2-Ethylhexanol manufacture

Ethylhexanol Manufacture Using A Rhodium Catalyst For The Oxo Reaction... 

Figure 3. 2-Ethylhexanol manufacture using a rhodium catalyst for the oxo reaction (3,5,)...

On the basis of the data available so far it looks as if this process is well suited for the single-step production of alcohols but less suited if aldehydes are the desired reaction products, which is the case in the 2-ethylhexanol manufacture and similar aldol routes, in the manufacture of carboxylic acids and some other operations (as to the possibility of making a certain amount of aldol product along with the lower molecular alcohols in the Shell process, see chapter 7). 

The important solvent and plasticizer intermediate, 2-ethylhexanol, is manufactured from -butyraldehyde by aldol addition in an alkaline medium at 80-130°C and 300-1010 kPa (3-10 atm). 

Aldehydes fiad the most widespread use as chemical iatermediates. The production of acetaldehyde, propionaldehyde, and butyraldehyde as precursors of the corresponding alcohols and acids are examples. The aldehydes of low molecular weight are also condensed in an aldol reaction to form derivatives which are important intermediates for the plasticizer industry (see Plasticizers). As mentioned earlier, 2-ethylhexanol, produced from butyraldehyde, is used in the manufacture of di(2-ethylhexyl) phthalate [117-87-7]. Aldehydes are also used as intermediates for the manufacture of solvents (alcohols and ethers), resins, and dyes. Isobutyraldehyde is used as an intermediate for production of primary solvents and mbber antioxidants (see Antioxidaisits). Fatty aldehydes Cg—used in nearly all perfume types and aromas (see Perfumes). Polymers and copolymers of aldehydes exist and are of commercial significance. 

Uses Manufacture of acetic acid, acetic anhydride, aldol, aniline dyes, 1-butanol, 1,3-butylene glycol, cellulose acetate, chloral, 2-ethylhexanol, paraldehyde, pentaerythritol, peracetic acid, pyridine derivatives, terephthalic acid, trimethylolpropane, flavors, perfumes, plastics, synthetic rubbers, disinfectants, drugs, explosives, antioxidants, yeast silvering mirrors hardening gelatin fibers. 

Another oxo plant, now being constructed, will make butyl compounds (88). These may be the source of butyl alcohol, butyl acetate, butyric acid for the manufacture of cellulose acetate butyrate and other products, butyraldehyde for polyvinyl butyral, and the eight-carbon compounds including 2-ethylhexanol. All these will add to the present production of the same compounds made by the older methods from acetaldehyde via aldol condensation. 

Di-2-EthylhexylPhthalate. In Western Europe, di-2-ethylhexyl phthalate [117-81-7] (DEHP), also known as dioctyl phthalate (DOP), accounts for about 50% of all plasticizer usage and as such is generally considered as the industry standard. The reason for this is that it is in the mid-range of plasticizer properties. DEHP (or DOP) is the phthalate ester of 2-ethylhexanol, which is normally manufactured by the dimerization of butyraldehyde (eq. 2), the butyraldehyde itself being synthesized from propylene (see Butyraldehydes). 

Ethanol s use as a chemical intermediate (Table 8) suffered considerably from its replacement in the production of acetaldehyde, butyraldehyde, acetic acid, and ethylhexanol. The switch from the ethanol route to those products has depressed demand for ethanol by more than 300 x 106 L (80 x 106 gal) since 1970. This decrease reflects newer technologies for the manufacture of acetaldehyde and acetic acid, which is the largest use for acetaldehyde, by direct routes using ethylene, butane (173), and methanol. Oxo processes (qv) such as Union Carbide s Low Pressure Oxo process for the production of butanol and ethylhexanol have totally replaced the processes based on acetaldehyde. For example, U.S. consumption of ethanol for acetaldehyde manufacture declined steadily from 50% in 1962 to 37% in 1964 and none in 1990. Butadiene was made from ethanol on a large scale during Wodd War II, but this route is no longer competitive with butadiene derived from petroleum operations. 

Phthalic anhydride is used for the manufacture of plasticizers, such as dioctyl phthalate, unsaturated polyester resins, and alkyd resins. Phthalic anhydride reacts with alcohols such as 2-ethylhexanol, and the products are often liquids that, when added to plastics, impart flexibility without adversely affecting the strength of the plastic. Most of these plasticizers are used for poly(vinyl chloride) flexibility. Dioctyl phthalate is a common plasticizer. 

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. 

Manufacture of /i-Butanol and 2-Ethylhexanol by the Rhodium Oxo Process and Applications of the Alcohols... 

The production of 2-ethylhexanol from propylene by the rhodium catalyzed, low pressure oxo process is accomplished in three chemical steps. The first step of the process (described in section on n-butanol manufacture) converts propylene to normal butyraldehyde by hydroformylation in the presence of a rhodium catalyst. In a second step, the normal aldehyde is aldoled to form 2-ethylhexena1. 2-Ethylhexenal is then hydrogenated to 2-ethylhexanol and refined in the third and final step(see Figure 3). 

The key industrial applications and markets for normal and isobutanol and 2-ethylhexanol are discussed. As will be noted, the C4 oxo alcohols find use primarily within the coatings industry, either as solvents, per se, or as intermediates to manufacture solvents or protective coatings chemicals. Applications for 2-ethylhexanol, while numerous and varied, are basically oriented toward the manufacture of plasticizers for polyvinyl chloride. Total U.S. consumption of these alcohols in 1979 was approximately 1.3 billion pounds -730 million pounds of n-butanol, 190 million pounds of isobutanol, and 380 million pounds of 2-ethylhexanol. The consumption pattern is summarized in Table II and described in the following sections ... 

Isobutanol use in the manufacture of zinc dialkyl dithiophosphates (ZDDP), anti-wear lube oil additives, represented 13 percent of domestic consumption. Other alcohols used in this application include methylamyl alcohol, primary amyl,alcohol, n-butanol, 2-ethylhexanol and isooctanol. 

Ethylhexanol. Use of 2-ethylhexanol in the manufacture of PVC plasticizers, most notably DOP (di-2-ethylhexyl phthalate), has historically accounted for over 70 percent of U.S. demand for this alcohol. DOP has been the most widely used general purpose PVC plasticizer for close to half a century and is considered the "workhorse" of the industry. The material is used in a wide variety of PVC resin applications including flooring, wire and cable, packaging and coated fabrics. In the past, DOP has represented the industry cost/ performance standard against which all competing plasticizers were measured. 

The alcohol also finds use in the manufacture of lube and fuel oil additives and synthetic lubricants (about 6 percent of domestic consumption). The zinc dialkyl dithiophosphate anti-wear additive based on 2-ethylhexanol provides ideal compatability, oil solubility, and high temperature stability in many lube oils for both spark ignition and diesel engines. 

About 4 percent of 2-ethylhexanol domestic demand is consumed in the manufacture of di-2-ethylhexyl sulfosuccinate -a general purpose anionic surfactant used in textile processing. 

While n-butanol from the oxo process did not become a major intermediate for PVC plasticizers, the development was nonetheless a breakthrough of far-reaching significance. The precursor of n-butanol in the oxo process is n-butyraldehyde. This made possible the manufacture of 2-ethylhexanol by "single aldol" at lower cost than the "double aldol" route via acetaldehyde. 

The next breakthrough of importance for future 2-ethylhexa-nol plants occurred in the mid seventies. This was the development of the rhodium-catalyzed oxo process by Union Carbide, Davy Powergas and Johnson-Matthey (See Chapter 6). This process not only operates at lower temperatures and pressures than the conventional cobalt-catalyzed process but also gives a far lower yield of the less valuable isobutyraldehyde by-product. The net result is improved economics vs. the cobalt process for n-butyr-aldehyde - the intermediate for 2-ethylhexanol. Although outside the U.S. this new technology has already been licensed and plants are now operating(16), no new plants were constructed in the U.S. specifically for 2EH manufacture in the seventies. However,... 

The hydroformylation of alkenes to give linear aldehydes constitutes the most important homogeneously catalyzed process in industry today [51]. The hydroformylation of propene is especially important for the production of n-bu-tyraldehyde, which is used as a starting material for the manufacture of butanol and 2-ethylhexanol. Catalysts based on cobalt and rhodium have been the most intensively studied for the hydroformylation of alkenes, because they are industrially important catalysts. While ruthenium complexes have also been reported to be active catalysts, ruthenium offers few advantages over cobalt or... 

Trialkyl phosphates are manufactured by reacting phosphorus(V) oxychloride with excess alcohol, in particular ethanol, butanol, isobutanol and 2-ethylhexanol ... 

The future of the commercial acetaldehyde processes mainly depends on the availability of cheap ethylene. Acetaldehyde has been replaced as a precursor for 2-ethylhexanol ( aldol route ) or acetic acid (via oxidation cf. Sections 2.1.2.1 and 2.4.4). New processes for the manufacture of acetic acid are the Monsanto process (carbonylation of methanol, cf. Section 2.1.2.1), the Showa Denko one-step gas-phase oxidation of ethylene with a Pd-heteropolyacid catalyst [75, 76], and Wacker butene oxidation [77]. Other outlets for acetaldehyde such as pentaerythritol and pyridines cannot fill the large world production capacities. Only the present low price of ethylene keeps the Wacker process still attractive. 

Butanal is used in the manufacture of rubber accelerators, synthetic resins, solvents, and plasticizers. -Butyraldehyde is used as an intermediate in the manufacturing of plasticizers, alcohols, solvents, and polymers (such as 2-ethylhexanol, -butanol, trim-ethylolpropane, -butyric acid, polyvinyl butyral, methyl amyl ketone). It is also used as an intermediate to make pharmaceuticals, agrochemicals, antioxidants, rubber accelerators, textile auxiliaries, perfumery, and flavors. It has no therapeutic use at the present time. 

Use Manufacture of acetic acid and acetic anhydride, n-butanol, 2-ethylhexanol, peracetic acid, aldol, pentaerythritol, pyridines, chloral, 1,3-butylene glycol, and trimethylolpropane synthetic flavors. 

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