The molecular structure of asphaltene: an unfolding story

Strausz, O. P.; Mojelsky, Thomas W.; Lown, E. M.

doi:10.1016/0016-2361(92)90206-4

Cited by 319 publications

(332 citation statements)

References 19 publications

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“…An improved Brown-Ladner method was adopted to calculate the molecular structures of resins and asphaltenes with the data of elemental analysis, average molecular weight, and 1 H-NMR (Suzuki et al 1982;Ali et al 1990;Strausz et al 1992). The calculated results are listed in Table 7.…”

Section: Changes Of the Molecular Structures Of Asphaltenes And Resinsmentioning

confidence: 99%

Catalytic aquathermolysis of Shengli heavy crude oil with an amphiphilic cobalt catalyst

2016

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An interfacially active cobalt complex, cobalt dodecylbenzenesulfonate, was synthesized. Elemental analysis, atomic absorption spectroscopy, Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis, and surface/interfacial tension determination were performed to investigate the properties of the catalyst. Results showed that the synthesized catalyst showed active interfacial behavior, decreasing the surface tension and interfacial tension between heavy oil and liquid phase to below 30 and 1.5 mN/m, respectively. The catalyst was not thermally degraded at a temperature of 400°C, indicating its high thermal stability. Catalytic performance of the catalyst was evaluated by carrying out aquathermolysis. The viscosity determination showed that the viscosity of the heavy oil decreased by 38 %. The average molecular weight, group compositions, and average molecular structure of various samples were analyzed using elemental analysis, FT-IR, electrospray ionization Fourier transform ion cyclotron resonance (ESI FT-ICR MS), and 1 H nuclear magnetic resonance. Results indicated that the catalyst could attack the sulfur-and O 2 -type heteroatomic compounds in asphaltene and resin, especially the compounds with aromatic structure, leading to a decrease in the molecular weight and then the reduction in the viscosity of heavy oil. Therefore, the synthesized catalyst might find an application in catalytic aquathermolysis of heavy oil, especially for the high-aromaticity heavy oil with high oxygen content.

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Section: Changes Of the Molecular Structures Of Asphaltenes And Resinsmentioning

confidence: 99%

Catalytic aquathermolysis of Shengli heavy crude oil with an amphiphilic cobalt catalyst

2016

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“…34,[36][37][38] A presença de sais alcalinos, junto com o pH, deve ser responsável pelas sensíveis variações na estabilidade das emulsões de frações contendo ácidos naftênicos. [39][40][41][42] Os ácidos naftênicos presentes em asfaltenos formam um sistema difícil de analisar por técnicas espectroscópicas, já que a banda de absorção registrada tem um valor comum à de compósito. 43 As reações mais importantes para estes compostos são amidação, esterificação, formação de sais metálicos, reações com imidazolinas e outros derivativos.…”

Section: Propriedades Dos áCidos Naftênicosunclassified

Ácidos naftênicos no petróleo

Gruber¹,

Damasceno²,

Caramão³

et al. 2012

Quím. Nova

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Recebido em 22/7/11; aceito em 5/2/12; publicado na web em 15/5/12 NAPHTHENIC ACIDS IN PETROLEUM. Brazilian petroleum is known by its high acidity due to the presence of acidic constituents, especially naphthenic acids (NA). The total characterization of the NA in petrochemical samples has been receiving special attention in research and comprises an analytical challenge, mainly due to the complexity of their mixtures. Gas chromatography with mass detector (GC/MS) is the technique of analysis more used, but recently comprehensive two-dimensional gas chromatography (GC × GC) has been used, due to its high resolution, peak capacity and sensitivity. The goal of this article is to discuss the techniques for sample preparation and analysis of NA in petroleum.Keywords: petrochemicals samples; naphthenic acids; characterization of the NA. INTRODUÇÃONos últimos anos grande parte das reservas de petróleo descobertas em território brasileiro consiste de óleo pesado de baixo grau API (<20º), alta viscosidade e elevada acidez total. 1 A Empresa de Petróleo Brasileiro S/A, PETROBRAS, visando viabilizar a comercialização do petróleo vem investindo em programas de pesquisa e desenvolvimento, tais como, PRAVAP (Programa de Recuperação Avançada de Petróleo), PROTER (Programa de Tecnologias Estratégicas de Refino) e PROPES (Programa Tecnológico de Óleos Pesados).As fontes de óleo cru na América do Sul, incluindo o petróleo brasileiro, estão entre as mais ácidas do mundo.2,3 Tal acidez é responsabilizada por muitas dificuldades na utilização desta matéria-prima nas refinarias e no aproveitamento de seus resíduos.Os ácidos naftênicos (AN) são encontrados, predominantemente, em óleos imaturos, biodegradados, em óleos pesados e águas residuá-rias geradas no processo de extração do betume.4,5 Sua importância é salientada em geoquímica, aplicações comerciais, aspectos ambientais e corrosão. [2][3][4][5][6] O termo naftênico, correspondente a compostos cíclicos saturados, é usado para todos os tipos de ácidos encontrados em petróleos, mesmo os saturados lineares e os ramificados. 2,5,7 Os ácidos carboxílicos presentes no petróleo representam um grande problema para o refino e craqueamento do mesmo, devido ao seu efeito corrosivo em linhas de transferência de massa e calor, nas seções de entrada e refluxo de colunas (à pressão atmosférica e a vácuo) e nos condensadores das unidades de destilação das refinarias. 5 De forma geral, determina-se o teor de ácidos através da titulação com KOH, obtendo-se então o índice ou número de acidez naftênica. Este índice pode ser indicativo de atividade corrosiva da amostra, contudo, nada acrescenta quanto à qualidade do petróleo e à natureza dos ácidos presentes. Para caracterizar estes ácidos, é necessário extraí-los e analisá-los de forma individual. 2,5 O petróleo é constituído de uma mistura complexa de hidrocarbonetos com quantidade bastante significativa de isômeros, além destes, apresenta compostos contendo nitrogênio, oxigênio e enxofre, que dificultam as etapas de extração, isolamento e caract...

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“…This restriction places an upper bound on the largest molecular weight that an asphalt or asphaltene aggregate can attain, which is about 6000 -8000. h the literature, one finds estimates of the average molecular However, what we are interested in here is the MW distribution of the aggregates after a long time. Over the years, many authors have studied this problem Boduszynski et al, 1977;Speight and Moschopedis, 1977;Speight et al, 1985;Boduszynski , 1988Acevedo et al, 1992;Strausz et al, 1992;Trauth et al, 1994). Aside from Trauth et al (1994), these authors measured mainly the average MW of asphalts and asphaltenes from various oils, and provided some statistics of their measurements, but none proposed an analytical formula for the MW distribution, and in fact they did not even give the full MW distribution itself.…”

Section: Kinetics Of Aggregation Of the Asphalt Particlesmentioning

confidence: 99%

“…Over the years, many models have been proposed, beginning perhaps with the work of co-workers (1967, 1969), in which an analogy to polymers was proposed. Many other conceptual models have been proposed (see, for example, Yen, 1974;Sakai et al, 1983;Boduszynski, , 1988Strausz et al, 1992). In particular, an interesting model has been proposed by Klein and co-workers Truath et aL, 1994), in which the experimental knowledge about the chemical structure of asphaltenes has been used for developing a model that combines experimental data and an iterative stochastic method for generating a model of asphaltenes.…”

Section: Scaling Analysis Of the Precipitation Datamentioning

confidence: 99%