Butyl Alcohol Route

The quest for extremely small metal oxide nanoparticles with enhanced crystallinity and good dispersibility, without the need of additional stabilizing agents, led to the discovery of lert-butanol as a novel reaction medium [65,66]. It typically offers metal oxide nanoparticles free of strongly chelating surface ligands [65]. 

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An oxirane process utilizes ethylbenzene to make the hydroperoxide, which then is used to make propylene oxide [75-56-9]. The hydroperoxide-producing reaction is similar to the first step of cumene LPO except that it is slower (2,224,316—318). In the epoxidation step, a-phenylethyl alcohol [98-85-1] is the coproduct. It is dehydrated to styrene [100-42-5]. The reported 1992 capacity for styrene by this route was 0.59 X 10 t/yr (319). The corresponding propylene oxide capacity is ca 0.33 x 10 t/yr. The total propylene oxide capacity based on hydroperoxide oxidation of propylene [115-07-1] (coproducts are /-butyl alcohol and styrene) is 1.05 x 10 t/yr (225). 

The other significant industrial route to /-butyl alcohol is the acid cataly2ed hydration of isobutylene (24), a process no longer practiced in the United States. Raffinate 1, C-4 refinery streams containing isobutylene [115-11-7], / -butenes and saturated C-4s or C-4 fluid catalytic cracker (ECC) feedstocks (23)... 

However, the 0x0 reaction starting frompropylene and proceeding via the hydrogenation of butyraldehyde, has become the more widely employed commercial route for preparing / -butanol (see BuTYL ALCOHOLS Oxo PROCESS). 

Because of limitations on the ready availability of HCN, particularly in Japan, processes involving the oxidation of C4 intermediates have been developed and are now replacing the older route developed by Crawford. One important process is based on the two-stage oxidation of isobutylene or -butyl alcohol to methacrylic acid, which is then separated and esterified Figure 15.5a). 

This method was also found to be applicable to the synthesis of 1,2-cis glycofur-anosides. 2,3,5-Tri-O-benzyl-P-ghicofuranosyl fluoride 17 was found to react with various alcohols, including sterically hindered t-butyl alcohol, in the presence of SnCl2-TrC104 (Tr = Ph sC), thereby affording a good route to 1,2-cis furanosides that are difficult to obtain by other means (Scheme 2.6, Table 2.2) [7]. 

One of the commercial benefits of this route is the value of the coproducts, tertiary butyl alcohol (TBA) when isobucane is used, and styrene when ethylbenzene is used. TBA also can be easily hydro-treated back to isobutane if a recycle stream for PO manufacture is more advantageous. 

Synthesis gas can be tailored in this manner to fit any number of specific applications. For example, a commercial route to aldehydes (the R-CHO signature group) and alcohols (the R-OH signature group) is the Oxo reaction, as discussed in the section on normal butyl alcohol in Chapter 14. In that reaction, the CO H2 ratio needed is I . Careful adjustment of the three feedstocks, CH4, C02, and H2O and the amount of recycling will give this combination. 

Normal butyl alcohol (NBA) was first recovered in the 1920s as a by-product of acetone manufacture via cornstarch fermentation. That route is almost extinct now. A small percent is still made from acetaldehyde. The primary source of NBA, however, is the Oxo process. 

Unfortunately, secondary and tertiary butyl alcohols (SBA and TBA) cannot be made by the Oxo process. Instead they are produced either by indirect or direct hydration of the corresponding olefin. Normal butylene gives SBA and isobutylene gives TBA. The processes are similar to the corresponding routes to IPA. 

The epoxidation of propylene to propylene oxide is a high-volume process, using about 10% of the propylene produced in the world via one of two processes [127]. The oldest technology is called the chlorohydrin process and uses propylene, chlorine and water as its feedstocks. Due to the environmental costs of chlorine and the development of the more-efficient direct epoxidation over Ti02/Si02 catalysts, new plants all use the hydroperoxide route. The disadvantage here is the co-production of stoichiometric amounts of styrene or butyl alcohol, which means that the process economics are dependent on finding markets not only for the product of interest, but also for the co-product The hydroperoxide route has been practiced commercially since 1979 to co-produce propylene oxide and styrene [128], so when TS-1 was developed, epoxidation was looked at extensively [129]. 

Dinitrocubane (28) has been synthesized by Eaton and co-workers via two routes both starting from cubane-l,4-dicarboxylic acid (25). The first of these routes uses diphenylphos-phoryl azide in the presence of a base and tert-butyl alcohol to effect direct conversion of the carboxylic acid (25) to the tert-butylcarbamate (26). Hydrolysis of (26) with mineral acid, followed by direct oxidation of the diamine (27) with m-CPBA, yields 1,4-diiutrocubane (28). Initial attempts to convert cubane-l,4-dicarboxylic acid (25) to 1,4-diaminocubane (27) via a Curtins rearrangement of the corresponding diacylazide (29) were abandoned due to the extremely explosive nature of the latter. However, subsequent experiments showed that treatment of the acid chloride of cubane-l,4-dicarboxylic acid with trimethylsilyl azide allows the formation of the diisocyanate (30) without prior isolation of the dangerous diacylazide (29) from solution. Oxidation of the diisocyanate (30) to 1,4-dinitrocubane (28) was achieved with dimethyldioxirane in wet acetone. Dimethyldioxirane is also reported to oxidize both the diamine (27) and its hydrochloride salt to 1,4-dinitrocubane (28) in excellent yield. ... 

There are currendy three important processes for the production of isobutylene (/) the extraction process using an acid to separate isobutylene (2) the dehydration of tert-butyl alcohol, formed in the Arco s Oxiiane process and (i) the cracking of MTBE. The expected demand for MTBE will preclude the third route for isobutylene production. Since MTBE is likely to replace tert-buty alcohol as a gasoline additive, the second route could become an important source for isobutylene. Nevertheless, its availability will be limited by the demand for propylene oxide, since it is only a coproduct. An alternative process is emerging that consists of catalytically hydroisomerizing 1-butene to 2-butenes (82). In this process, trace quantities of butadienes are also hydrogenated to yield feedstocks rich in isobutylene which can then be easily separated from 2-butenes by simple distillation. 

Irradiation of several members of the cannabinoid family has provided useful routes to some derivatives. Cannabichromene (576) is converted into cannabicyclol (577) when it is irradiated in r-butyl alcohol-acetone <71JCS(C)796) and tetrahydrocannabinolic acid (578) is aromatized to cannabinolic acid (579) (70CPB1327). 

Isobutylene-Based butyl alcohol can be converted to methacrylic acid in a iwo-siage. gas-phase oxidation process via methacrolein as an intermediate. The alcohol and isobutylene may he used interchangeably in Ihe processes since fe/f-bnlyl alcohol readily dehydrates lo yield isobutylene under Ihe reaction conditions in the initial oxidation. Variations of this process have been commercialized. 

A dilute solution of ethanol is obtained, which can be concentrated by distillation to a constant-boiling point mixture that contains 95.6% ethanol by weight. Dehydration of the remaining few percent of water to give absolute alcohol is achieved either by chemical means or by distillation with benzene, which results in preferential separation of the water. Ethanol also is made in large quantities by fermentation, but this route is not competitive for industrial uses with the hydration of ethene. Isopropyl alcohol and tert-butyl alcohol also are manufactured by hydration of the corresponding alkenes. 

Other routes to methyl methacrylate include starting with t-butyl alcohol and ethylene ... 

Fermentation processes produce a wide range of chemicals that complement the various chemicals produced by nonfermentation routes. For example, alcohol, acetone, butyl alcohol, and acetic acid are produced by fermentation as well as by synthetic routes. Almost all the major antibiotics are obtained from fermentation processes. 

The economics of any manufacturing process improves if the co-product or side product has a market. 90% of the world production of phenol is through the cumene hydroperoxide route because of the economic advantage of the coproduct acetone. Oxirane technology for the production of propylene oxide from ethyl benzene leads to a co-product styrene and from isobutane leads to a co-product /-butyl alcohol. 

Isobutene is present in refinery streams. Especially C4 fractions from catalytic cracking are used. Such streams consist mainly of n-butenes, isobutene and butadiene, and generally the butadiene is first removed by extraction. For the purpose of MTBE manufacture the amount of C4 (and C3) olefins in catalytic cracking can be enhanced by adding a few percent of the shape-selective, medium-pore zeolite ZSM-5 to the FCC catalyst (see Fig. 2.23), which is based on zeolite Y (large pore). Two routes lead from n-butane to isobutene (see Fig. 2.24) the isomerization/dehydrogenation pathway (upper route) is industrially practised. Finally, isobutene is also industrially obtained by dehydration of f-butyl alcohol, formed in the Halcon process (isobutane/propene to f-butyl alcohol/ propene oxide). The latter process has been mentioned as an alternative for the SMPO process (see Section 2.7). 

SAFETY PROFILE Poison by intravenous and intraperitoneal routes. Mildly toxic by ingestion. Experimental reproductive effects. A skin and eye irritant. See also n-BUTYL ALCOHOL and ALCOHOLS. Dangerous fire hazard when exposed to heat or flame. Auto-oxidizes to an explosive peroxide. Ignites on contact with chromium trioxide. To fight fire, use water spray, alcohol foam, CO2, dry chemical. Incompatible with oxidizing materials. 

OSHA PEL TWA 5 ppm ACGIH TLV TWA 5 ppm SAFETY PROFILE Poison by intrapetitoneal route. A skin irritant. Toxic concentration in air for humans is about 4 ppm. Flammable when exposed to heat or flame can react with oxidizing materials. To fight fire, use alcohol foam, foam, CO2, dry chemical. When heated to decomposition it emits acrid smoke and irritating fumes. See also ESTERS, n-BUTYL ALCOHOL, and LACTIC ACID. 

SAFETY PROFILE A poison by ingestion and intraperitoneal routes. Mildly toxic by inhalation. An irritant. Human systemic effects by ingestion methemoglobinemia-carboxyhemoglobinemia. Resembles amyl nitrite in causing fall in blood pressure, headache, pulse throbbing, and weakness. Mutation data reported. Flammable when exposed to heat or flame or by spontaneous chemical reaction. When heated to decomposition it emits toxic fumes of NOx. See also NITRITES, n-BUTYL ALCOHOL, and ESTERS. 

SAFETY PROFILE Poison by intraperitoneal route. Moderately toxic by ingestion. Mildly toxic by skin contact. An eye and skin irritant. See also ESTERS and n-BUTYL ALCOHOL. Combustible when... 

Rodent and human studies have shown that MTBE is rapidly absorbed following inhalation exposure. In addition, rodent studies have shown rapid distribution of MTBE after oral and intraperitoneal exposure. Dermal absorption occurs more slowly. Evidence supports metabolic transformation of MTBE by P450 enzymes to the parent alcohol, t-butyl alcohol (TBA), and formaldehyde in rodents and humans. Further oxidative metabolism of TBA seems to be slow, and glucuronidation is a major competing pathway. Formaldehyde metabolism to formate is very rapid. The toxicokinetic parameters of MTBE and TBA depend on the dose and route of administration although they appear to be linear following inhalation exposures up to 50 ppm. 

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