Ziegler alcohol processes

There are four basic parts of a Ziegler alcohol process. 

Synthesis of triethylaluminum from aluminum, hydrogen, and ethylene is the first segment of a Ziegler alcohol process. It can be carried out in a single step, but normally is accomplished on a commercial scale in two stages with recycle of two-thirds of the trialkylaluminum product. 

Ethyl s version of the Ziegler alcohol process has been modified in order to control the product alcohol distribution. Whereas the Conoco ALFOL alcohol process affords the full range of alcohols, C2-C3o, in a Poisson distribution, Ethyl s product distribution can be modified, for example, as shown in Figure 3 to give carbon number distributions to fit the needs of the market. 

Ziegler Alcohol Processes. Two processes for the production of synthetic fatty alcohols are based on the work of Ziegler on organic aluminum compounds the Alfol process, developed by Conoco and Ethyl Corporation s Epal process. Fatty alcohols synthesized by these processes are structurally similar to natural fatty alcohols and are thus ideal substitutes for natural products. 

Environmental Considerations. Environmental problems in Ziegler chemistry alcohol processes are not severe. A small quantity of aluminum alkyl wastes is usually produced and represents the most significant disposal problem. It can be handled by controlled hydrolysis and separate disposal of the aqueous and organic streams. Organic by-products produced in chain growth and hydrolysis can be cleanly burned. Wastewater streams must be monitored for dissolved carbon, such as short-chain alcohols, and treated conventionally when necessary. 

Aluminum Organic Synthesis of Alcohols (Ziegler-Alfol Process)... 

Primary alcohols are produced either by the catalytic hydrogenation of methyl esters or by fatty acids derived from oils and fats, e.g., coconut oil (C12-C14) or tallow (Cl6-C18), or from synthetic sources. Alcohols manufactured from natural oils and fats and from the Ziegler-type processes produce even-numbered chain length primary alcohols. 

In order to obtain good mixing of ethene with the catalyst, the original Ziegler-Natta processes used hexane as a solvent. Although the solvent is almost completely recovered, the use of a hazardous material such as hexane detracts from the greenness of the process. Since the catalyst is highly moisture sensitive it needs to be deactivated at the end of the process by addition of water or alcohol, and this produces a small waste... 

Oleochemical alcohols are primary, even carbon-numbered structures with a high linearity (>95%), while the petrochemical derivatives can be even or odd numbered, and depending on the process, their linearity can be as high as the oleochemicals (Ziegler alcohols) or can exhibit variable branching (30% modified 0X0-60% standard OXO). 

In the higher alcohol process, the displacement is affected by oxidizing the trialkyl aluminum and then hydrolyzing, to form aluminum hydroxide and the linear alcohol. In the Ziegler process for alpha olefins, ethylene is used to displace the alpha olefin. 

A detailed discussion on surfactants from secondary alcohols which are relatively little known in the U.S. is included, together with a review of linear alcohol processes (Oxo and Ziegler) and detergent applications of the Ziegler alcohols. Also covered is a discussion of the revolutionary rhodium oxo process which has already resulted in a number of new plants—announced, under construction, or in operation, worldwide—for the manufacture of n-butanol and 2-ethylhexanol. Applications of these alcohols are also discussed. 

Several commercial processes are used to produce high-density polyethylene. All employ more moderate pressures and most also use lower temperatures than the low-density polyethylene processes. The Ziegler-developed process uses the mildest conditions, 200-400 kPa (2 atm) and 50-75°C, to polymerize a solution of ethylene in a hydrocarbon solvent using a titanium tetrachloride/aluminum alkyl-based coordination catalyst. After quenching the polymerized mixture with a simple alcohol, the catalyst residues may be removed by extraction with dilute hydrochloric acid or may be rendered inert by a proprietary additive. The product is almost insoluble in the hydrocarbon solvent, so is recovered by centrifuging and drying. The final product is extruded into uniform pellets and cooled for shipping to fabricators. 

The CONDEA group operates two different types of processes for the manufacture of alkoxide derived alumians and related products, the Ziegler-ALFOL process and CONDEA s On-Purpose Process. The Ziegler process is a co-production process of linear fatty alcohols and alumina, using aluminum organic compounds as intermediates, CONDEA s own On-Purpose technology is based on the formation of aluminum alkoxide from aluminum metal and alcohol. In both processes the formation of alumina is achieved by hydrolysis of aluminum alcoholates with water. 

An evaluation of the electronic, steric, and stereochemical factors involved in the kinetics and thermodynamics of this kind of process may be most helpful in elucidating the course of the Ziegler carbometallation process [Eq. (5)], central to the industrial production of long-chain alcohols and olefins from ethylene and to the stereoregular polymerization of a-olefms (18, 21). 

Oleochemical feedstocks and Ziegler alcohols are linear. Shell s SHOP process produces alcohols with approximately 20% predominantly methyl-branching, while other OXO-type alcohols contain approximately 40-50% predominantly methyl-branching. Alkylphe-nols and alcohols based on oligomerized alkylenes are generally highly branched. 

The fourth process used to produce phthalate alcohols is the Ziegler process and the Ziegler displacement process. In the Ziegler process straight chain even-numbered carbon alcohols are produced from ethylene. Triethylaluminum is produced from aluminum, hydrogen, and ethylene. With the addition of more... 

With the Ziegler displacement process the higher alkyl group is displaced from the chain growth product by ethylene. This yields a mixture of even-numbered linear alpha olefins with the trialkyl aluminum being recycled. The odd-numbered linear alcohols are produced through hydroformylation of the olefin and hydrogenation of the odd-numbered aldehydes. 

Commercial ethylene-propylene rubbers (EPR or EPM ) generally contain about 35 mole % propylene although rubbery properties are shown by copolymers with a propylene content ranging from 30—60 mole %. At the present time, these materials are prepared exclusively by Ziegler-type processes. Generally, true solution processes are preferred in which a soluble catalyst system is used and the polymer remains in solution rather than form a slurry. A common soluble catalyst system is based on vanadium oxychloride/aluminium trihexyl. Catalysts of this type favour the formation of amorphous atactic polymers and lead to narrower molecular weight distributions than solid catalysts. Typically, polymerization is carried out at about 40°C in a solvent such as chlorobenzene or pentane and the polymer is isolated by precipitation with an alcohol. 

The Ziegler process, based on reactions discovered in the 1950s, produces predorninandy linear, primary alcohols having an even number of carbon atoms. The process was commercialized by Continental Oil Company in the United States in 1962, by Condea Petrochemie in West Germany (a joint venture of Continental Oil Company and Deutsche Erdid, A.G.) in 1964, by Ethyl Corporation in the United States in 1965, and by the USSR in 1983. 

Eatty alcohols, prepared from fatty acids or via petrochemical processes, aldol or hydroformylation reactions, or the Ziegler process, react with ammonia or a primary or secondary amine in the presence of a catalyst to form amines (10—12). 

The principal iadustrial production route used to prepare fatty amines is the hydrogenation of nitriles, a route which has been used since the 1940s. Commercial preparation of fatty amines from fatty alcohols is a fairly new process, created around 1970, which utilizes petrochemical technology, Ziegler or Oxo processes, and feedstock. 

Alternatively, the intermediate acetaldehyde (qv) for this process was obtained from ethylene by the Wacker process (9). A small amount of -butyl alcohol is produced in the United States by the Ziegler-Natta chain growth reaction from ethylene [74-85-1] (10). 

Linear, even-numbered, primary alcohols—like the natural fatty alcohols—are produced by the aluminum organic alcohol synthesis after Ziegler, the so-called Alfol process. This alcohol synthesis proceeds in three steps ... 

The Ziegler process produces linear alcohols with an even number of carbon atoms and is based on the polymerization of ethylene under catalytic conditions, generally with triethylaluminum as in the Alfol and the Ethyl processes. The distribution of alkyl chains depends on the version of the process employed but the alcohols obtained after fractionation can be equivalent to those obtained from fats and oils or have purpose-made distributions depending on the fractionation conditions. 

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