositions of the analytical standards of the mixtures were established according to a triangular diagram for mixtures and the content of each component was determined by gravimetry and GC-FID. The carbamate hidrolysis and its thermal degradation were factors that limited the use of potentiometric titration, HPLCMS/ MS and GC-FID as reference techniques in their quantitation. These restrictions, added to the fact of not having commercial availability of these carbamates, led the use of 1H NMR spectroscopy for the quantitative determination. The calibration curves resulted in an excellent adjustment of the expected values related to the reference values and maximum error of prediction of 0.594 %. Two chemical absorption processes of CO2 gas were performed in semi-pilot scale and the obtained results were of 1.02 % and 0.98 % of absorbed CO2 by MEA and DEA solutions, respectively. Both processes were simulated using Aspen Plus software, presenting 1.18 % of CO2 absorbed by MEA solution and 1.00 % by DEA solution.

Em virtude da necessidade de se quantificar os carbamatos provenientes de processos de absorção química do gás CO2 por monoetanolamina (MEA) e dietanolamina (DEA), curvas analíticas por espectroscopia no infravermelho (IV) foram construídas visando à determinação do teor de carbamatos de MEA e DEA, além da quantificação de MEA, DEA e metildietanolamina (MDEA) em soluções puras e em misturas. O procedimento analítico compreendeu o preparo das amostras-padrão constituintes das curvas de calibração e suas quantificações com o emprego de técnicas instrumentais de referência titulação potenciométrica, pesagem e GC-FID. As amostras-padrão de aminas puras foram quantificadas por titulação potenciométrica, sendo possível a detecção exata do ponto de equivalência. As composições dos padrões analíticos de misturas foram estabelecidas segundo um diagrama triangular para misturas e o teor de cada componente foi determinado por gravimetria e GC-FID. Tanto a hidrólise quanto a degradação térmica dos carbamatos foram fatores que restringiram o emprego da titulação potenciométrica, HPLC-MS/MS e GC-FID como técnicas de referência em suas quantificações. Essas restrições, somadas ao fato de não haver disponibilidade comercial desses carbamatos, levaram ao uso da espectroscopia de RMN de 1H na determinação quantitativa. As curvas de calibração apresentaram ótimo ajuste dos valores preditos com relação aos de referência e erro máximo de predição de 0,594 %. Dois processos de absorção química do gás CO2 foram realizados em escala semipiloto e os resultados obtidos foram de 1,02 % e 0,98 % de CO2 absorvido por solução de MEA e DEA, respectivamente. Os mesmos processos foram simulados no software Aspen Plus, obtendo-se 1,18 % de CO2 absorvido por solução de MEA e 1,00 % por solução de DEA. / Due to the need to quantify carbamates from the CO2 gas chemical absorption process by monoethanolamine (MEA) and diethanolamine (DEA), analytical curves by IR spectroscopy were obtained with the aim of quantifying MEA and DEA carbamates and MEA, DEA and methyldiethanolamine (MDEA) in pure solutions and mixtures. The analytical procedure considered the preparation of standard samples constituents of the calibration curves and their quantification using reference instrumental techniques potentiometric titration, gravimetry and GC-FID. The standard samples of pure amines were quantified by potentiometric titration, getting the accurate detection of the equivalence point. The compositions of the analytical standards of the mixtures were established according to a triangular diagram for mixtures and the content of each component was determined by gravimetry and GC-FID. The carbamate hidrolysis and its thermal degradation were factors that limited the use of potentiometric titration, HPLCMS/ MS and GC-FID as reference techniques in their quantitation. These restrictions, added to the fact of not having commercial availability of these carbamates, led the use of 1H NMR spectroscopy for the quantitative determination. The calibration curves resulted in an excellent adjustment of the expected values related to the reference values and maximum error of prediction of 0.594 %. Two chemical absorption processes of CO2 gas were performed in semi-pilot scale and the obtained results were of 1.02 % and 0.98 % of absorbed CO2 by MEA and DEA solutions, respectively. Both processes were simulated using Aspen Plus software, presenting 1.18 % of CO2 absorbed by MEA solution and 1.00 % by DEA solution.

Aqueous amine solutions loaded with CO2 were degraded in stainless steel sealed containers in forced convection ovens. Amine loss and degradation products were measured as a function of time by cation chromatography (IC), HPLC, and IC/mass spectrometry. A full kinetic model was developed for 15-40 wt% MEA (monoethanolamine) with 0.2 – 0.5 mol CO2/mol MEA at 100°C to 150°C. Experiments using amines blended with MEA demonstrate that oxazolidone formation is the rate-limiting step in the carbamate polymerization pathway. With 30 wt% MEA at 0.4 mol CO2/mol MEA and 120°C for 16 weeks there is a 29% loss of MEA with 13% as hydroxyethylimidazolidone (HEIA), 9% as hydroxyethylethylenediamine (HEEDA), 4% as the cyclic urea of the MEA trimer, 1-[2-[(2-hydroxyethyl)amino]ethyl]-2-imidazolidone, 3% as the MEA trimer, 1-(2-hydroxyethyl)diethylenetriamine, and less than 1% as larger polymeric products. In the isothermal experiments, thermal degradation was slightly more than first order with amine concentration and first order with CO2 concentration with an activation energy of 33 kcal/mol. In a modeled isobaric system, the amount of thermal degradation increased with stripper pressure, but decreased with an increase in amine concentration and CO2 concentration due to a reduction in reboiler temperature from the changing partial pressure of CO2. Three-fourths of thermal degradation in the stripper occurred in the reboiler due to the elevated temperature and long residence time which offset the decrease in CO2 concentration compared to the packing. The amount of degradation for other amines tested starting with the least degraded include; cyclic amines with no side chains < long chain alkanolamines < alkanolamines with steric hindrance < tertiary amines < MEA < straight chain di- and triamines. Piperazine and morpholine had no measurable thermal degradation under the conditions of this experiment and were the most resistant to thermal degradation. Diethyelenetriamine and HEEDA had the largest amount of degradation with over 90% loss at 135°C for 8 weeks. / text

O processo de absorção do CO2 em soluções aquosas de alcanolaminas foi estudado em uma coluna de parede molhada empregando-se uma tela metálica, de 28 mesh, como promotor de película e operando em contracorrente. As alcanolaminas testadas nos diferentes experimentos foram: monoetanolamina (MEA), 2-amino-2-metil-1-propanol (AMP) e piperazina (PZ). Os experimentos de absorção foram realizados nas soluções aquosas individuais da MEA e AMP; e, nas misturas MEA:AMP e AMP:PZ; visando avaliar a velocidade de absorção do CO2 em diferentes vazões do líquido, a saber: 3.10-7, 6.10-7 e 10.10-7 m3/s. O presente sistema de absorção foi caracterizado através da determinação dos principais parâmetros de transferência de massa: área interfacial efetiva, coeficiente de transferência individual da fase gasosa e o coeficiente volumétrico global médio de transferência de massa. Determinou-se a área interfacial efetiva da coluna, por meio da absorção do CO2 diluído em ar em uma solução aquosa de NaOH, para as diferentes vazões de líquido, sendo os resultados obtidos igual a 106, 126 e 144 m2/m3, respectivamente. O coeficiente volumétrico de transferência de massa da fase gasosa foi determinado por meio da absorção de SO2 diluído em ar em uma solução aquosa de NaOH. Os resultados experimentais mostram que o coeficiente volumétrico individual de transferência de massa e a área interfacial são função da vazão do líquido. As velocidades de absorção do CO2 diluído em ar, em soluções de aminas e suas misturas foram determinadas experimentalmente para diferentes vazões de líquido, sendo os resultados expressos na forma de coeficientes globais de transferência de massa e parâmetros cinético-difusivos da fase líquida. As velocidades de absorção em MEA são bem superiores aos de AMP e NaOH. No caso das misturas foram obtidas velocidades superiores em comparação às das aminas individuais. A velocidade de absorção em AMP é fortemente incrementada na presença de PZ, mesmo em baixa concentração. / The CO2 absorption process in alkanolamine aqueous solutions was studied in a wetted wall column employing a film promotor of thin stainless steel woven wire, 28 mesh, which was operated in countercurrent. The tested alkanolamines were monoethanolamine (MEA), 2-amino-2-methyl-1-propanol (AMP) and piperazine (PZ). The absorption experiments were performed in individual aqueous solutions of MEA and AMP and the mixtures MEA:AMP and AMP:PZ, with the aim of evaluating the CO2 absorption rate in different liquid flow rates, namely: 3.10-7, 6.10-7 e 10.10-7 m3/s. This absorption system was characterized through determining of the main parameters of mass transfer: effective interfacial area, individual mass transfer coefficient of the gas phase and the average overall mass transfer volumetric coefficient. The effective interfacial area was determined by the absorption of CO2 diluted in air into an aqueous solution of NaOH for the different liquid flow rates, and the results obtained are 106, 126 and 144 m2/m3, respectively. The mass transfer volumetric coefficient of the gas phase was determined by chemical method of the absorption of SO2 diluted in air into an aqueous solution of NaOH. The experimental results show that the individual mass transfer coefficient and interfacial area are a function of liquid flow rate. On the other hand, the results of the performance of CO2 absorption into amine aqueous solutions were expressed in function of the average overall mass transfer volumetric coefficient and liquid phase diffusive kinetic parameters, which were measured experimentally for different liquid flow rates. The absorption rate in MEA are higher in comparison with AMP and NaOH. In the case of the blended, the absorption rate in AMP is enhanced by piperazine, even in low concentration.

O processo de absorção do CO2 em soluções aquosas de alcanolaminas foi estudado em uma coluna de parede molhada empregando-se uma tela metálica, de 28 mesh, como promotor de película e operando em contracorrente. As alcanolaminas testadas nos diferentes experimentos foram: monoetanolamina (MEA), 2-amino-2-metil-1-propanol (AMP) e piperazina (PZ). Os experimentos de absorção foram realizados nas soluções aquosas individuais da MEA e AMP; e, nas misturas MEA:AMP e AMP:PZ; visando avaliar a velocidade de absorção do CO2 em diferentes vazões do líquido, a saber: 3.10-7, 6.10-7 e 10.10-7 m3/s. O presente sistema de absorção foi caracterizado através da determinação dos principais parâmetros de transferência de massa: área interfacial efetiva, coeficiente de transferência individual da fase gasosa e o coeficiente volumétrico global médio de transferência de massa. Determinou-se a área interfacial efetiva da coluna, por meio da absorção do CO2 diluído em ar em uma solução aquosa de NaOH, para as diferentes vazões de líquido, sendo os resultados obtidos igual a 106, 126 e 144 m2/m3, respectivamente. O coeficiente volumétrico de transferência de massa da fase gasosa foi determinado por meio da absorção de SO2 diluído em ar em uma solução aquosa de NaOH. Os resultados experimentais mostram que o coeficiente volumétrico individual de transferência de massa e a área interfacial são função da vazão do líquido. As velocidades de absorção do CO2 diluído em ar, em soluções de aminas e suas misturas foram determinadas experimentalmente para diferentes vazões de líquido, sendo os resultados expressos na forma de coeficientes globais de transferência de massa e parâmetros cinético-difusivos da fase líquida. As velocidades de absorção em MEA são bem superiores aos de AMP e NaOH. No caso das misturas foram obtidas velocidades superiores em comparação às das aminas individuais. A velocidade de absorção em AMP é fortemente incrementada na presença de PZ, mesmo em baixa concentração. / The CO2 absorption process in alkanolamine aqueous solutions was studied in a wetted wall column employing a film promotor of thin stainless steel woven wire, 28 mesh, which was operated in countercurrent. The tested alkanolamines were monoethanolamine (MEA), 2-amino-2-methyl-1-propanol (AMP) and piperazine (PZ). The absorption experiments were performed in individual aqueous solutions of MEA and AMP and the mixtures MEA:AMP and AMP:PZ, with the aim of evaluating the CO2 absorption rate in different liquid flow rates, namely: 3.10-7, 6.10-7 e 10.10-7 m3/s. This absorption system was characterized through determining of the main parameters of mass transfer: effective interfacial area, individual mass transfer coefficient of the gas phase and the average overall mass transfer volumetric coefficient. The effective interfacial area was determined by the absorption of CO2 diluted in air into an aqueous solution of NaOH for the different liquid flow rates, and the results obtained are 106, 126 and 144 m2/m3, respectively. The mass transfer volumetric coefficient of the gas phase was determined by chemical method of the absorption of SO2 diluted in air into an aqueous solution of NaOH. The experimental results show that the individual mass transfer coefficient and interfacial area are a function of liquid flow rate. On the other hand, the results of the performance of CO2 absorption into amine aqueous solutions were expressed in function of the average overall mass transfer volumetric coefficient and liquid phase diffusive kinetic parameters, which were measured experimentally for different liquid flow rates. The absorption rate in MEA are higher in comparison with AMP and NaOH. In the case of the blended, the absorption rate in AMP is enhanced by piperazine, even in low concentration.

Isocyanates, aromatic-, aliphatic- and alkanolamines are commonly used in the industry today. Millions of workers in Europe are exposed. The most frequent health symptoms are respiratory and dermal disorder. Due to the health risk most of the compounds in this thesis are regulated by authorities and have occupational exposure limits (OELs). Consequently, reliable and robust air sampling methods are urgently needed. In this thesis dry samplers for isocyanates, aliphatic- and alkanolamines have been developed and evaluated. The isocyanate sampler is now a commercial product (ASSET EZ4-NCP Dry Sampler, Supelco). The samplers were based on a denuder with a filter in series. The denuder and filter were impregnated with di-n-butylamine for the isocyanate sampler and with sulphuric acid for the aliphatic- and alkanolamine sampler. The robustness of the dry samplers was extensively evaluated. This was performed in a climate chamber containing a controlled atmosphere of the studied compounds. New methods based on hydrophilic interaction liquid chromatography (HILIC) coupled with tandem mass spectrometry (MSMS) were developed for determination of aromatic-, aliphatic- and alkanolamines in aqueous solutions. Isocyanates were determined by reversed-phase liquid chromatography MSMS. HILIC in combination with MS is a most powerful system, and highly sensitive determinations, several orders of magnitude below the OELs, of polar compounds present in the work environment can be accomplished. The selected samplers enable sampling during short sampling times and for whole work shifts. The samplers can be stored for months before and after sampling. The performance of the samplers was unaffected by variation in temperature, humidity, flow-rate and pre- and post-sampling of ambient air. Sampling for the compounds studied is now greatly simplified, and assessment of the work environment is facilitated. / <p>At the time of the doctoral defence the following papers were unpublished and had a status as follows: Paper 1: Epub ahead of print; Papers 3-5: Manuscripts</p>