Article No : a01_031 Acetaldehyde MARC ECKERT, Wacker Chemie AG, Werk Burghausen, Germany GERALD FLEISCHMANN, Wacker Chemie AG, Werk Burghausen, Germany REINHARD JIRA, Wacker Chemie AG, Werk Burghausen, Germany HERMANN M. BOLT, Institut fur€ Arbeitsphysiologie an der Universit€at Dortmund, Dortmund, Germany KLAUS GOLKA, Institut fur€ Arbeitsphysiologie an der Universit€at Dortmund, Dortmund, Germany 1. Introduction........................ 191 4.3.3. Isomerization of Ethylene Oxide . ...... 200 2. Physical Properties .................. 192 4.4. Production from C1 Sources ........... 200 3. Chemical Properties and Uses .......... 193 4.5. Production from Hydrocarbons......... 201 3.1. Addition Reactions................... 193 5. Quality and Analysis ................. 201 3.2. Derivatives of Aldol Addition .......... 193 6. Storage and Transportation............ 201 3.3. Reaction with Nitrogen Compounds ..... 193 6.1. Storage............................ 201 3.4. Oxidation.......................... 194 6.2. Transportation...................... 201 3.5. Reduction.......................... 194 6.3. Other Regulations ................... 202 3.6. Miscellaneous Reactions .............. 194 7. Economic Aspects ................... 202 3.7. Consumption ....................... 194 8. Polymers of Acetaldehyde ............. 203 4. Production ......................... 194 8.1. Paraldehyde........................ 203 4.1. Production from Ethanol.............. 195 8.2. Metaldehyde ....................... 203 4.2. Production from Acetylene ............ 196 8.3. Polyacetaldehyde .................... 204 4.3. Production from Ethylene ............. 197 9. Toxicology and Occupational Health ..... 204 4.3.1. Direct Oxidation of Ethylene . .......... 197 References ......................... 205 4.3.2. Acetaldehyde as Byproduct . .......... 200 1. Introduction 1914 and 1918 in Germany (Wacker-Chemie and Hoechst) and in Canada (Shawinigan). Acetaldehyde is an intermediate in the metab- Acetaldehyde (ethanal), CH3CHO [75-07-0], was observed in 1774 by SCHEELE during reaction olism of plant and animal organisms, in which it of black manganese dioxide and sulfuric acid can be detected in small amounts. Larger with alcohol. Its constitution was explained in amounts of acetaldehyde interfere with biologi- 1835 by LIEBIG who prepared pure acetaldehyde cal processes. As an intermediate in alcoholic by oxidation of ethanol with chromic acid and fermentation processes it is present in small designated this product ‘‘aldehyde,’’ a contrac- amounts in all alcoholic beverages, such as beer, tion of the term ‘‘alcohol dehydrogenatus.’’ wine, and spirits. Acetaldehyde also has been Acetaldehyde is a mobile, low-boiling, highly detected in plant juices and essential oils, roasted flammable liquid with a pungent odor. Because coffee, and tobacco smoke. of its high chemical reactivity, acetaldehyde is an Commercial production processes include important intermediate in the production of dehydrogenation or oxidation of ethanol, addi- acetic acid, acetic anhydride, ethyl acetate, tion of water to acetylene, partial oxidation of peracetic acid, butanol, 2-ethylhexanol, pentaer- hydrocarbons, and direct oxidation of ethylene. ythritol, chlorinated acetaldehydes (chloral), In the 1970s, the world capacity of this last glyoxal, alkyl amines, pyridines, and other che- process, the Wacker-Hoechst direct oxidation, micals. The first commercial application was the increased to over 2Â106 t/a. However, the production of acetone via acetic acid between importance of acetaldehyde as an organic Ó 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim DOI: 10.1002/14356007.a01_031.pub2 192 Acetaldehyde Vol. 1 Heat capacity of liquid intermediate is now steadily decreasing, because À1 À1 cp (l) at 0 C 2.18 J g K new processes for some acetaldehyde derivatives at 20 C 1.38 J gÀ1 KÀ1 À1 À1 have been developed, such as the oxo process for For further values between À80 C(cp ¼ 1.24 J g K ) and À1 À1 butanol and 2-ethylhexanol and the Monsanto þ120 C(cp ¼ 1.50 J g K ), see [17]. Heat capacity of vapor process for acetic acid. In the future, new pro- À1 À1 cp (g) at 25 C, 101.3 kPa 1.24 J g K cesses for acetic anhydride (Halcon, Eastman, For dependence on temperature (nonlinear) between 0 C À1 À1 Hoechst), for vinyl acetate (Halcon), and for (cp ¼ 1.17 J g K ) and 1000 C À1 À1 alkyl amines (from ethanol) will diminish the (cp ¼ 2.64 J g K ), see [17]. / (¼ k)at30C, 101.3 kPa 1.145 [18] use of acetaldehyde as a starting material. cp cv Thermal conductivity of liquid at 20 C 0.174 J mÀ1 sÀ1 KÀ1; for more values, see [19] 2. Physical Properties of vapor at 25 C 1.09Â10À2 JmÀ1 sÀ1 KÀ1 for further values, see [20]. Cubic expansion coefficient per K 0.00169 Acetaldehyde, C2H4O, Mr 44.054, is a colorless (0 – 20 C) liquid with a pungent, suffocating odor that is Heat of combustion of liquid at 1168.79 (1166.4 [12]) kJ/mol slightly fruity when diluted. constant p Heat of solution in water (infinite 17 906 J/mol dilution) Latent heat of fusion 3246.3 J/mol Latent heat of vaporization at 20.2 C 25.73 kJ/mol bp at 101.3 kPa 20.16 C other values 27.2 [21], 30.41, mp –123.5 C 27.71 [12], 26.11 [22] kJ/mol Critical temperature tcrit 181.5 C For dependence on temperature (nonlinear) between -80 C other values 187.8 C [12], 195.7 C [13] (32.46 kJ/mol) and 182 C (0 kJ/mol), see [17]. Critical pressure 6.44 MPa pcrit Heat of formation DH from the elements at 25 C for gaseous other values 5.54 MPa [12], 7.19 MPa [13] acetaldehyde Relative density t ¼ 0:8045À0:001325Á d4 t À166.47 (À166.4 [21]) kJ/mol (t in C) [3] For dependence of heat of formation for gaseous and liquid Refractive index t ¼ 1:34240À0:0005635Á nD t acetaldehyde, and enthalpy of vaporization on temperature (t in C) [14] up to 800 K and 30 MPa, see [15]. Molar volume of the gas Gibbs free energy of formation D from elements G at 101.3 kPa and 20.16 C 23.40 L/mol at 25 C for gaseous À133.81 kJ/mol at 25.0 C 23.84 L/mol acetaldehyde For dependence on T (293.32 – 800 K) and p (0.1 – 30 MPa), see [15]. other values 133.72 [12], 132.9 [21] kJ/mol Specific volume of the vapor Entropy for gaseous acetaldehyde 3 at 20.16 C 0.531 m /kg at 25 C 265.9 J molÀ1 KÀ1 3 at 25.0 C 0.541 m /kg Entropy for liquid acetaldehyde Vapor density (air ¼ 1) 1.52 at 20.16 C 172.9 J molÀ1 KÀ1 Entropy of vaporization at 20.16 C 91.57 J molÀ1 KÀ1 First ionization potential 10.5 eV À14 Vapor pressure Dissociation constant at 0 C 0.7Â10 mol/L (H CCHOÀH CCHO þ Hþ) t, C À20 À0.27 5.17 14.76 50 100 3 2 , kPa 16.4 43.3 67.6 82.0 279.4 1014.0 For the second virial coefficient of the equation of state for gaseous p For further values between À60 and þ180 C, see [14] acetaldehyde at 31 C, 66 C, and 85 C, see [23]. Acetaldehyde is completely miscible with water and most organic solvents. It forms no Viscosity of liquid h azeotrope with water, methanol, ethanol, ace- at 9.5 C 0.253 mPa Á s tone, acetic acid, or benzene. Binary azeotropes at 20 C 0.21 mPa Á s Viscosity of vapor h are formed with butane (bp À7 C, 84 wt % of at 25 C86Â10À4 mPa Á s butane) and diethyl ether (bp 18.9 C, 23.5 wt % For further values between 35.0 and 77.8 C and between 0.13 of ether). and 0.40 kPa, see [16]. Surface tension g at 20 C 21.2Â10À2 mN cmÀ1 Dipole moment (gas phase) 2.69 Æ 2 % D [12] Compressibility and Dielectric constant Other Physical Data. of liquid at 10 C 21.8 viscosity at higher pressure are given in [24], of vapor at 20.16 C, 101.3 kPa 1.0216 vapor pressure of aqueous acetaldehyde solutions Vol. 1 Acetaldehyde 193 in [25]. For solubility of carbon dioxide, acety- the vinyl acetate process of Celanese Corp. [31] lene, and nitrogen in acetaldehyde, see [11]; for (! Vinyl Esters). freezing points of aqueous acetaldehyde solutions, see [11]; for vapor – liquid equilibria of binary systems of acetaldehyde with water, 3.2. Derivatives of Aldol Addition ethanol, acetic acid, and ethylene oxide, see [26], pp. 392, 561, 565, and 570], with vinyl acetate, Two molecules of acetaldehyde combine in the see [27]. presence of alkaline catalysts or dilute acids at room temperature or with moderate heating to Safety Data. Flash point (Abel – Pensky; form acetaldol [107-89-1], CH3CH(OH) DIN 51 755; ASTM 56 – 70) À20 C(À40 C CH2CHO. At increased temperatures, water is according to the safety regulations of the cleaved easily from this acetaldol, forming Berufsgenossenschaft der Chemischen Industrie, crotonaldehyde (! Aldehydes, Aliphatic). Fur- Federal Republic of Germany). Ignition temper- ther condensation under more stringent condi- ature (DIN 51 794; ASTM D 2155 – 66) 140 C; tions to form aldehyde resins (e.g., synthetic for ignition retardation when injected into a shellac) now has no industrial importance. hot air stream, see [28]. Explosive limits in air: 4 – 57 vol %; for influence of pressure on Urea and acetaldehyde condense in the pres- explosive limits, see [29]. ence of H2SO4 to form crotonylidenediurea (6-methyl-4-ureidohexahydropyrimidin-2-one [1129-42-6]),whichisusedasalong-term 3. Chemical Properties and Uses nitrogen fertilizer (! Fertilizers, 1. General). Acetaldehyde is also an intermediate in the Acetaldehyde is a highly reactive compound butadiene synthesis starting from acetylene and showing all of the typical aldehyde reactions as proceeding via acetaldol and its hydrogenation well as those of an alkyl group in which hydrogen product, 1,3-butanediol [32]. This process was atoms are activated by the carbonyl group in the introduced around 1918 and is still carried out on a position.