78-85-3

Basic information

• Product Name: 2-Methylacrolein
• Synonyms: Methacrylaldehyde(8CI);2-Formyl-1-propene;2-Methacrolein;2-Methyl-2-propen-1-al;2-Methyl-2-propenal;2-Methylacrolein;2-Methylenepropanal;2-Methylpropenal;Isobutenal;Methacrylic aldehyde;NSC 8260;a-Methylacrolein;a-Methylacrylaldehyde
• CAS NO: 78-85-3
• Molecular Formula: C₄H₆O
• Molecular Weight: 70.08984
• EINECS: 201-150-1
• Mol File: 78-85-3.mol
• Article Data: 169

Chemical Properties

• Melting Point: -81℃
• Boiling Point: 68 °C at 760 mmHg
• Flash Point: -15 °C
• Appearance: Colourless to light yellow liquid
• Density: 0.807 g/cm³
• Vapor Pressure: 142mmHg at 25°C
• Refractive Index: 1.384
• Water Solubility: 6 g/100 mL (20℃)
• CAS DataBase Reference: 2-Methylacrolein(CAS DataBase Reference)
• NIST Chemistry Reference: 2-Methylacrolein(78-85-3)
• EPA Substance Registry System: 2-Methylacrolein(78-85-3)

Safety Data

• Hazard Codes: F:Flammable;;
• Statements: R11:; R24/25:; R26:; R34:
• Safety Statements: S16:; S26:; S28A:; S36/37/39:; S45:
• RIDADR: 2396
• HazardClass: 3
• PackingGroup: II
• Hazardous Substances Data: 78-85-3(Hazardous Substances Data)

Usage

General Description

2-Methylacrolein, also known as 2-methyl-2-propenal, is a chemical compound with the molecular formula C4H6O. It is a colorless to light yellow liquid with a pungent odor, and is highly flammable. 2-Methylacrolein is commonly used as a flavoring agent in food and beverages, and as a fragrance ingredient in perfumes and cosmetic products. It is also used in the synthesis of various organic compounds and as a reagent in chemical reactions. However, exposure to 2-Methylacrolein can cause irritation to the respiratory system, skin, and eyes, and prolonged or high-level exposure may lead to more serious health effects. Therefore, proper handling and storage of this chemical is essential to minimize the risk of adverse health effects.

InChI:InChI=1/C4H6O/c1-4(2)3-5/h3H,1H2,2H3

Synthetic route

formaldehyd (50-00-0) + propionaldehyde (123-38-6) → 2-methylpropenal (78-85-3)

Conditions	Yield
With acetic acid; dimethyl amine at 170 - 180℃; under 52505.3 Torr; for 0.00277778h; Flow reactor;	98.1%
With secondary amine salt In water at 15 - 44℃; for 1h;	96.6%
With L-proline In water at 42.84℃; for 0.5h; Kinetics; Mechanism; Reagent/catalyst; Temperature; Green chemistry;	91.1%

3-hydroxy-2-methyl-1-propene (513-42-8) → 2-methylpropenal (78-85-3)

Conditions	Yield
With aluminum oxide; pyridinium chlorochromate In hexane for 0.2h; Ambient temperature;	98%
With manganese(IV) oxide In diethyl ether Oxidation;	76%
at 500℃; beim Leiten ueber Messing;

poly(methacrylic acid) (79-41-4) → 2-methylpropenal (78-85-3)

Conditions	Yield
With thexylbromoborane dimethyl sulfide complex In carbon disulfide; dichloromethane at -20 - 20℃; for 1h;	94%

tert-butyl alcohol (75-65-0) → 2-methylpropenal (78-85-3)

Conditions	Yield
With oxygen In water at 350℃; under 750.075 Torr;	91.1%
With air; cobalt molybdenum at 319.9 - 379.9℃; Rate constant; Product distribution;	88.1%
With silicsa-alumina supported Mo12Bi1.7Fe2.0Co6.75Ni1.0Cs0.2Ox In water at 345℃; for 200h; Temperature; Inert atmosphere;	81.07%

((2-methylallyloxy)methyl)benzene (5658-46-8) → 2-methylpropenal (78-85-3)

Conditions	Yield
With water; iodine In 1,4-dioxane for 24h; Reflux;	91%

isobutene (115-11-7) → 2-methylpropenal (78-85-3)

Conditions	Yield
With oxygen; Bi-Mo oxide (1/1) at 400℃; Rate constant; Kinetics; also without O2; other temperature;	90%
With oxygen; Mo-Bi-Fe-Co-Ni-K based mixed metal oxide In water at 340 - 360℃; under 760.051 Torr; for 100h;	89.9%
With Mo12Bi0.5Fe2.4Co7.2Zn1.1Sb0.7Si7W0.3K0.5O(x); water; oxygen at 340℃; for 0.001h; Sealed tube; Inert atmosphere;	88.8%

1-butylene (106-98-9) + isobutene (115-11-7) → 2-methylpropenal (78-85-3) + buta-1,3-diene (106-99-0)

Conditions	Yield
With nitrogen; Mo12Co5.7Fe3.8Bi0.5Ce0.1Tl0.3Sb0.5O49.1; water; oxygen at 380℃; for 10005h; Reagent/catalyst;	A 65% B 89%

isobutene (115-11-7) → 2-methylpropenal (78-85-3) + carbon dioxide (124-38-9) + carbon monoxide (201230-82-2)

Conditions	Yield
With air; pelleted Fe-Te-Mo-O at 430℃; Yields of byproduct given;	A 83.8% B n/a C n/a
With air; pelleted Fe-Te-Mo-O at 430℃; Product distribution; further temperatures: 370, 400 deg C; effect of various catalyst supports investigated;	A 83.8% B n/a C n/a
With oxygen multicomponent oxide catalyst(Co, Mo, Bi, Sb, Fe, K);

isobutyraldehyde (78-84-2) → 2-methylpropenal (78-85-3)

Conditions	Yield
With dipotassium peroxodisulfate; palladium diacetate; trifluoroacetic acid; 3-amino propanoic acid In acetonitrile at 60℃; for 24h; Sealed tube;	82%
With oxygen; C4H8N3O2Pb(1+)*CF3O3S(1-) In various solvent(s) under 760 Torr; Ambient temperature; Yield given;
at 400℃; Dehydrierung an einem Cu-Cr-Zn-Cd-Oxydkatalysator;

tert-butyl alcohol (75-65-0) → 2-methylpropenal (78-85-3) + poly(methacrylic acid) (79-41-4) + isobutene (115-11-7)

Conditions	Yield
With oxygen; silica-alumina In water at 355℃; Product distribution / selectivity;	A 78.4% B 1.9% C 1.1%
With oxygen; silica-alumina In water at 355℃; Product distribution / selectivity;	A 78.1% B 2.2% C 1%
With oxygen; 5% Pd/zirconia In water at 130℃; under 36003.6 Torr; Product distribution / selectivity; autoclave;
With oxygen; palladium on silica gel In water at 130℃; under 36003.6 Torr; Product distribution / selectivity; autoclave;

isobutene (115-11-7) → 2-methylpropenal (78-85-3) + ethanol (64-17-5) + acetone (67-64-1) + acetonitrile (75-05-8) + propiononitrile (107-12-0) + methacrylonitrile (126-98-7)

Conditions	Yield
With nitrogen(II) oxide; nickel(II) oxide; aluminum oxide at 410℃; Product distribution; var. cat.: pure NiO, NiO supported by alumina, silica, magnesia, alumina-magnesia, silica-alumina, silica-magnesia; var. temp.;	A 4.5% B 2% C 2.5% D 7.5% E 2% F 76%

isobutene (115-11-7) → 2-methylpropenal (78-85-3) + acetone (67-64-1) + acetonitrile (75-05-8) + methacrylonitrile (126-98-7)

Conditions	Yield
With nitrogen(II) oxide; nickel(II) oxide; aluminum oxide at 410℃; var. cat. and temp.;	A 4.5% B 2.5% C 7.5% D 76%

isobutene (115-11-7) → 2-methylpropenal (78-85-3) + poly(methacrylic acid) (79-41-4) + acetic acid (64-19-7)

Conditions	Yield
With air; water; CoMoTeO at 425℃;	A 68.2% B 9% C 1%
With air; V-Mo-Te-O at 405℃;	A 59% B 6% C 3%
With air; water; CoMoTeO at 375℃; Product distribution; Thermodynamic data; direct catalytic oxidation; varying: temperatures: 300 to 450 deg C; reactant composition;	A 27.5% B 39.5% C 4%

tert-butyl alcohol (75-65-0) → 2-methylpropenal (78-85-3) + isobutene (115-11-7)

Conditions	Yield
With air; iron-tellurium-molybdenum-oxide at 419.85℃; for 0.000916667h; Product distribution; Further Variations:; Temperatures; Catalysts; time of contact; Oxidation;	A 64.8% B n/a

isoprene (78-79-5) → formaldehyd (50-00-0) + 2-methylpropenal (78-85-3) + methyl vinyl ketone (78-94-4)

Conditions	Yield
With oxygen; ozone In gas Product distribution; gas-phase ozonolysis of alkenes; formation of OH radicals; use of CO as scavenger for OH radicals;	A 54% B 28% C 21%

formaldehyd (50-00-0) + propionaldehyde (123-38-6) → 2-methylpropenal (78-85-3) + 2-methyl-2-pentenal (14250-96-5, 16958-22-8, 623-36-9)

Conditions	Yield
With aniline hydrochloride In N,N-dimethyl acetamide at 125℃; for 3h; Autoclave;	A 30% B 17%

isobutene (115-11-7) → 2-methylpropenal (78-85-3) + poly(methacrylic acid) (79-41-4)

Conditions	Yield
With phosphoric acid; oxygen; 4-methoxy-phenol; palladium 10% on activated carbon In tert-butyl alcohol at 90℃; under 2250.23 - 30003 Torr; for 2h; Product distribution / selectivity; Heating / reflux;	A 24.6% B 9.2%
With oxygen; 4-methoxy-phenol; palladium 10% on activated carbon In tert-butyl alcohol at 90℃; under 2250.23 - 30003 Torr; for 2h; Product distribution / selectivity; Heating / reflux;	A 10.8% B 3.3%
With nitrogen; water; Mo12Bi1Fe1.5Co8Zn0.2Cs0.4Sb0.8Ox on graphite at 325 - 340℃; Conversion of starting material; Industry scale; Continuous process;

isoprene (78-79-5) → 3-methylfuran (930-27-8) + 2-methylpropenal (78-85-3) + methyl vinyl ketone (78-94-4) + 1-hydroxy-3-methylbut-3-en-2-one

Conditions	Yield
With air; dihydrogen peroxide for 0.5h; Product distribution; Kinetics; Further Variations:; Reagents; Oxidation; UV-irradiation;	A 2.8% B 19.1% C 20.5% D 3.7%

Isobutane (75-28-5) → 2-methylpropenal (78-85-3) + acetic acid (64-19-7)

Conditions	Yield
With oxygen; Mo1.0V0.3Nb0.1On at 350℃; under 760.051 Torr; Product distribution / selectivity; Gas phase;	A 0.2% B 18%
With oxygen; Mo1.0V0.3Sb0.7Nb0.1On at 430℃; under 760.051 Torr; Product distribution / selectivity; Gas phase;	A 2.3% B 0.1%
With oxygen; Mo1.0V0.3Te0.16Nb0.1On at 430℃; under 760.051 Torr; Product distribution / selectivity; Gas phase;	A 1.4% B 0.1%

Isobutane (75-28-5) → 2-methylpropenal (78-85-3) + poly(methacrylic acid) (79-41-4) + isobutene (115-11-7)

Conditions	Yield
With oxygen; Mo1.0Sb0.5Ce0.09Sn0005Ag0001On at 525℃; under 760.051 Torr; Product distribution / selectivity; Gas phase;	A 11.5% B 0.3% C 4.2%
With oxygen; Mo1.0Sb0.5Ce0.09Ag0003On at 500℃; under 760.051 Torr; Product distribution / selectivity; Gas phase;	A 9.8% B 0.5% C 1.2%
With oxygen; Mo1.0Sb0.5Ce0.1On at 500℃; under 760.051 Torr; Product distribution / selectivity; Gas phase;	A 8.9% B 0.3% C 0.9%
With oxygen; Mo1.0Sb0.5Bi0.1Sn0.01On at 500℃; under 760.051 Torr; Product distribution / selectivity; Gas phase;	A 8.2% B 0.3% C 5.1%
With oxygen; MoV0.3Te0.23P0.3 at 400℃; Product distribution; Further Variations:; Temperatures; Catalysts;	A 3.4 % Chromat. B 3.6 % Chromat. C 6.4 % Chromat.

Isobutane (75-28-5) → 2-methylpropenal (78-85-3) + poly(methacrylic acid) (79-41-4) + acetic acid (64-19-7)

Conditions	Yield
With oxygen; Mo1.0V0.3Te0.16Nb0.2On at 390℃; under 760.051 Torr; Product distribution / selectivity; Gas phase;	A 1.9% B 0.4% C 1.8%
With oxygen; 2.5Cs(1+)*0.34H(1+)*0.08Ni(2+)*PMo12O40(3-)=Cs2.5H0.34Ni0.08PMo12O40 at 340℃; Product distribution; var. conc. of Cs in catalyst, effect of var. transition metals;
With Mo12O40P; oxygen at 623℃; other catalysts;
With Mo11O40PV(4-)*2.5H4N(1+)*H(1+)*0.5Cs(1+); oxygen at 340℃; under 760.051 Torr; for 18h;

isoprene (78-79-5) → 2-methylpropenal (78-85-3) + methyl vinyl ketone (78-94-4)

Conditions	Yield
With oxygen; bis(ethylene)rhodium acetylacetonate In toluene at 80℃; under 37503 Torr; for 1h;	A 1% B 1.3%
With oxygen; bis(ethylene)rhodium acetylacetonate In toluene at 80℃; under 37503 Torr; for 1h;	A 1% B 1.3%
With ozone at 24.9℃; under 760 Torr; Rate constant; Thermodynamic data; other temperatures (240-324 K), Arrhenius parameters;	A 35 % Chromat. B 18 % Chromat.
With dinitrogen pentoxide at 296℃; under 740 Torr; Mechanism; mechanism of the reaction with NO3 radical;

dihydro-4-methylfuran-2,3-dione (33972-94-0) → 2-methylpropenal (78-85-3)

Conditions	Yield
at 300℃; Erhitzen im Stickstoff-Strom;
at 280 - 300℃;

2,5-dimethyl-3,4-dihydro-2H-pyran-2-carbaldehyde (1920-21-4) → 2-methylpropenal (78-85-3)

Conditions	Yield
at 450℃;

2-methylpropane-1,2,3-triol (25245-58-3) → 2-methylpropenal (78-85-3)

Conditions	Yield
With sulfuric acid
With sulfuric acid

1,1-diethoxy-2-methyl-2-propene (23553-27-7) → 2-methylpropenal (78-85-3)

Conditions	Yield
With sulfuric acid
With tartaric acid
With sulfuric acid

3-chloro-2-methylpropenol (76539-14-5) → 2-methylpropenal (78-85-3)

Conditions	Yield
With sulfuric acid; isobutyric Acid
With sulfuric acid

2-methyl-2-propene-1-al oxime (28051-68-5, 73502-59-7, 72589-84-5) → 2-methylpropenal (78-85-3)

Conditions	Yield
With acetic acid; sodium nitrite at 60 - 70℃;

2-methylpropenal (78-85-3) + methyl 2-methoxy-6-hydroxy-7,8-dihydro-5-quinolinecarboxylate (120686-00-2) → (+/-)-7,8,9,10-tetrahydro-8-hydroxy-2-methoxy-7-methyl-11-oxo-5,9-methanocycloocta[b]pyridine-5(6H)-carboxylic acid methyl ester (120686-01-3)

Conditions	Yield
With quinindine for 43h;	100%
N,N,N',N'-tetramethylguanidine In dichloromethane Ambient temperature;	93%

2-methylpropenal (78-85-3) + methylcopper (1184-53-8) → 2-Methylbutyraldehyde (96-17-3, 57456-98-1)

Conditions	Yield
With N,N,N,N,N,N-hexamethylphosphoric triamide; chloro-trimethyl-silane; lithium iodide In various solvent(s) at -78℃; for 1h;	100%

2-methylpropenal (78-85-3) + n-pentylcopper (64889-46-9) → 2-methyl-1-octanal (49642-49-1, 55352-42-6, 72598-55-1, 7786-29-0)

Conditions	Yield
With N,N,N,N,N,N-hexamethylphosphoric triamide; chloro-trimethyl-silane; lithium iodide In various solvent(s) at -78℃; for 0.1h;	100%

2-methylpropenal (78-85-3) + 4-(2-(S)-methoxymethyl-pyrrolidin-1-yl)-3-(tert-butyldimethylsiloxy)-1,3-butadiene (250696-15-2) → 4-(tert-butyl-dimethyl-silanyloxy)-2-(2-methoxymethyl-pyrrolidin-1-yl)-1-methyl-cyclohex-3-enecarbaldehyde

Conditions	Yield
In toluene Diels-Alder reaction; a) -20 deg C, 30 min, b) RT, 22 h;	100%

2-methylpropenal (78-85-3) + 4-[2,5-(R,R)-dimethoxymethyl-pyrrolidin-1-yl]-3-(tert-butyldimethylsiloxy)-1,3-butadiene → 2-((2R,5R)-2,5-Bis-methoxymethyl-pyrrolidin-1-yl)-4-(tert-butyl-dimethyl-silanyloxy)-1-methyl-cyclohex-3-enecarbaldehyde

Conditions	Yield
In toluene Diels-Alder reaction; a) -20 deg C, 30 min, b) RT, 22 h;	100%

2-methylpropenal (78-85-3) + bis(2-pyridyldimethylsilyl)methane (243468-48-6) → (E,E)-2-pyridyldimethyl(3-methylbuta-1,3-dienyl)silane (270589-04-3)

Conditions	Yield
Stage #1: bis(2-pyridyldimethylsilyl)methane With n-butyllithium In diethyl ether; hexane at -78℃; Metallation; Stage #2: 2-methylpropenal In diethyl ether; hexane at -78 - 20℃; Peterson-type olefination; Further stages.;	100%
Stage #1: bis(2-pyridyldimethylsilyl)methane With n-butyllithium In diethyl ether; hexane at -78℃; for 1h; Stage #2: 2-methylpropenal In diethyl ether; hexane at -78 - 20℃; for 1.5h; Peterson-type olefination;

2-methylpropenal (78-85-3) + (1R,4aR,8aS)-1,4a-Dimethyl-5-vinyl-1,2,3,4,4a,7,8,8a-octahydro-naphthalene-1-carboxylic acid methyl ester (287401-11-0) → (1R,4aR,10aS)-8-Formyl-1,4a,8-trimethyl-1,2,3,4,4a,6,7,8,8a,9,10,10a-dodecahydro-phenanthrene-1-carboxylic acid methyl ester (287401-12-1)

Conditions	Yield
at 25℃; for 8h; Diels-Alder cycloaddition;	100%
at 25℃; for 8h; Cycloaddition; Diels-Alder reaction;	100%
at 25℃; for 8h; Diels-Alder Reaction; Neat (no solvent);	100%

2-methylpropenal (78-85-3) + (E)-methyl benzyl(buta-1,3-dienyl)carbamate → N-benzyl-N-[(1S,6R)-6-formyl-6-methyl-2-cyclohexen-1-yl]carbamic acid methyl ester (420838-62-6)

Conditions	Yield
With 4 A molecular sieve; TBDMS-substituted (1R,2R)-salen-Co(III)-SbF6 In dichloromethane at 20℃; for 20h; Diels-Alder cycloaddition;	100%

2-methylpropenal (78-85-3) + 5-(4-methoxyphenyl)-2-phenyl-2H-tetrazole (20433-10-7) → 3-(4-methoxyphenyl)-5-methyl-1-phenyl-4,5-dihydro-1H-pyrazole-5-carbaldehyde

Conditions	Yield
In benzene for 2h; UV-irradiation;	100%

2-methylpropenal (78-85-3) + (1R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-one (464-49-3) → C14H22O2

Conditions	Yield
Stage #1: (1R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-one With n-butyllithium; diisopropylamine In tetrahydrofuran; hexane at 0℃; Stage #2: 2-methylpropenal In tetrahydrofuran; hexane at -78℃; Further stages.;	100%

methanol (67-56-1) + 2-methylpropenal (78-85-3) → methacrylic acid methyl ester (80-62-6)

Conditions	Yield
With 10H-phenothiazine; hydroquinone at 40℃; for 22h; Reagent/catalyst; Concentration; Inert atmosphere;	99%
With 1.5 % Au/alumina; oxygen at 60℃; under 9034.64 Torr; Catalytic behavior; chemoselective reaction;	99.7%
With oxygen at 69.84℃; under 1500.15 Torr; for 2h; Reagent/catalyst; Autoclave;	98%

2-methylpropenal (78-85-3) + triisopropylsilyl (E)-propylideneazinate → [(R)-3-ethyl-5-methyl-5-isoxazolinyl]methanol

Conditions

Yield

Stage #1: 2-methylpropenal; triisopropylsilyl (E)-propylideneazinate With trifluorormethanesulfonic acid; (S)-3,3-diphenyl-1-(o-tolyl)hexahydropyrrolo[1,2-c]-[1,3,2]oxazaborole In dichloromethane; toluene at -60℃; for 12h; Inert atmosphere; Schlenk technique; Stage #2: With sodium tetrahydroborate In methanol; dichloromethane; toluene at -60 - 20℃; Catalytic behavior; Reagent/catalyst; Solvent; enantioselective reaction;

99.7%

2-methylpropenal (78-85-3) + cyclopenta-1,3-diene (542-92-7) → endo-bicyclo[2.2.1]hept-5-ene-2-methyl-2-carboxaldehyde (34618-30-9, 34618-31-0, 40441-67-6, 72203-36-2, 72204-08-1, 112710-18-6, 116299-25-3, 126924-44-5, 142506-91-0)

Conditions	Yield
With C30H29B2Br6N2O6P In dichloromethane at -78℃; for 1h; Reagent/catalyst; Diels-Alder Cycloaddition; Schlenk technique; Inert atmosphere; Molecular sieve; enantioselective reaction;	99%
With [BCl2(1-methylimidazole)][Al2Cl7] In neat (no solvent) at 0℃; for 0.0833333h; Diels-Alder Cycloaddition; Inert atmosphere;	91%
In benzene at 20℃;
In benzene at 80℃;
With C35H56AlNO2S In chloroform-d1 at 20℃; for 1.5h; Reagent/catalyst; Diels-Alder Cycloaddition; Inert atmosphere; diastereoselective reaction;	27 %Spectr.

2-methylpropenal (78-85-3) + 2-methyl-2-(trimethylsilyloxy)-3-pentanone (72507-50-7) → (4R*,5R*)-5-hydroxy-2,4,6-trimethyl-2-<(trimethylsilyl)oxy>-6-hepten-3-one (100806-39-1)

Conditions	Yield
Stage #1: 2-methyl-2-(trimethylsilyloxy)-3-pentanone With lithium diisopropyl amide In tetrahydrofuran; hexane at -78℃; Inert atmosphere; Stage #2: 2-methylpropenal In tetrahydrofuran; hexane at -78℃; for 0.25h; Inert atmosphere;	99%
With lithium diisopropyl amide 1.) THF, hexane, -78 deg C, 25 min, 2.) from -78 deg C to RT; Yield given. Multistep reaction;

2-methylpropenal (78-85-3) + cyclopenta-1,3-diene (542-92-7) → (2R)-2-methylbicyclo[2.2.1]hept-5-ene-2-carbaldehyde (72203-36-2)

Conditions	Yield
With (R)-3,3'-bis(2-hydroxyphenyl)-2,2'-dihydroxy-1,1'-binaphthyl-boric acid In tetrahydrofuran; dichloromethane at -78℃; for 4h;	99%
With (R)-3,3'-di(2-hydroxyphenyl)-2,2'-dihydroxy-1,1'-binaphthyl*B(OMe)3 In tetrahydrofuran; dichloromethane at -78℃; for 4h;	99%
With 2,6-di-tert-butyl-pyridine; boron tribromide; (2S,5S)-N-2-hydroxybenzyl-2,5-dibenzylpyrrolidine In dichloromethane at -94℃; for 1h; Diels-Alder reaction;	96%

2-methylpropenal (78-85-3) + ethyl acetate (141-78-6) → Ethyl (+/-)-3-hydroxy-4-methyl-4-pentenoate (122622-90-6)

Conditions	Yield
Stage #1: ethyl acetate With lithium diisopropyl amide In tetrahydrofuran at -78℃; for 0.333333h; Stage #2: 2-methylpropenal In tetrahydrofuran at -78℃; for 1h;	99%
With lithium diisopropyl amide In tetrahydrofuran	91%
With lithium diisopropyl amide In tetrahydrofuran; hexane at -60 - -30℃; for 0.833333h;	91%

2-methylpropenal (78-85-3) + (E)-3-(tert-butyldimethylsiloxy)-1-(2-oxazolidinon-3-yl)-1,3-butadiene (300545-19-1) → 1-(tert-butyldimethylsilyloxy)-4-formyl-4-methyl-3-(2-oxazolidinon-3-yl)cyclohexene

Conditions	Yield
In toluene at 55℃; for 20h; Diels-Alder reaction;	99%
In chloroform-d1 at 22℃; Kinetics; Further Variations:; Solvents; temperature; Diels-Alder reaction;

2-methylpropenal (78-85-3) + cyclopenta-1,3-diene (542-92-7) → (1S,2S,4S)-2-Methylbicyclo<2.2.1>hept-5-en-2-carbaldehyd (142506-91-0)

Conditions	Yield
With C66H29B2F30N2O6P In dichloromethane at -78℃; for 1h; Reagent/catalyst; Diels-Alder Cycloaddition; Schlenk technique; Inert atmosphere; Molecular sieve; enantioselective reaction;	99%
silver hexafluoroantimonate; [η6-cymene)RuCl(L4)]SbF6 In dichloromethane at -24℃; for 16h;	95%

2-methylpropenal (78-85-3) + isoprene (78-79-5) → (S)-1,4-dimethylcyclohex-3-ene-1-carboxaldehyde

Conditions	Yield
(S)-oxazaborolidine-aluminum bromide at -78℃; for 16h; Diels-Alder reaction;	99%
With trifluorormethanesulfonic acid; chiral oxazaborolidine In dichloromethane at -78℃; for 13h; Diels-Alder reaction;	96%
With aluminum tri-bromide; C24H22BF2NO In methanol at -10℃; Reagent/catalyst; Temperature; Diels-Alder Cycloaddition; enantioselective reaction;	n/a

2-methylpropenal (78-85-3) + [Ru(η5-C5H5)((S,S)-BIPHOP-F)(acetone)][SbF6] → Ru(OCHC(CH3)CH2)(C5H5)(C38H12F20O2P2)(1+)*SbF6(1-) = [Ru(OCHC(CH3)CH2)(C5H5)(C38H12F20O2P2)]SbF6

Conditions	Yield
In dichloromethane stirring (5 min); removal of volatiles (vac.);	99%

2-methylpropenal (78-85-3) + [(hydrotris(pyrazolyl)borate)Ru(S,S-1,2-bis(diphenylphosphinoamino)cyclohexane)]2(μ-N2)[PF6]2 → [(hydrotris(pyrazolyl)borate)(methacrolein)Ru(S,S-1,2-bis(diphenylphosphinoamino)cyclohexane)][PF6]

Conditions	Yield
In neat (no solvent) under dry N2 or Ar, using Schlenk techniques; excess neat methacrolein; pptd. with petroleum ether;	99%

2-methylpropenal (78-85-3) + [(hydrotris(pyrazolyl)borate)Ru(R,R-1,2-bis(diphenylphosphinoamino)cyclohexane)]2(μ-N2)[PF6]2 → [(hydrotris(pyrazolyl)borate)(methacrolein)Ru(R,R-1,2-bis(diphenylphosphinoamino)cyclohexane)][PF6]

Conditions	Yield
In neat (no solvent) under dry N2 or Ar, using Schlenk techniques; excess neat methacrolein; pptd. with petroleum ether;	99%

2-methylpropenal (78-85-3) + (S(Ir)R(C))-[(η5-pentamethylcyclopentadienyl)Ir(cyphos)(H2O)](SbF6)2 → (S(Ir)R(C))-[(η5-pentamethylcyclopentadienyl)Ir(cyphos)(methacrolein)](SbF6)2

Conditions	Yield
With molecular sieves In dichloromethane byproducts: water; (Ar); addn. of an excess of methacrolein and molecular sieves to soln. of (S(Ir)R(C))-(η5-C5Me5)Ir(cyphos)(H2O)(SbF6)2 in CH2Cl2 at -25°C, stirring for 20 min; filtration through a cannula, concn., addn. of n-hexane, filtration, washing with n-hexane, vac.-drying; elem. anal.;	99%

2-methylpropenal (78-85-3) + Dimethylphenylsilane (766-77-8) → [((E)-But-1-enyl)oxy]-dimethyl-phenyl-silane

Conditions	Yield
With bis(1,5-cyclooctadiene)dichloro[1,3-bis(1′-butylbenzimidazol-2′-yliden-3′-yl)benzene]dirhodium(I) In benzene-d6 at 20℃; for 20h; Catalytic behavior; Time; Reagent/catalyst;	99%

2-methylpropenal (78-85-3) → isobutyraldehyde (78-84-2)

Conditions	Yield
With hydrogen In acetone at 20℃; under 760.051 Torr; for 0.25h; chemoselective reaction;	99%
With hydrogen; sodium triethylborohydride In tetrahydrofuran at 23℃; under 30402 Torr; for 72h; Catalytic behavior; Inert atmosphere; Schlenk technique;	76%
With hydrogen In ethyl acetate at 20℃; under 760.051 Torr; for 0.25h; chemoselective reaction;

2-methylpropenal (78-85-3) → 2,3-dibromo-2-methylpropanal (33673-73-3)

Conditions	Yield
With bromine In dichloromethane at 20℃; for 2.5h;	98%
With bromine at 50℃; for 2h;	60%
With carbon disulfide; bromine
With bromine
With bromine In dichloromethane at 10℃;

2-methylpropenal (78-85-3) → 2-methyl-2,3-dichloropropionaldehyde (10141-22-7)

Conditions	Yield
With chlorine at -5 - 0℃; for 1.5h; Neat (no solvent);	98%
With chlorine at 50℃; for 2h;	76%
With chlorine
With chlorine

2-methylpropenal (78-85-3) + cyclopenta-1,3-diene (542-92-7) → exo-2-methylbicyclo[2.2.1]hept-5-ene-2-carbaldehyde (34618-30-9, 34618-31-0, 40441-67-6, 72203-36-2, 72204-08-1, 112710-18-6, 116299-25-3, 126924-44-5, 142506-91-0)

Conditions	Yield
With C31H28BNO; tin(IV) chloride In dichloromethane at -78℃; for 2h; Reagent/catalyst; Diels-Alder Cycloaddition; Reflux; stereoselective reaction;	98%
With 2,2'-bis(dibenzo[a,c]-1,3,2-dioxaborepin-2-yloxy)biphenyl In dichloromethane at -78℃; for 24h; Diels-Alder reaction;	97%
With bis<2-(4,4-dimethyl-4,5-dihydrooxazol-2-yl)phenolato-N,O>-zirconium(IV) triflate In dichloromethane at -78 - 20℃;	75%

Upstream product

• 33972-94-0 dihydro-4-methylfuran-2,3-dione 
• 25245-58-3 2-methylpropane-1,2,3-triol 
• 76539-14-5 3-chloro-2-methylpropenol 
• 28051-68-5 2-methyl-2-propene-1-al oxime 
• 597-32-0 1,3-dichloro-2-methyl-propan-2-ol 
• 597-33-1 3-chloro-2-methyl-propane-1,2-diol 
• 513-37-1 2-methylprop-1-enyl chloride 
• 628-56-8 isopropenylmethyl ether 
• 50-00-0 formaldehyd 
• 123-38-6 propionaldehyde 
• 115-11-7 isobutene 
• 75-18-3 dimethylsulfide 
• 98909-23-0 (Hydroxymethyl)(1-methoxy-2-methyl-2-propenyl)peroxid 
• 98909-21-8 (1-Methoxy-2-methyl-2-propenyl)hydroperoxid 

Downstream Products

• 100518-52-3 2-methyl-5-phenylpent-1-en-4-yn-3-ol 
• 13019-19-7 2-methylhept-1-en-3-ol 
• 10476-95-6 methallylidene diacetate 
• 20668-26-2 3,6-dimethylquinoline 
• 931-96-4 1-methyl-3-cyclohexene-1-carboxaldehyde 
• 19212-60-3 4-methyl-1-phenyl-4,5-dihydro-1H-pyrazole 
• 99067-85-3 methacrolein phenylhydrazone 
• 100048-23-5 2-isopropoxymethyl-2,4-dimethyl-glutaraldehyde 
• 41496-43-9 2-methyl-3-(4-methylphenyl)propanal 
• 26334-42-9 3,4-dihydro-2-methyl-2H-pyran-2-carboxaldehyde 
• 20668-29-5 3,8-dimethylquinoline 
• 100315-39-7 2-methallyloxymethyl-2,4-dimethyl-glutaraldehyde 
• 17123-60-3 2-methylhexa-1,5-dien-3-ol 
• 20728-03-4 α-methylbicyclo[2.2.1]heptane-2-propionaldehyde 

Relevant articles and documents

Supported Rb- or Cs-containing HPA catalysts for the selective oxidation of isobutane

Silica-supported catalysts based on Keggin-type heteropolyacids (HPAs) containing rubidium or cesium as counter cations have been prepared by the impregnation method and evaluated in the selective oxidation of isobutane to methacrolein and methacrylic acid. The catalysts were characterized by various techniques such as XRD, N2 physisorption, TGA, Raman spectroscopy, H2-TPR, and NH3-TPD in order to study their thermal stability, structural, and textural properties, acidity and reducibility. It was evidenced that the reducibility of the Keggin type HPAs was improved by supporting the active phase on SiO2. A loading of 40 wt% was the optimum for the selective oxidation of isobutane (IBAN) to methacrylic acid (MAA). The selectivities to MAA and methacrolein (MAC) at given conversion were increased when Cs+ was used as counter cation compared to Rb+. The same trend was observed for mono- and di-vanado-substituted phosphomolybdic acid, whereby the performance followed the order: CsV1/SiO2 > RbV1/SiO2 > CsV2/SiO2 > RbV2/SiO2. The density of acid sites was correlated to the catalytic activity, which underlines the importance of the acid sites for alkane activation.

IMPROVED SAFE METHOD FOR TANDEM C-4 OXIDATION TO METHACRYLIC ACID

The present invention relates to an improved process for the production of methacrylates, in particular methacrylic acid and/or methyl methacrylate (MMA). Furthermore, the present invention relates to a process and specific embodiments of this process for the safe and efficient production of these products from C-4-based raw materials, in particular those based on isobutylene or tert-butanol as raw materials. With this novel process, it is possible to operate such processes for a longer period of time without any safety or cleaning related shutdowns. This makes it possible to carry out such processes as simple, economic and environmentally friendly as possible.

Catalytic synthesis of methacrolein: Via the condensation of formaldehyde and propionaldehyde with l-proline

Methacrolein (MAL) is an important chemical for the manufacture of methyl methacrylate and a key monomer in many polymerization reactions. In this study, l-proline was investigated as the catalyst for the aldol condensation of formaldehyde and propionaldehyde to produce MAL. The catalytic activity of the reaction system was closely related to the competition between the main reaction synthesizing MAL and the side reaction producing 2-methyl-2-pentenal, which could be modified by adjusting the operating parameters. The influences of several operating conditions, including temperature, reaction time and water content, on the catalytic performance of the system were systematically studied via a series of single-factor experiments, and the optimized reaction conditions were obtained. The mechanistic investigation via ESI-MS indicated that the reaction pathway followed the Mannich route. Experimental and theoretical kinetic analyses of the l-proline-catalyzed aldol condensation reaction were performed, and the reaction orders of the reactants were obtained by regression. The results showed that l-proline was an efficient catalyst for the production of MAL via aldol condensation under mild conditions.