The catalytic aquathermolysis becomes an important area for investigation to solve some of the problems during exploration of heavy crude oil. It has been reported in 1982 by Hyne et al. that metals can accelerate the aquathermolysis and thereafter the uses of several catalysts on this reaction have been studied. It is believed that superheated water passes heat to the hydrocarbon, and some asphaltene molecules are broken down by thermal heat to small molecules. Hence the viscosity as well as flow properties of heavy oil are improved. Moreover, the added heat provides driving force or pressure so that the viscous oils can flow easily and increases the oil production. When the catalyst is present on this reaction system, the viscosity is reduced very deeply. In general the catalysts employed for aquathermolysis are mineral, water-soluble, oil soluble, and dispersed catalyst. The viscosity reduction with these catalysts is in the order of mineral < water-soluble catalyst < oil-soluble catalyst < dispersed catalyst. It has also been found that during aquathermolysis, the saturates and aromatics increase while the amount of asphaltene and resin decreases. The use of different hydrogen donors on aquathermolysis also improves the quality of the heavy crude oil. The most commonly used hydrogen donor is tetralin. Moreover, when tetralin is used with a catalyst, the viscosity is also reduced more effectively. The use of catalysts in the real oil field indicates that the catalysts can substantially reduce viscosity and hence the catalytic aquathermolysis process can be used successfully for exploration of heavy crude oils. However, the oil soluble and dispersed catalysts are slightly more active than the water-soluble catalyst. The cost of the former two types of catalysts may be higher than the preparation cost of simple water-soluble catalysts. Therefore, more research is needed so that the catalysts can be used for this process more economically. Another problem is the efficiency of these catalysts in the oil field. The activity of the catalysts depends on the homogeneity of the temperature in the oil floor. When the superheated water is injected into the oil reservoir, the oil surface temperature is high. However, temperature is gradually lower on the depth of the oil floor, and hence the catalyst loses its activity. So, further investigation is also necessary to address this aspect.

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An incisively designed notable aggregation-induced emission enhancement (AIEE) active fluorescence probe, 1-(2hydroxynaphthylmethylene)-2-(3-methoxy-2-hydroxybenzylidene) hydrazine (L), was synthesized via straightforward reaction from inexpensive reagents. It exhibited rapid response, superb selectivity, and swift sensitivity toward Zn 2+ based on its promising CHEF/AIEE feature. L not only can sense Zn 2+ through sharp colorimetric and selective turn-on fluorescence responses in DMF/H 2 O (9:1, v/v) medium, but also can distinguish between its significant AIEE activity in high water ratio and Zn 2+ triggered AIEE activity through individual emission signals. Intriguingly, the AIEE properties of L may improve its impact. The molecules of L are aggregated into ordered one-dimensional rod-shaped microcrystals that show an obvious optical waveguide effect. Job's plot from UV−vis absorption revealed the formation of L-Zn 2+ complex with 1:1 stoichiometry. When bound with Zn 2+ in 1:1 mode, enhanced turn-on emission was observed via chelation enhanced fluorescence through sensor complex (L-Zn) formation and excess addition of Zn 2+ , a vivid enhancement of fluorescence intensity over manifold through aggregate formation was observed. The entire process takes ∼5 s, i.e., faster response time. The probe can detect Zn 2+ as low as 1.1 × 10 −7 M. The AIEE mechanism of L and Zn 2+ triggered AIEE mechanism were well established from fluorescence anisotropy, DLS, SEM, optical fluorescence microscope, time-resolved photoluminescence, and fluorescence reversibility study by adding Zn 2+ and EDTA sequentially. Furthermore, the proposed analytical system with clear AIEE mechanism demonstrates a potential outlook for the on-site practical applications.

Almost complete removal of 4,6-dimethyl dibenzothiophene (4,6-DMDBT) will perhaps be inevitable for reducing the sulfur content of diesel to a level of 50 wppm and lower. The hydrodesulfurization (HDS) of 4,6-DMDBT does not tend to occur through direct desulfurization, a pathway typically followed by reactive sulfur compounds over conventional CoMo/Al2O3 catalysts. Its reactivity can be enhanced either by increasing the rate of direct desulfurization or by transforming it to a more activated molecule through hydrogenation, isomerization, demethylation, and C−C bond scission. Attempts have been made to develop better catalysts using these concepts. Different additives such as phosphorus, fluorine, and lanthanum have been added to the alumina support for developing the required catalytic properties. Various other supports such as zeolite, zirconia, titania, etc., by themselves or in admixtures with alumina have also been used to improve the HDS activities of the catalysts. This article reviews the results of recent studies conducted in this area and summarizes the advances that have taken place in this direction.

A pyrene based fluorescent probe, 3-methoxy-2-((pyren-2yl-imino)methyl)phenol (HL), was synthesized via simple one-pot reaction from inexpensive reagents. It exhibited high sensitivity and selectivity toward Al(3+) over other relevant metal ions and also displayed novel aggregation-induced emission enhancement (AIEE) characteristics in its aggregate/solid state. When bound with Al(3+) in 1:1 mode, a significant fluorescence enhancement with a turn-on ratio of over ∼200-fold was triggered via chelation-enhanced fluorescence through sensor complex (Al-L) formation, and amusingly excess addition of Al(3+), dramatic enhancement of fluorescence intensity over manifold through aggregate formation was observed. The 1:1 stoichiometry of the sensor complex (Al-L) was calculated from Job's plot based on UV-vis absorption titration. In addition, the binding site of sensor complex (Al-L) was well-established from the (1)H NMR titrations and also supported by the fluorescence reversibility by adding Al(3+) and EDTA sequentially. Intriguingly, the AIEE properties of HL may improve its impact and studied in CH3CN-H2O mixtures at high water content. To gain insight into the AIEE mechanism of the HL, the size and growth process of particles in different volume percentage of water and acetonitrile mixture were studied using time-resolved photoluminescence, dynamic light scattering, optical microscope, and scanning electron microscope. The molecules of HL are aggregated into ordered one-dimensional rod-shaped microcrystals that show obvious optical waveguide effect.

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