A-Propiolactone

Semiempirical and ab initio techniques have been applied to the unimolecular decomposition of 2-chloropropanoic acid, which is known to form HC1, CO, and CH3CHO. In keeping with the experimental data, the results suggest that reaction proceeds by a two-step mechanism involving rate-determining formation of intermediate a-propiolactone, which then fragments to form CO and CH3CHO.47... 

The carbonylation of COD PdCl2 complex in aqueous sodium acetate produces /rui7x-2-hydroxy-5-cyclooctenecarboxylic acid /i-lactone (240). The lactone is obtained in 79% yield directly by the carbonylation of the COD complex in aqueous sodium acetate solution[220]. /i-Propiolactone (241) is obtained in 72% yield by the reaction of the PdCC complex of ethylene with CO and water in MeCN at —20 " C. /3-Propiolactone synthesis can be carried out with a catalytic amount of PdCC and a stoichiometric amount of CuCl2[221]. 

Ketene Process. The ketene process based on acetic acid or acetone as the raw material was developed by B. F. Goodrich (81) and Celanese (82). It is no longer used commercially because the intermediate P-propiolactone is suspected to be a carcinogen (83). In addition, it cannot compete with the improved propylene oxidation process (see Ketenes, ketene dimers, and related substances). 

P-Hydroxy acids lose water, especially in the presence of an acid catalyst, to give a,P-unsaturated acids, and frequendy P,y-unsaturated acids. P-Hydroxy acids do not form lactones readily because of the difficulty of four-membered ring formation. The simplest P-lactone, P-propiolactone, can be made from ketene and formaldehyde in the presence of methyl borate but not from P-hydroxypropionic acid. P-Propiolactone [57-57-8] is a usehil intermediate for organic synthesis but caution should be exercised when handling this lactone because it is a known carcinogen. 

Reaction with Lactones. Hydroxycarboxyhc acid ester complexes of titanium are formed by reaction of a tetraalkyl titanate with a lactone, such as P-propiolactone, y-butyrolactone, or valerolactone (35). For example. 

Self-condensation of hydroxypivalic acid (also known as 3-hydroxy-a,a-dimethylpropionic acid and as 2-hydroxy-1,1-dimethylpropionic acid) only yields low molecular weight polymers and it is more convenient to prepare the polymer from pivalolactone (also known as a,a-dimethyl-[3-propiolactone) using tributylphosphine as an initiator Figure 25.28). 

A mixture of 100 g (0.6 mole) of 1-morpholino-l-cyclohexene, 28.8 g (0,4 mole) of /3-propiolactone, and 100 ml of chlorobenzene is placed in a 500-ml round-bottom flask fitted with a condenser (drying tube). The mixture is refluxed for 4 hours. The solvent and excess enamine are removed by distillation at aspirator pressure. (The residue may be distilled to afford the pure morpholide, bp 187-18871 rnm, 1.5090.) Basic hydrolysis may be carried out on the undistilled morpholide. To the crude amide is added 400 ml of 10% sodium hydroxide solution. The mixture is cautiously brought to reflux, and refluxing is continued for 2 hours. The cooled reaction mixture is made acidic (pH 4) and is extracted three times with ether. The combined ether extracts are washed twice with 5 % hydrochloric acid solution and twice with water. The ethereal solution is dried (sodium sulfate), then filtered, and the solvent is removed (rotary evaporator). The residue may be recrystallized from petroleum ether-benzene, mp 64°. 

An alternative route to acrylic esters is via a (3-propiolactone intermediate. The lactone is obtained by the reaction of formaldehyde and ketene, a dehydration product of acetic acid ... 

What is the structure of the polymer produced by treatment of /3-propiolactone with a small amount of hydroxide ion ... 

The reactions of /3-propiolactone with various nucleophiles in 39 percent water-61 percent dioxane at 50 °C provide an example. Figure 10-4 shows the LFER correlation. The reaction constant for this seven-membered series is s = 0.77. It is a measure of the nucleophilic reactivity relative to the reference reaction. 

As an example, an NMR spectrum of a 1,3-dioxolane-/3-propiolactone copolymer, obtained by using a boron-fluoride catalyst, is shown in Fig. 1101. The 1,3-dioxolane (DOL) homopolymer spectrum contains two singlet peaks of area 1 2 numbered 1 and 5, whereas the spectrum of the 0-propiolactone (PL) homopolymer contains two triplet peaks of area 1 1 numbered 2 and 6. Variation of initial feed ratios disclosed that peaks 1,3 and S are associated with the DOL units and that... 

Cell cultures provide infeeted fluids that eontain little debris and can generally be satisfactorily clarified by filtration. Beeause most viral vaccines made fiom cell cultures consist of live attenuated vims, there is no inaetivation stage in their manufacture. There are, however, two important exeeptions inaetivated poliomyelitis vims vaccine is inactivated with dilute formalin or /3-propiolaotone and rabies vaccine is inactivated with /3-propiolactone. The preparation of these inaetivated vaccines also involves a concentration stage, by adsorption and elution of the vims in the case of poliomyelitis vaccine and by ultrafiltration in the case of rabies vaceine. When processing is complete the bulk materials may be stored until needed for blending into final vaccine. Because of the lability of many vimses, however, it is necessary to store most purified materials at temperatures of-70°C. 

Dialkyl dimethyl phosphoramidites (16) react with j8-propiolactone to give the phosphoramidate (17) and the phosphonate (18), A kinetic study suggests a mechanism involving initial attack of phosphorus at saturated carbon to give (17), while a four-centred transition state (19) is invoked to explain the formation of (18). 

Ring-opening polymerization of racemic a-methyl-/J-propiolactone using lipase PC catalyst proceeded enantioselectively to produce an optically active (S)-enriched polymer [68]. The highest ee value of the polymer was 0.50. NMR analysis of the product showed that the stereoselectivity during the propagation resulted from the catalyst enantiomorphic-site control. 

A 1992 patent describes the carbonylation of EO to yield /3-propiolactone using a mixture of Co2(CO)8 and 3-hydroxypyridine.982 A recent re-investigation of this system has indicated that the major product is the alternating copolymer, a polyester, catalyzed by the [Co(CO)4] anion (Scheme 24).983 The synthesis of lactones via this methodology has successfully been achieved using Lewis acidic counter-cations (Scheme 25) 984,985 a similar strategy allows /3-lactams to be... 

Chemical/Physical. Slowly hydrolyzes to hydracrylic acid (Windholz et al., 1983). In a reactor heated to 250 °C and a pressure of 12 mmHg, p-propiolactone decomposed to give equal amounts of ethylene and carbon dioxide (James and Wellington, 1969). 

Benzyp3U ene, see Benzojajpyrene Beosit, see a-Endosulfan, p-Endosulfan Bercema NMC50, see Carbaryl Betaprone, see p-Propiolactone Bexol, see Lindane... 

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