Catalyst current production processes

The previous referred inconveniences have prompted an increasing interest in the development of alternative, essentially neutral and more environmental-friendly catalysts to promote the rearrangement of O-unsubstituted oximes. The development of highly efficient and selective transformations and also of processes for catalyst recovery and its reuse are the aim of some of the more recent studies. Much of this work is being done in industry to improve current production processes and is the subject of new patent applications. During the last two decades environment concerns have led to the development of green, simple and cost-effective catalytic systems for the Beckmann rearrangement. 

ANL s novel process uses pervaporation membranes and catalysts. In the process, ammonium lactate is thermally and catalytically cracked to produce the acid, which with the addition of alcohol is converted to the ester. The selective membranes pass the ammonia and water with high efficiency while retaining the alcohol, acid, and ester. The ammonia is recovered and reused in the fermentation to make ammonium lactate, eliminating the formation of waste salt. The innovation overcomes major technical hurdles that had made current production processes for lactate esters technically and economically noncompetitive. The iimovation will enable the replacement of toxic solvents widely used by industry and consumers, expand the use of renewable carbohydrate feedstocks, and reduce pollution and emissions. 

Both new catalysts and new processes need to be developed for a complete exploitation of the potential of CO2 use [41]. The key motivation to producing chemicals from CO2 is that CO2 can lead to totally new polymeric materials and also new routes to existing chemical intermediates and products could be more efficient and economical than current methods. As a case in point, the conventional method for methanol production is based on fossil feedstock and the production of dimethyl carbonate (DMC) involves the use of toxic phosgene or CO. A proposed alternative production process involves the use of CO2 as a raw material (Figure 7.1)... 

The potential importance of homogeneous catalytic reactions in synthesis gas transformations (i.e., hydrogenation of carbon monoxide) has been widely recognized in recent years. In the first place, such systems could provide structural and mechanistic models for the currently more important, but more difficult to study, heterogeneous catalysts. Secondly, product selectivity is generally more readily achievable with homogeneous catalysts, and this would be an obviously desirable feature in an efficient process converting synthesis gas to useful chemicals and fuels. 

This compound is notorious as a hard sulfide that cannot be removed from petroleum by current hydrodesulfurization processing. Oxidation by tert-butyl hydroperoxide occurs readily when 1 is used as the catalyst. After trying several combinations, this was the most effective 0.5 mmol of DMDBT, 1.75 mmol B OOH, and 0.05 mol% of 1 were placed in refluxing toluene (384 K). A quantitative yield of the dioxide was obtained in 2h. The oxidation product is insoluble in toluene and can readily be removed by filtration (42). 

The present review summarizes contemporary views of the problems, achievements, and prospects involved in the deep desulfurization of gas oils, including identification and reactivity of sulfur species in the feed, the reaction pathways and mechanisms, activity and selectivity of the conventional catalysts, and concerns of fluorescence color production. Process schemes and guidelines for the development of the next-generation catalysts for improved deep desulfurization technology based on these discussions are also proposed. The structure and nature of the active sites of current catalysts will not be extensively covered in this review, because several excellent reviews have been published on these subjects within the past two years (1-3). 

Methanol production today is not a sustainable process but is part of a petrochemical route for conversion of fossil carbon into chemicals and fuels (see Section 5.3.3). It has to be emphasized that a one-to-one upscaling of existing industrial methanol synthesis capacities for fuel production is not useful. This is mainly because the current industrial process has not been developed and optimized under the boundary conditions of conversion of anthropogenic C02, but rather for synthesis gas feeds derived from fossil sources such as natural gas or coal. The switch to an efficient large-scale methanol synthesis with a neutral C02 footprint is still a major scientific and engineering challenge, and further research and catalyst and process optimization is urgently needed to realize the idea of a sustainable methanol economy. ... 

Chlorobenzenes. Of the 12 different chlorobenzenes that can result from the chlorination of benzene, three are of most commercial importance monochlorobenzene (MCB), o-dichlorobenzene (ODCB), and /7-dichlorobenzene (PDCB). Chlorination of benzene can be done either batchwise or continuously in the presence of a catalyst such as ferric chloride, aluminum chloride, or stannic chloride. It is usually run as a three-product process the current product distribution is about 52 percent to MCB, 17 percent ODCB and 31 percent PDCB. The pure compounds are separated from the crude by distillation and crystallization. 

An important current industrial process based on N-C cleavage using hydrogen peroxide is the manufacture of iV-phosphonomethylglycine (systemic herbicide, glyphosate) from AT-phosphonomethyl imido diacetic acid via the N-oxide (Figure 3.88).347 //-Oxidation is catalysed by molybdate or tungstate and the intermediate formed can be decomposed with a second catalyst such as iron(II) to form the product.348... 

There is a major economic incentive to extend the current HC processes to enable heavier feedstocks to be converted to lighter, higher-value transportation fuels. Studies by Idemitsu indicate that iron-modified zeolite catalysts significantly enhance conversion when heavy oils such as long residue are hydroprocessed (65). Nevertheless, major technical barriers exist which make high conversions and product selectivities difficult to achieve with truly heavy feeds (end boiling points beyond 620 °C) - these include ... 

Catalysts currently employed in process development units for coal liquefaction are hydroprocessing catalysts developed for petroleum refining (5l6). They are composed of combinations of Mo or W with Co, Ni or other promoters dispersed on alumina or silica-alumina supports. When used in liquefaction, these catalysts deactivate rapidly f6-9i causing decreases in product yield and quality and problems with process operability. Thus the... 

This was the first application of a fluidized bed to a process that necessitates removal of large heat of reacticm (about 450 kcal/gm-mole naphthalene) and high yield. The fluidized process surpassed fixed-bed processes in safe operation at high ccmcentration, in yield, in reduced pollution, and in plant cost—probably because the reacticm was rather simple and the products were stable. Fluid bed catalysts currently in use... 

A less well-known example, but which further exemplifies the potential of solid acid catalysts in improving process sustainability, is the industrial production of methylenedianiline (MDA), used as an intermediate for the production of high-tech polyurethanes. Figure 2.31a shows the industrial process currently used. It is a... 

---