Alcohols Fischer-Tropsch process

Sasol Fischer-Tropsch Process. 1-Propanol is one of the products from Sasol s Fischer-Tropsch process (7). Coal (qv) is gasified ia Lurgi reactors to produce synthesis gas (H2/CO). After separation from gas Hquids and purification, the synthesis gas is fed iato the Sasol Synthol plant where it is entrained with a powdered iron-based catalyst within the fluid-bed reactors. The exothermic Fischer-Tropsch reaction produces a mixture of hydrocarbons (qv) and oxygenates. The condensation products from the process consist of hydrocarbon Hquids and an aqueous stream that contains a mixture of ketones (qv) and alcohols. The ketones and alcohols are recovered and most of the alcohols are used for the blending of high octane gasoline. Some of the alcohol streams are further purified by distillation to yield pure 1-propanol and ethanol ia a multiunit plant, which has a total capacity of 25,000-30,000 t/yr (see Coal conversion processes, gasification). 

Development of SASOL. Over 70% of South Africa s needs for transportation fuels are being suppHed by iadirect Hquefaction of coal. The medium pressure Fischer-Tropsch process was put iato operation at Sasolburgh, South Africa ia 1955 (47). An overall flow schematic for SASOL I is shown ia Figure 12. The product slate from this faciUty is amazingly complex. Materials ranging from hydrocarbons through oxygenates, alcohols, and acids are all produced. 

As a constituent of synthesis gas, hydrogen is a precursor for ammonia, methanol, Oxo alcohols, and hydrocarbons from Fischer Tropsch processes. The direct use of hydrogen as a clean fuel for automobiles and buses is currently being evaluated compared to fuel cell vehicles that use hydrocarbon fuels which are converted through on-board reformers to a hydrogen-rich gas. Direct use of H2 provides greater efficiency and environmental benefits. ... 

In the Fischer-Tropsch process, carbon monoxide reacts with hydrogen in the presence of a solid catalyst, with the formation of a mixture of hydrocarbons. The composition of the product varies considerably with the catalyst and the operating conditions. The mixture may include (in addition to hydrocarbons) alcohols, aldehydes, ketones, and acids. 

Synol A version of the Fischer-Tropsch process developed in Germany during World War II. It used a different catalyst and produced a larger fraction of alcohols and olefins. 

The oxo reaction (31) is carried out in the liquid phase at high pressure using a cobalt catalyst. A mixture of aldehyde isomers is always produced, each isomer being one carbon number higher than the starting olefin. As a group the oxygenated products of the hydrocarbon synthesis (Fischer-Tropsch) process and the oxo process are primary compounds and thus (except, of course, the methyl and ethyl derivatives) differ fundamentally from the products based on alcohols made by the hydration of olefins, which are always secondary or tertiary in structure. 

In the production of paraffins, the mixture of carbon monoxide and hydrogen is enriched with hydrogen from the water-gas catalytic (Bosch) process, i.e., shift reaction (Fig. 1), and passed over a cobalt-thoria catalyst to form straight chain (linear) paraffins, olefins, and alcohols (Fischer-Tropsch synthesis) ... 

The Fischer-Tropsch process Reaction of carbon monoxide with hydro- 9,16.28, 32,44, gen in the presence of a solid catalyst to produce a mixture of 58,64.65,66. hydrocarbons, alcohols, aldehydes, ketones, and acids depending upon 67, 68. 69,85, operating conditions and the nature of the caialyst 105... 

The products of this reaction, an equimolar mixture of H2 and CO (called synthesis gas or syn gas some CO2 may be produced as a by-product), can be used with metallic heterogeneous catalysts in the synthesis of a variety of useful organic products. For example, the Fischer-Tropsch process, developed by German chemists in the early 1900s, uses transition metal catalysts to prepare hydrocarbons, alcohols, alkenes, and... 

An interesting sequel to the Fischer-Tropsch synthesis is the so-called 0X0 reaction. Olefines derived from the Fischer-Tropsch process will react with carbon monoxide and hydrogen in the presence of cobalt carbonyl at temperatures of 110° to 150°C, under pressures of 150 to 200 atmospheres, to yield aldehydes. These can either be reduced to alcohols or oxidized to fatty acids, and they are derived from the petroleum industry... 

Hydrogenation of carbon oxides with iron, cobalt, or nickel catalysts (Fischer-Tropsch process). Hydrocarbons are the main products Recovery and separation of oxygenated products obtained from CO and H2 Partial oxidation of nonaromatic hydrocarbon mixtures, e.g., petroleum, paraffins, and natural gas, to produce a mixture of products, such as esters, acids, aldehydes, ketones, and alcohols. This also includes higher fatty acids from petroleum and patents on formaldehyde production... 

The most highly developed commercial technology for converting coal-derived syngas into a light syncrude is a hybrid gasification-liquefaction process known as Fischer-Tropsch technology. The Fischer-Tropsch process catalyti-cally converts synthesis gas into a variety of hydrocarbons, alcohol, ketone... 

The isoparaffin synthesis studied at the Kaiser Wilhelm Institut fur Kohlenforschung (37, 67, 68, 69) is more closely related to the synthesis of the higher molecular weight alcohols using difficultly reducible oxides plus alkali as catalysts, than to the Fischer-Tropsch process. Thoria, zinc oxide. 

We have studied the synthesis of fatty acids by the closed Fischer-Tropsch process, using various carbonates as promoters and meteoritic iron as catalyst. The conditions used were D2/CO mole ratio = 1 1, temperature == 400°C, and time = 24-48 hr. Sodium, calcium, magnesium, potassium, and rubidium carbonates were tested as promoters but only potassium carbonate and rubidium carbonate produced fatty acids. These compounds are normal saturated fatty adds ranging from C5 to Cis, showing a unimodal Gaussian distribution without predominance of odd over even carbon-numbered aliphatic chains. The yields in general exceed the yields of aliphatic hydrocarbons obtained under the same conditions. The fatty acids may be derived from aldehydes and alcohols produced under the influence of the promoter and subsequently oxidized to the acids. 

Fatty acids in relatively high yields (usually in excess of the yields of aliphatic hydrocarbons) can be produced in a closed-system Fischer-Tropsch process using meteoritic iron as a catalyst, provided potassium carbonate or rubidium carbonate is used as a promoter. Aldehydes and alcohols or oxygenated intermediate complexes attached to the catalyst may be the source of the fatty acids. 

In 1923 two German scientists, Franz Fischer (1877-1947) and Hans Tropsch (1889-1935) developed a process whereby coke exposed to steam in the presence of catalysts forms a variety of organic compounds (hydrocarbons, aldehydes, ketones, alcohols) depending upon the catalyst and other specific conditions. Around this time, Alwin Mittasch (1869-1953), who developed the catalyst for the Haber-Bosch Process (chapter 1), introduced a related reaction in which carbon monoxide and hydrogen are combined in the presence of chromium oxide and zinc oxide (and similar combinations) to form methanol. The Fischer-Tropsch process played an important role in the synthesis of fuels... 

Since the 1980s, SSITKA has been widely used to understand the formation mechanism of methane as the first paraffin in the chain. The study of the dynamics of the entire complex of reactions involved in the Fischer-Tropsch process became possible only after the development of the GC-MS technique with high resolution time. A review of field suggests that the cycle of papers by van Dijk et al. [18-21] describes the results that were obtained using the full potential of the SSITKA technique. First, a comparison of C, O, and H labeling on different Co-based catalyst formulations and in different conditions was made. For the first time, a substantial part of the product spectrum (both hydrocarbons and alcohols) was included in the isotopic transient analysis. After the qualitative interpretation of the experimental data, extensive mathematical modeling was performed for the identification and discrimination of reaction mechanisms. 

The Fischer-Tropsch process was developed by F. Fischer and H. Tropsch in 1921 to produce clean alternative fuel from coal, natural gas, and low-grade refinery products for use in automobile and diesel engines. The process entails the synthesis of hydrocarbons and other aliphatic compounds, such as alcohols, from a mixture of hydrogen and carbon monoxide (synthesis gas, or syngas). The following equation illustrates the chemical reactions involved in the process ... 

Further CO hydrogenation (Fischer-Tropsch process) gives (-CH2-)n and wata-, but olefins and alcohols are also produced in Iowct amounts than paraffins. 

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