Alcohols carbon monoxide addition

The addition of alcohols to form the 3-alkoxypropionates is readily carried out with strongly basic catalyst (25). If the alcohol groups are different, ester interchange gives a mixture of products. Anionic polymerization to oligomeric acrylate esters can be obtained with appropriate control of reaction conditions. The 3-aIkoxypropionates can be cleaved in the presence of acid catalysts to generate acrylates (26). Development of transition-metal catalysts for carbonylation of olefins provides routes to both 3-aIkoxypropionates and 3-acryl-oxypropionates (27,28). Hence these are potential intermediates to acrylates from ethylene and carbon monoxide. 

The 0X0 and aldol reactions may be combined if the cobalt catalyst is modified by the addition of organic—soluble compounds of 2inc or other metals. Thus, propylene, hydrogen, and carbon monoxide give a mixture of aldehydes and 2-ethylhexenaldehyde [123-05-7] which, on hydrogenation, yield the corresponding alcohols. 

Often the aldehyde is hydrogenated to the corresponding alcohol. In general, addition of carbon monoxide to a substrate is referred to as carbonylation, but when the substrate is an olefin it is also known as hydroformylation. The eady work on the 0x0 synthesis was done with cobalt hydrocarbonyl complexes, but in 1976 a low pressure rhodium-cataly2ed process was commerciali2ed that gave greater selectivity to linear aldehydes and fewer coproducts. 

Use of alcohol as a solvent for carbonylation with reduced Pd catalysts gives vinyl esters. A variety of acrylamides can be made through oxidative addition of carbon monoxide [630-08-0] CO, and various amines to vinyl chloride in the presence of phosphine complexes of Pd or other precious metals as catalyst (14). 

A l-Iiter, three-necked, round-bottom flask is equipped with a mechanical stirrer, a thermometer immersed in the reaction mixture, a dropping funnel, and a gas vent. In the flask is placed a mixture of 96% sulfuric acid (25.5 ml, 470 g, 4.8 mole), carbon tetrachloride (100 ml), and adamantane (13.6 g, 0.10 mole), and the mixture is cooled to 15-20° with rapid stirring in an ice bath. One milliliter of 98% formic acid is added and the mixture is stirred until the evolution of carbon monoxide is rapid (about 5 minutes). A solution of 29.6 g (38 ml, 0.40 mole) of t-butyl alcohol in 55 g (1.2 mole) of 98-100% formic acid is then added dropwise to the stirred mixture over 1-2 hours, the temperature being maintained at 15-20°. After stirring for an additional 30 minutes, the mixture is poured onto 700 g of ice, the layers are separated, and the aqueous (upper) layer is extracted three times with lOO-ml portions of carbon tetrachloride. The combined carbon tetrachloride solutions are shaken with 110 ml of 15 A ammonium hydroxide, whereupon ammonium 1-adamantanecarboxylate forms as a crystalline solid. This precipitate is collected by filtration through a fritted glass funnel and washed... 

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. 

If the reaction between trialkylboranes and carbon monoxide (18-23) is carried out in the presence of water followed by addition of NaOH, the product is a secondary alcohol. If H2O2 is added along with the NaOH, the corresponding ketone is obtained instead. Various functional groups (e.g., OAc, COOR, CN) may be present in R without being affected,though if they are in the a or p position relative to the boron atom, difficulties may be encountered. The use of an equimolar... 

Organopalladium(n) intermediates generated from halides or triflates by oxidative addition react with carbon monoxide in the presence of alcohols to give carboxylic acids246 or esters.247... 

Since 1985, several thousands of publications have appeared on complexes that are active as catalysts in the addition of carbon monoxide in reactions such as carbonylation of alcohols, hydroformylation, isocyanate formation, polyketone formation, etc. It will therefore be impossible within the scope of this chapter to review all these reports. In many instances we will refer to recent review articles and discuss only the results of the last few years. Second, we will focus on those reports that have made use explicitly of coordination complexes, rather than in situ prepared catalysts. Work not containing identified complexes but related to publications discussing well-defined complexes is often mentioned by their reference only. Metal salts used as precursors on inorganic supports are often less well defined and most reports on these will not be mentioned. 

The essential factor which differentiates the monomeric and dimeric carbonylations seems to be the presence or absence of halide ion coordinated to the palladium. The dimerization-carbonylation proceeds satisfactorily with halide-free palladium phosphine complexes. Most conveniently, Pd(OAc)2 is used with PPh3. PdCl2(PPh3)2 can be used as a catalyst with addition of an excess of bases. The reaction is carried out at 1I0°C under 50 atm of carbon monoxide pressure in alcohol. Higher... 

Some distinctive features of the insertion reactions reported in Table VII can be summarized as follows First, carbon monoxide gives rise by insertion (5, 195a) to acyl bonds which are easily cleaved by water, alcohols, or compounds with mobile hydrogen. The metal is thus easily removed from the organic part and, being eliminated in its reduced state, can undergo a further oxidative addition, leading to a catalytic cycle. Thus, use of CO is very favorable for catalytic reactions. 

Carbon monoxide rapidly inserts into the carbon—zirconium bond of alkyl- and alkenyl-zirconocene chlorides at low temperature with retention of configuration at carbon to give acylzirconocene chlorides 17 (Scheme 3.5). Acylzirconocene chlorides have found utility in synthesis, as described elsewhere in this volume [17]. Lewis acid catalyzed additions to enones, aldehydes, and imines, yielding a-keto allylic alcohols, a-hydroxy ketones, and a-amino ketones, respectively [18], and palladium-catalyzed addition to alkyl/aryl halides and a,[5-ynones [19] are examples. The acyl complex 18 formed by the insertion of carbon monoxide into dialkyl, alkylaryl, or diaryl zirconocenes may rearrange to a r 2-ketone complex 19 either thermally (particularly when R1 = R2 = Ph) or on addition of a Lewis acid [5,20,21]. The rearrangement proceeds through the less stable... 

For preparative purposes the method of obtaining aldehydes from the primary alcohols is preferable by far, at least in the aliphatic series. The simple aromatic aldehydes can be obtained by alkaline hydrolysis of the arylidene chlorides, R.CHC12, which are produced from the hydrocarbons by substitution with chlorine (technical method for the preparation of benzaldehyde). In addition to these methods the elegant synthesis of Gattermann and Koch should be mentioned here. This synthesis, which proceeds like that of Friedel-Crafts, consists in acting on the aromatic hydrocarbon with carbon monoxide and hydrogen chloride in the presence of aluminium chloride and cuprous chloride. 

Carbon monoxide will also add to aromatic coumpounds such as benzene and toluene. As the product of such an addition is an aldehyde and as aromatic aldehydes readily polymerize under the conditions necessary for the addition of carbon monoxide, the simple addition product is not obtained. These reactions have been performed in the author s laboratory using a technique similar to the addition to alcohols and alkyl halides. The products obtained are the same shellac-like resins that are obtained by treating the theoretically expected aldehyde with hydrogen fluoride under the same conditions. 

In solution these esters undergo a variety of transformations which are dependent on the reaction conditions. In benzene, decomposition to carbon monoxide and carbonyl compounds is observed either upon direct irradiation94 or with benzophenone sensitization.33 In cyclohexane a complex product mixture is obtained.95 Addition of solvent to the carbonyl group is observed when the reaction is carried out in cyclohexene.54 At room temperature photoreduction takes place when the reaction is carried out in a secondary alcohol.96-97 However, in the case of the phenylglyoxylates quite a different reaction is observed when the reaction is carried out at elevated temperatures. The ester is reduced to the mandelate ester of the solvent alcohol, and the alcohol moiety of the ester is oxidized to the corresponding carbonyl compound. The pyruvates have not been studied at an elevated temperature. 

Primary alcohol and aldehydes are produced from butene through the Oxo process. The Oxo process involves the addition of carbon monoxide and hydrogen to an alkene under elevated temperature and pressure in the presence of a catalyst. 

In the 1940 s, in addition to these operations, two other processes became important. Acetic acid was made by reacting methanol with carbon monoxide, and acetic anhydride was being made by the ethylidene diacetate process, which in effect is the dehydration of acetic acid to the anhydride by the use of acetylene. Fermentation ethyl alcohol was converted to acetic acid via acetaldehyde as well as by the direct oxidation of ethyl alcohol. A new operation on the Gulf Coast was also based on acetaldehyde. However, the acetaldehyde is made by the direct oxidation of liquefied petroleum gas. A further process for the production of these materials, in which acetaldehyde is oxidized in one step to a mixture of anhydride and acid, was also begun. 

Alkenes can be converted to succinic esters by reaction with carbon monoxide, an alcohol, and palladium chloride in the presence of mercuric chloride.1,12 The addition is mostly syn. In similar reaction, both terminal and internal alkynes can be converted to esters of maleic acid. 

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