6004-44-0

Basic information

• Product Name: methylketene
• Synonyms: methylketene
• CAS NO: 6004-44-0
• Molecular Formula: C₃H₄O
• Molecular Weight: 56.06
• Mol File: 6004-44-0.mol
• Article Data: 30

Chemical Properties

• Boiling Point: 23.66°C (rough estimate)
• Flash Point: 191.1°C
• Appearance: /
• Density: 0.7450 (rough estimate)
• Vapor Pressure: 2.31E-06mmHg at 25°C
• Refractive Index: 1.3810 (estimate)
• CAS DataBase Reference: methylketene(CAS DataBase Reference)
• NIST Chemistry Reference: methylketene(6004-44-0)
• EPA Substance Registry System: methylketene(6004-44-0)

Safety Data

• Hazardous Substances Data: 6004-44-0(Hazardous Substances Data)

Usage

General Description

Methylketene is a highly reactive chemical compound with the formula CH3COCH=CH2. It is a colorless liquid at room temperature, but is unstable and can decompose explosively when heated or exposed to moisture. Methylketene is primarily used as an intermediate in the production of pharmaceuticals, agrochemicals, and specialty chemicals. It is also used in the synthesis of various organic compounds and as a reagent in organic chemistry reactions. However, due to its highly reactive nature and potential hazards, strict safety precautions must be taken when handling and storing methylketene to prevent accidents and exposure.

InChI:InChI=1/C15H18ClNO5/c1-4-21-14(18)11(15(19)22-5-2)9-17-12-8-10(16)6-7-13(12)20-3/h6-9,17H,4-5H2,1-3H3

Upstream product

• 563-76-8 α-bromopropionyl bromide 
• 637-27-4 phenyl propionate 
• 802294-64-0 propionic acid 
• 78-93-3 butanone 
• 68228-45-5 1-propionyl-1,2,4-triazole 
• 89489-29-2 1-isopropoxy-1-propyne 
• 89896-71-9 1-tert-butoxy-1-propyne 
• 17158-30-4 propionyl cation 
• 67-64-1 acetone 
• 14273-06-4 1-ethoxy-1-propyne 
• 107-02-8 acrolein 
• 7148-74-5 2-Bromopropionyl chloride 
• 74-99-7 prop-1-yne 
• 2905-39-7 N-thioacetylpropanamide 

Downstream Products

• 107-01-7 butene-2 
• 72251-52-6 t-butyl 3-hydroxy-2-methyl-5-phenylpentanethiolate 
• 4683-23-2 1,3-Dimethyl-cyclobuten-⁽¹⁾-ol-⁽²⁾-on-⁽⁴⁾-propionat, trimeres Methylketen 
• 71908-06-0 erythro-S-(1,1-dimethylethyl) 3-hydroxy-2-methyl-3-phenylpropanethioate 
• 104805-11-0 (2S,3R)-3-Hydroxy-2-methyl-3-phenyl-thiopropionic acid S-pyridin-2-yl ester 
• 104805-11-0 (2R,3R)-3-Hydroxy-2-methyl-3-phenyl-thiopropionic acid S-pyridin-2-yl ester 
• 68364-34-1 3-Methyl-4-(1-cyano-2,2-dimethylpropylidine)-2-oxetane-1-one 
• 2857-97-8 trimethylsilyl bromide 
• 70688-37-8 2-bromopropanoyl cyanide 
• 76837-52-0 (Z)-2-(Trimethylsilyloxy)-2-butennitril 
• 76837-53-1 (E)-2-(Trimethylsilyloxy)-2-butennitril 
• 74632-85-2 erythro-3-Methyl-1-phenyl-4-(α-styryl)azetidin-2-on 
• 74632-85-2 trans-3-methyl-1-phenyl-4-[(E)-2-phenylethenyl]azetidin-2-one 
• 89710-53-2 (2R,3S,4S)-2,3,4-Trimethyl-3-trimethylsilanyloxy-cyclobutanone 

Relevant articles and documents

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CeO2 Facet-Dependent Surface Reactive Intermediates and Activity during Ketonization of Propionic Acid

CeO2 rods, octahedrons, and cubes exposing well-defined (110), (111), and (100) surfaces, respectively, were synthesized and investigated for the catalytic ketonization of propionic acid. The intrinsic ketonization rates at 350 °C on the rods, octahedrons, and cubes are 54.3, 40.4, and 25.1 mmol·m-2·h-1, respectively, indicating that the (110) facet is the most active surface for ketonization. The reaction was tracked by both in situ infrared and mass spectroscopies under transient conditions, and the results showed that monodentate propionate, a minority surface species, is responsible for the formation of 3-pentanone. In contrast, bidentate propionate, a dominant species on all three surfaces, appears to a spectator for ketonization. Moreover, the ketonization activity can be correlated with relative concentration of monodentate propionate. A density functional theory study showed that the relative concentration of monodentate propionate (or the adsorption energy difference between monodentate and bidentate configurations) at high coverages is strongly dependent on the surface geometry. The stability of monodentate propionate on the (110) surface exposing both the O and Ce sites in the outermost layer with the well-separated Ce sites exhibits little dependence on the propionate coverage. In contrast, strong steric hindrance due to the top layer O atom and the closely packed Ce atoms in (111) destabilizes monodentate propionate significantly at high coverages. This study demonstrates that the surface geometrical structure of CeO2 can determine the abundance of the active monodentate propionate, which, in turn, will determine the catalytic activity of CeO2 for ketonization.

Decomposition of malonic anhydrides

Malonic anhydrides decompose at or below room temperature, to form a ketene and carbon dioxide. Rate constants for the thermal decomposition of malonic, methylmalonic, and dimethylmalonic anhydrides were measured by NMR spectroscopy at various temperatures, and activation parameters were evaluated from the temperature dependence of the rate constants. Methylmalonic anhydride is the fastest, with the lowest δH?, and dimethylmalonic anhydride is the slowest. The nonlinear dependence on the number of methyl groups is discussed in terms of a concerted [2s + (2s + 2s)] or [2s + 2a] cycloreversion that proceeds via a twisted transition-state structure, supported by computations.