Aggregation Of Novelly Synthesized Phthalocyanines And Effect On Association Of Heavy Petroleum Fractions

Petroleum is commonly described as an extremely complex mixture.The interests on the complex colloidal dispersion and its stability are growing,especially the asphaltene supramolecular aggregate which is closely related to the stability of petroleum.The crude oil was considered to have colloidal structure initially.And the structure of the"association"and"cluster"was later proposed.The new supramolecular model of the composition of heavy oil at the molecular level has been proposed recently.These insights are reflected the deeper understanding on the petroleum chemistry with the development of scientific and technological.At present,a lot of progress on the research of structure of the supramolecular aggregates of petroleum has been made,but there is still a lot of work to be done at the molecular level.One method to improve our understanding of association behavior of asphaltenes in solution is to synthesize pure compounds that contain selected chemical structures,and then to examine their behavior in solution.This is an effective way to deepen the understanding of the current situation of the supramolecular aggregates and it is important to understand the aggregation of asphaltene in theory and practice.Petroporphyrins is an important component of petroleum.The aggregation between petroporphyrins and polycyclic aromatic hydrocarbons is generally considered as an important part of the mechanism of asphaltene association.Phthalocyanine and porphyrin are very similar in structure.Therefore,novel tetra-[1H-benzo?d?imidazol-2-thio]phthalocyanine?TBIT-Pc?and tetra-[1H-benzo?d?thiazol-2-thio]phthalocyanine?TBTT-Pc?have been designed,and the mode and process of aggregation have been studied.4-Nitrophthalonitrile,2-mercaptobenzimidazole and 2-mercaptobenzothiazole were used as raw materials to synthesize substituted phthalocyanine compounds.The products with high purity were obtained by column chromatography.The synthesized compounds were characterized by elemental analysis,¹H NMR,MALDI-TOF MS,FT-IR and UV-vis absorption spectra.TBIT-Pc and TBTT-Pc showed good solubility in DMSO,DMF and THF.The self-assembling properties of TBIT-Pc and TBTT-Pc were comparatively investigated by means of absorption and fluorescence spectroscopies,transmission electron microscopy?TEM?.TBIT-Pc and TBTT-Pc were stable in DMF.TBTT-Pc showed monomeric behavior in DMSO.Mainly depending on the intermolecular hydrogen bonding between-NH in the substitutes,TBIT-Pc exhibited the tendency of forming“head-to-tail”J-aggregates in DMSO,and the extent of H-aggregation in DMSO/water was increased compared to TBTT-Pc.The morphlogy of J-aggregates and H-aggregates of TBIT-Pc and TBTT-Pc was spherical nanoparticles and dendritic nanostructure.H-bond,?-?interaction may be the main driving force for the formation of aggregates.The role of?-?stacking and hydrogen bond played in the aggregation of substituted phthalocyanines could provide help for the understanding of the situation of asphaltene at the molecular level.On the basis of the research contents above,tetra-?3-phenyl-2-propylene-1-oxyl?phthalocyanine?TPPO-Pc?with no group on substituents to form hydrogen bonds has been designed.4-Nitrophthalonitrile and cinnamic alcohol were used as materials to synthesize tetra-?3-phenyl-2-propylene-1-oxyl?phthalocyanine.TPPO-Pc was characterized by ¹H NMR,MALDI-TOF MS,FT-TR and UV-vis absorption spectra.The self-assembled behavior in organic solvents of phthalocyanine derivative was investigated by absorption and fluorescence spectroscopy,TEM.TPPO-Pc was stable in most organic solvents,such as DMF,DMSO,acetone and toluene.However,the TPPO-Pc exhibited the tendency of forming“face-to-face”stacking mode aggregates?H-aggregates?in acetone/water,DMSO/water and DMF/water mixed solutions.Different size dendritic nanostructure of TPPO-Pc was formed in acetone/water and DMF/water.However,core-shell nanospheres of TPPO-Pc were formed in the DMSO/water mixed solutions.H-bond,?-?interaction may be the main driving force for the formation of H-aggregates.Tetra-?3-phenyl-2-propylene-1-oxyl?phthalocyanine with the substituents containing no active hydrogen atoms showed similar aggregation with tetra-[1H-benzo?d?imidazol-2-thio]phthalocyanine,and H-aggregates could be only formed in solution.H-bond in the ring plane and?-?interaction may be the main driving force in the H-aggregation of tetra-?3-phenyl-2-propylene-1-oxyl?phthalocyanine.It was indicated that the similar structure would have a similar aggregation pattern in the formation of the supramolecular structure.This research would provide help for the study of the accosiation of petroleum fractions.In order to study the influence of the strength of the intermolecular hydrogen bond formed on the substituted group of phthalocyanines,tetra-?1-amino-1-carboxyl-2-thio?phthalocyanine with multiple groups on the substituents to form hydrogen bonds has been designed.4-?1-amino-1-carboxyl-2-thio?phthalonitrile was synthesized by the reaction of4-nitrophthalonitrile and cysteine,then the tetra-?1-amino-1-carboxyl-2-thio?phthalocyanine with many carboxyl and amino group was synthesized via DBU as catalyst.Tetra-?1-amino-1-carboxyl-2-thio?phthalocyanine was characterized by FT-IR and MALDI-TOF MS.Tetra-?1-amino-1-carboxyl-2-thio?phthalocyanine was soluble in DMF,DMSO and water.The aggregation behavior of phthalocyanine derivative in solution was investigated by UV-vis absorption spectra.Tetra-?1-amino-1-carboxyl-2-thio?phthalocyanine was presented in the form of monomer in DMSO and water,but it was aggregated in DMSO/water mixed solution and J-aggregates were formed.J-aggregates were only formed in the solution of substituted phthalocyanine when the group on the substituents formed a number of cooperative hydrogen bonds.The hydrogen bond formed by–COOH and-NH₂ on the substituents may be the main driving force for the J-aggregation of tetra-?1-amino-1-carboxyl-2-thio?phthalocyanine.For the study of the aggregation of compounds not containing macrocyclic but still containing the active hydrogenatoms substituent aggregation in solution,2-?5-dibenzothiophenecarbonyl?benzoic acid was synthesized on the basis of dibenzothiophene,phthalic anhydride and alcohol compounds.For the comparative research,three kinds of esters of 2-?5-dibenzothiophenecarbonyl?benzoic acid were synthesized.The compounds were characterized by elemental analysis,FT-IR,¹H NMR and MALDI-TOF MS.The self-association behavior of these dibenzothiophene derivatives was investigated by UV-vis absorption spectra,FT-IR spectra and AFM.It was found that2-?5-dibenzothiophenecarbonyl?benzoic acid exhibited strong aggragation trend in CH₂Cl₂solution,while the esterification product of 2-?5-dibenzothiophenecarbonyl?benzoic acid showed no aggregation.Hydrogen bonding of carboxyl was confirmed to be the main driving force for the formation of carboxylic acid aggregates.And the aggregation induced by?-?stacking interactions of smaller aromatic ring systems in the four compounds was not obvious.To study the effects of the compounds with aromatic ring,heteroatom and alkyl chain on the aggregation of resins and asphaltenes in solutions,the influnce of model compounds on the aggregation of resins and asphaltenes was investigated by means of UV-vis absorption and fluorescence spectroscopies.The results showed that these compounds had different the influence on the aggregation of resin and asphaltene in THF solution.These compounds containing aromatic ring,hetero atom and alkyl chain which showed aggregation could promote the aggregation of resin and asphaltene.