Reaction of hydroformylation

Another side reaction of hydroformylation is formate ester formation (11). The 4% yield of formates did not change in the temperature range examined or with lower CO partial pressure. 

This reaction is observed as a side reaction of hydroformylation. With ethylene the formation of diethyl ketone can be optimized to give high product selectivities, however, with higher, especially unsymmetrically substituted alkenes, only low ketone product selectivities and re-gioselectivities are observed. Thus, the reaction is only rarely applied to open chain ketone synthesis and little information is available about the stereochemistry of this reaction type1 -3. 

In September 2007, following my nomination as a university lecturer at the University of Strasbourg, I joined the laboratory of Dr. Andre Mann in the faculty of pharmacy at Strasbourg. The recent work of this laboratory concerned the reaction of hydroformylation. They had just published an article on the synthesis of derivatives of kainic acid by cyclohydrocarbonylation (CHC) in collaboration with Professor Ojima, and another on olefin hydroa minomethylations assisted by microwave irradiation with Professor Taddei. One year before my arrival, a research student had the role of continuing... 

The ortho-metalation reaction of hydroformylation catalysts has been found to occur also during the distillation of the reaction mixture of a continuously driven hydroformylation reaction. Especially in the presence of excess of olefin and after stripping hydrogen with pure carbon monoxide, the formation of ortho-metalated... 

Hydrogenation of olefins to paraffins has already been mentioned as a side reaction of hydroformylation. The formation of formate esters is also frequently encountered, especially at higher temperatures (see the next section). 

Hydroformylation (Section 17 5) An industrial process for prepanng aldehydes (RCH2CH2CH=0) by the reaction of terminal alkenes (RCH=CH2) with carbon monoxide Hydrogenation (Section 6 1) Addition of H2 to a multiple bond... 

Aliphatic Aldehyde Syntheses. Friedel-Crafts-type aUphatic aldehyde syntheses are considerably rarer than those of aromatic aldehydes. However, the hydroformylation reaction of olefins (185) and the related oxo synthesis are effected by strong acid catalysts, eg, tetracarbonylhydrocobalt, HCo(CO)4 (see Oxo process). 

Prior to 1975, reaction of mixed butenes with syn gas required high temperatures (160—180°C) and high pressures 20—40 MPa (3000—6000 psi), in the presence of a cobalt catalyst system, to produce / -valeraldehyde and 2-methylbutyraldehyde. Even after commercialization of the low pressure 0x0 process in 1975, a practical process was not available for amyl alcohols because of low hydroformylation rates of internal bonds of isomeric butenes (91,94). More recent developments in catalysts have made low pressure 0x0 process technology commercially viable for production of low cost / -valeraldehyde, 2-methylbutyraldehyde, and isovaleraldehyde, and the corresponding alcohols in pure form. The producers are Union Carbide Chemicals and Plastic Company Inc., BASF, Hoechst AG, and BP Chemicals. 

These reactions are also quite sensitive to steric factors, as shown by the fact that if 1-butene reacts with di(j iAisoamyl)borane the initially formed product is 99% substituted in the 1-position (15) compared to 93% for unsubstituted borane. Similarly, the product obtained from hydroformylation of isobutylene is about 97% isoamyl alcohol and 3% neopentyl alcohol (17). Reaction of isobutylene with aluminum hydride yields only triisobutjlaluininum. 

With Unsaturated Compounds. The reaction of unsaturated organic compounds with carbon monoxide and molecules containing an active hydrogen atom leads to a variety of interesting organic products. The hydroformylation reaction is the most important member of this class of reactions. When the hydroformylation reaction of ethylene takes place in an aqueous medium, diethyl ketone [96-22-0] is obtained as the principal product instead of propionaldehyde [123-38-6] (59). Ethylene, carbon monoxide, and water also yield propionic acid [79-09-4] under mild conditions (448—468 K and 3—7 MPa or 30—70 atm) using cobalt or rhodium catalysts containing bromide or iodide (60,61). 

Oxo or Hydroformylation and Hydroesterification. Reactions of alkenes with hydrogen and formyl groups are cataly2ed by HCo(CO)4... 

Addition. Addition reactions of ethylene have considerable importance and lead to the production of ethylene dichloride, ethylene dibromide, and ethyl chloride by halogenation—hydrohalogenation ethylbenzene, ethyltoluene, and aluminum alkyls by alkylation a-olefms by oligomerization ethanol by hydration and propionaldehyde by hydroformylation. 

Hydroformylation, or the 0X0 process, is the reaction of olefins with CO and H9 to make aldehydes, which may subsequently be converted to higher alcohols. The catalyst base is cobalt naph-thenate, which transforms to cobalt hydrocarbonyl in place. A rhodium complex that is more stable and mnctions at a lower temperature is also used. 

Rhodium catalyzed reaction of A -butenyl-l,3-propanediamines 397 with a mixture of H2 and CO gave usually a mixture of hydroformylated 398 and 399 and carbonylated products 400 and 401 in the presence of a phosphite [PPha, PBu3, PCCgHiOa, P(o-tol)3] (97TL4315, 97T17449). When the hindered biphosphite, BIPEPHOS, and a 9 1 or 1 1 mixture of H2 and... 

Synthesis gas is an important intermediate. The mixture of carbon monoxide and hydrogen is used for producing methanol. It is also used to synthesize a wide variety of hydrocarbons ranging from gases to naphtha to gas oil using Fischer Tropsch technology. This process may offer an alternative future route for obtaining olefins and chemicals. The hydroformylation reaction (Oxo synthesis) is based on the reaction of synthesis gas with olefins for the production of Oxo aldehydes and alcohols (Chapters 5, 7, and 8). 

Linear alcohols (C12-C26) are important chemicals for producing various compounds such as plasticizers, detergents, and solvents. The production of linear alcohols by the hydroformylation (Oxo reaction) of alpha olefins followed by hydrogenation is discussed in Chapter 5. They are also produced by the oligomerization of ethylene using aluminum alkyls (Ziegler catalysts). 

The catalytic hydroformylation of olefins is discussed in Chapter 5. The reaction of propylene with CO and H2 produces n-butyraldehyde as the main product. Isobutyraldehyde is a by-product °... 

The carbonyl complex [Ru(EDTAH)(CO)] has been reported to be a very good catalyst for reactions like hydroformylation of alkenes, carbonylation of ammonia and ammines as well as a very active catalyst for the water gas shift reaction. The nitrosyl [Ru(EDTA)(NO)] is an oxygen-transfer agent for the oxidation of hex-l-ene to hexan-2-one, and cyclohexane to the corresponding epoxide. 

Methyl-l-hexanol has also been prepared by the reaction of 2-hexylmagncsium halides with formaldehyde,3 the reduction of 2-mctliylliexanoic acid or its ester,4 5 and by hydroformylation of 1-hexene6"8 among others. 

Higher molecular primary unbranched or low-branched alcohols are used not only for the synthesis of nonionic but also of anionic surfactants, like fatty alcohol sulfates or ether sulfates. These alcohols are produced by catalytic high-pressure hydrogenation of the methyl esters of fatty acids, obtained by a transesterification reaction of fats or fatty oils with methanol or by different procedures, like hydroformylation or the Alfol process, starting from petroleum chemical raw materials. 

The formation of isomeric aldehydes is caused by cobalt organic intermediates, which are formed by the reaction of the olefin with the cobalt carbonyl catalyst. These cobalt organic compounds isomerize rapidly into a mixture of isomer position cobalt organic compounds. The primary cobalt organic compound, carrying a terminal fixed metal atom, is thermodynamically more stable than the isomeric internal secondary cobalt organic compounds. Due to the less steric hindrance of the terminal isomers their further reaction in the catalytic cycle is favored. Therefore in the hydroformylation of an olefin the unbranched aldehyde is the main reaction product, independent of the position of the double bond in the olefinic educt ( contrathermodynamic olefin isomerization) [49]. 

If cobalt carbonylpyridine catalyst systems are used, the formation of unbranched carboxylic acids is strongly favored not only by reaction of a-olefins but also by reaction of olefins with internal double bonds ( contrathermo-dynamic double-bond isomerization) [59]. The cobalt carbonylpyridine catalyst of the hydrocarboxylation reaction resembles the cobalt carbonyl-terf-phos-phine catalysts of the hydroformylation reaction. The reactivity of the cobalt-pyridine system in the hydrocarboxylation reaction is remarkable higher than the cobalt-phosphine system in the hydroformylation reaction, especially in the case of olefins with internal double bonds. This reaction had not found an industrial application until now. 

The chemo- and regioselectivities of hydroformylation reactions of open chain, conjugated dienes using the usual catalyst are, in most cases, rather low [36]. The rhodium/ mesitylene co-condensate (catalyst A), in the presence of bis(diphenylphosphino)ethane, DPPE, catalyses the hydroformylation of 1,3-butadiene, isoprene, and E,Z)-, 3-pentadiene to the corresponding p,y-unsaturated monoaldehydes, with unusually high chemo- and regioselectivities (Scheme 17). 

The adoption of a second liquid phase has also proved useful in the hydroformylation reaction of propylene for which Ruhrchemie and Rhone-Poulenc have used Rh based water... 

In 1999, Casado et al. developed heterotetranuclear complexes (TiRh3) depicted in Scheme 10.3 with bridging sullido ligands combined with P-donor ligands. These complexes were further tested as catalysts for the asymmetric hydroformylation reaction of styrene. In this process, [CpTi((/i3-S)3 Rh(tfbb 3] was efficiently active under mild conditions (10 bar, CO/H2 = 1 atm, 353 K). In order to explore the effect of the added phosphorus ligand and the possibilities of this system for the asymmetric hydroformylation of styrene, achiral diphosphines such as dppe (l,2-bis(diphenylphosphine)ethane) and... 

Rhodium and cobalt participate in several reactions that are of value in organic syntheses. Rhodium and cobalt are active catalysts for the reaction of alkenes with hydrogen and carbon monoxide to give aldehydes, known as hydroformylation,281... 

The reaction of dicobalt octacarbonyl with [NP(OPh) (OCgH P-Pl O 3)n gives three different phosphine bound cobalt carbonyls. The initial hydroformylation activity of the heterogeneous catalyst... 

Hydroformyl ati on of Polybutadiene - A number of hydroformyl at ion experiments were performed using the automated batch reactor system in order to synthesize the hydroformylated polybutadiene with varying degree of reaction completion (2 to 20% of the total C=C present). The following reaction conditions were employed PBD = 1.55 x 103 mol/m3, RhH(CO) (P(C6HJ3 )3 = 0.58... 

Hydroxymethyl ati on of Polybutadiene - The hydroformyl ated PBD reaction solution obtained above was subsequently hydrogenated directly using the following reaction conditions Hydroformyl ated PBD solution = 75 ml, RuC1H(C0)(P(CcHc)3)3 = 1.05 mol/m3, Hydrogen pressure = 600 psig, Temperature = 1 0 C. 

The overall catalytic reactions involved in the two step synthesis of hydroxymethyl ated PBD are given by Equations 1-6. It can be seen from reactions (1-6) that the addition of -CHO functional group can occur in three ways resulting in the formation of three types of hydroformyl ated PBD repeating units as shown by species A, B or C. Subsequent hydrogenation of units A, B and C result in the formation of hydroxymethylated PBD repeating units A, ... 

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