Monsanto technology

In 1986, BP Chemicals became the owners of the Monsanto technology. They subsequently also developed their own Cativa process, aimounced in 1996, carbonylation of MeOH to AcOH catalysed by Ir and Mel and promoted with specific metal iodides [8]. As with the improvements in the original Monsanto Rh process, Cativa had benefits such as improved catalyst stability and more favorable operating conditions [9]. 

As seen from the above, conventional uses of methanol cover a wide range of products which in turn find application in a very broad cross-section of industrial and consumer goods. New end uses have continued to develop and spur the growth of methanol production. One such development is the Monsanto low pressure process that carbonylates methanol to acetic acid (6). Essentially all new acetic acid capacity now being installed is based on Monsanto technology. By 1981, eleven plants converting methanol to acetic acid are scheduled to be on stream. At capacity they will consume over 300 million gallons of methanol. 

The use of the HEA Column plus the DCN Reactor in series (see Figure 9.8) allows the optimization of the operating conditions and the operating cost. The HEA Column removes the majority of the NOx and stabilizes the NOx content in the tail gas. The DCN reactor destroys the remaining NOx as required to meet the emission limits. A comparison of the operating conditions for the Monsanto technology is given in Table 9.7". 

Monsanto Enviro-Chem offers NOx abatement technology that is licensed from Rhodia of France. It includes a high efficiency absorption (HEA) section for extended absorption and a catalytic reduction section (SCR) for catalytic destruction of NOx (i.e., the DCN technology).99 Additional process details are given in Reference 99. The operating conditions for the steps in the Monsanto technology are compared in Table 22.19. 

In the 1990s, BP re-examined the iridium-catalyzed methanol carbonylation chemistry first discovered by Paulik and Roth and later defined in more detail by Forster [20]. The thrust of this research was to identify an improved methanol carbonylation process using Ir as an alternative to Rh. This re-examination by BP led to the development of a low-water iridium-catalyzed process called Cativa [20]. Several advantages were identified in this process over the Rh-catalyzed high-water Monsanto technology. In particular, the Ir catalyst provides high carbonylation rates at low water concentrations with excellent catalyst stability (less prone to precipitation). The catalyst system does not require high levels of iodide salts to stabilize the catalyst. Fewer by-products are formed, such as propionic acid and acetaldehyde condensation products which can lead to low levels of unsaturated aldehydes and heavy alkyl iodides. Also, CO efficiency is improved. 

Since the development of Cativa , BP has converted three world-scale acetic acid plants from the old Rh-based high-water Monsanto technology to the Ir-based low-water process. Significant capital and operating cost savings were achieved from the conversion of a Rh-based process to an Ir-based process. Also, the start-up in 2000 of a 500 X 10 metric ton per year acetic acid plant in Malaysia uses the Cativa process [20d]. 

The first commercial plant based on the Lummus/ Monsanto technology, which later became the Lummus/ UOP technology, was commissioned in 1972. Since that time, more than 50 projects have been licensed with more than 40 plants in commercial operation as of 2004. 

MONSANTO TECHNOLOGY LLC, US VOELKER TONI, US FILLATTI JOANNE J, US BRINGE NEAL A, US ULMASOV TIM, US... 

These two derivatives of the earlier Monsanto technology are the predominant acetic acid processes today and are equally competitive in the market place. Since the advent of the Monsanto Acetic Acid process almost all new acetic acid plants are based on methanol carbonylation and acetaldehyde oxidation has been nearly phased out as a source of acetic acid. The advances in Rh and Ir based methanol carbonylation have recently been reviewed. ... 

Metabolix (with Monsanto technology) USA 1980-ongoing n.r. PHBHV and others n.r. 

In contrast to methane conversion to C2 hydrocarbons (Section 23.2) and methanol (Section 23.3), methane conversion to acetic acid is still in its infancy. This approach is by no means competitive to the present Monsanto technology. Successful methane conversion will require novel significantiy more active catalysts. 

While in the Halcon SD process a non-noble metal halide catalyst is used for methanol carbonylation, and acetic acid is converted to methyl acetate prior to hydrogenation, the ENSOL process of Humphreys and Glasgow/ BASF utiUzes the rhodium/iodide-based Monsanto technology to produce acetic acid which is directly hydrogenated to ethanol. For the ENSOL process an overall thermal efficiency of 50% and a carbon efficiency of 74% is claimed for the conversion of natural gas into ethanol [62]. 

Roundup and Roundup Ready are registered trademarks of Monsanto Technology LLC. 

The production of acetic acid on the basis of the DMTM process with the use of carbon monoxide formed in the oxidation process for methanol carbonylation is promising primarily because it permits to reach almost a 100% selectivity of formation of liquid products in terms of carbon, i.e., eliminates one of the major shortcomings of the process. In the case of development of industrial methods for extracting CO from the recirculation gases, acetic acid can be produced directly using the known Monsanto technology of methanol carbonylation. 

In 1966, the rhodium/iodide process for the catalytic production of acetic acid was initiated at the Monsanto laboratories [86]. The first production plant based on this technology started operating in 1970 in Texas City with an initial capacity of 135000 tons per year. In 1986 BP Chemicals (British Petroleum) acquired and further developed the technology while extending it all over the world. Nowadays, the global production of acetic acid reaches 8 million tons per year and it is led by two companies, Celanese (using Monsanto technology) and BP Chemicals, with processes based on both rhodium and iridium [87]. 

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