2-(methyl thio) methyl-2-butenal

2-(methyl thio) methyl-2-butenal is a sulfur-containing aliphatic aldehyde characterized chemically by the molecular formula C₆H₁₀OS. It appears as a liquid and exhibits a pronounced sulfurous odor reminiscent of cooked cabbage, burnt matches, roasted onion, and a distinct onion note. The compound is also known by multiple synonyms including 2-(methylsulfanylmethyl)but-2-enal and 2-ethylidene methional, reflecting variations in nomenclature across chemical databases. It is linked to controlled-vocabulary identifiers such as PubChem CID 62912, enabling detailed chemical profile access. Derivation typically involves synthetic or natural pathways contributing to its presence in roasted coffee and other food products. The compound's sensory and physicochemical attributes render it valuable for inclusion in flavor formulations, particularly to impart sulfurous and savory notes.

This compound occurs naturally in roasted coffee where it contributes to characteristic aroma profiles. It is applied predominantly as a flavoring agent to provide onion and roasted savory notes in various food items. Regulatory evaluation by bodies such as FEMA (US) categorizes it with FEMA number 3601, recognizing its use in food flavorings under defined conditions. Its functional application extends broadly within the flavor industry to replicate or enhance sulfurous nuances found in cooked vegetables and roasted products. Owing to its chemical structure, it is not intended for fragrance use but primarily for controlled flavoring in foodstuffs. Its inclusion in formulations must comply with maximum usage levels established by food safety authorities, ensuring sensory impact without exceeding safety thresholds.

2-(methyl thio) methyl-2-butenal exhibits a moderate molecular weight of 130.21 g/mol and demonstrates physicochemical characteristics that influence its behavior in formulations. The compound's specific gravity ranges between 0.982 and 0.987 at 25 °C, and its refractive index is reported between 1.5228 and 1.5328 at 20 °C. It has a low vapor pressure of 0.09 mmHg at 25 °C, indicating limited volatility under ambient conditions. Its log P (octanol-water partition coefficient) is approximately 1.368, denoting moderate lipophilicity which favors solubility in fats and oils while showing partial solubility in water. Its flash point is about 213 °F (approximately 100 °C), a factor to consider in handling and storage. The compound's sulfurous odor and reactivity derive from its alpha,beta-unsaturated aldehyde and methylthio functional groups, which also affect stability and interaction within flavor systems.

(IUPAC):	Atomic Weights of the Elements 2011 (pdf)
Videos:	The Periodic Table of Videos
tgsc:	Atomic Weights use for this web site
(IUPAC):	Periodic Table of the Elements
FDA Substances Added to Food (formerly EAFUS):	View
HMDB (The Human Metabolome Database):	HMDB31370
FooDB:	FDB003437
YMDB (Yeast Metabolome Database):	YMDB01485
VCF-Online:	VCF Volatile Compounds in Food
ChemSpider:	View
FAO:	2-(Methylthio)methyl-2-butenal

Safety information

Hazards identification
Classification of the substance or mixture
GHS Classification in accordance with 29 CFR 1910 (OSHA HCS)
None found.
GHS Label elements, including precautionary statements
Pictogram
Hazard statement(s)
None found.
Precautionary statement(s)
None found.
Oral/Parenteral Toxicity:
Not determined
Dermal Toxicity:
Not determined
Inhalation Toxicity:
Not determined

Safety in use information

Category:
flavoring agents
Recommendation for 2-(methyl thio) methyl-2-butenal usage levels up to:
	not for fragrance use.
Maximised Survey-derived Daily Intakes (MSDI-EU):		0.024 (μg/capita/day)
Maximised Survey-derived Daily Intakes (MSDI-USA):		0.10 (μg/capita/day)
Modified Theoretical Added Maximum Daily Intake (mTAMDI):		280 (μg/person/day)
Threshold of Concern:		90 (μg/person/day)
Structure Class:		III
Use levels for FEMA GRAS flavoring substances on which the FEMA Expert Panel based its judgments that the substances are generally recognized as safe (GRAS).
The Expert Panel also publishes separate extensive reviews of scientific information on all FEMA GRAS flavoring substances and can be found at FEMA Flavor Ingredient Library
publication number: 12
Click here to view publication 12
		average usual ppm	average maximum ppm
baked goods:		-	-
beverages(nonalcoholic):		-	-
beverages(alcoholic):		-	-
breakfast cereal:		-	-
cheese:		-	-
chewing gum:		-	-
condiments / relishes:		-	-
confectionery froastings:		-	-
egg products:		-	-
fats / oils:		-	-
fish products:		-	-
frozen dairy:		-	-
fruit ices:		-	-
gelatins / puddings:		-	-
granulated sugar:		-	-
gravies:		-	0.50000
hard candy:		-	-
imitation dairy:		-	-
instant coffee / tea:		-	-
jams / jellies:		-	-
meat products:		-	-
milk products:		-	-
nut products:		-	-
other grains:		-	-
poultry:		-	-
processed fruits:		-	-
processed vegetables:		-	-
reconstituted vegetables:		-	1.00000
seasonings / flavors:		-	-
snack foods:		-	1.00000
soft candy:		-	-
soups:		-	0.50000
sugar substitutes:		-	-
sweet sauces:		-	-
Food categories according to Commission Regulation EC No. 1565/2000 (EC, 2000) in FGE.06 (EFSA, 2002a). According to the Industry the "normal" use is defined as the average of reported usages and "maximum use" is defined as the 95th percentile of reported usages (EFSA, 2002i).
Note: mg/kg = 0.001/1000 = 0.000001 = 1/1000000 = ppm.
		average usage mg/kg	maximum usage mg/kg
Dairy products, excluding products of category 02.0 (01.0):		0.35000	1.00000
Fats and oils, and fat emulsions (type water-in-oil) (02.0):		0.04000	0.40000
Edible ices, including sherbet and sorbet (03.0):		0.50000	2.00000
Processed fruit (04.1):		0.20000	-
Processed vegetables (incl. mushrooms & fungi, roots & tubers, pulses and legumes), and nuts & seeds (04.2):		0.20000	0.50000
Confectionery (05.0):		0.50000	1.00000
Chewing gum (05.3):		1.00000	-
Cereals and cereal products, incl. flours & starches from roots & tubers, pulses & legumes, excluding bakery (06.0):		0.61000	1.00000
Bakery wares (07.0):		0.73000	1.10000
Meat and meat products, including poultry and game (08.0):		0.55000	3.32000
Fish and fish products, including molluscs, crustaceans and echinoderms (MCE) (09.0):		0.06000	0.10000
Eggs and egg products (10.0):		-	-
Sweeteners, including honey (11.0):		-	-
Salts, spices, soups, sauces, salads, protein products, etc. (12.0):		0.15000	1.00000
Foodstuffs intended for particular nutritional uses (13.0):		-	-
Non-alcoholic ("soft") beverages, excl. dairy products (14.1):		0.50000	1.00000
Alcoholic beverages, incl. alcohol-free and low-alcoholic counterparts (14.2):		0.15000	0.50000
Ready-to-eat savouries (15.0):		0.10000	0.28000
Composite foods (e.g. casseroles, meat pies, mincemeat) - foods that could not be placed in categories 01.0 - 15.0 (16.0):		0.35000	1.00000

Safety references

European Food Safety Athority(EFSA):Flavor usage levels; Subacute, Subchronic, Chronic and Carcinogenicity Studies; Developmental / Reproductive Toxicity Studies; Genotoxicity Studies...

European Food Safety Authority (EFSA) reference(s):

Scientific Opinion on Flavouring Group Evaluation 201 Revision 2 (FGE.201Rev2): 2-alkylated, aliphatic, acyclic alpha,beta-unsaturated aldehydes and precursors, with or without additional double-bonds, from chemical subgroup 1.1.2 of FGE.19 View page or View pdf

Scientific Opinion on Flavouring Group Evaluation 91, Revision 3 (FGE.91Rev3): consideration of aliphatic, aromatic and a,ß-unsaturated sulfides and thiols evaluated by JECFA (53rd, 61st, 68th and 76th meetings), structurally related to substances in FGE.08Rev5 View page or View pdf

EPI System: View

AIDS Citations:Search

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Toxicology Citations:Search

EPA ACToR:Toxicology Data

EPA Substance Registry Services (SRS):Registry

Laboratory Chemical Safety Summary :62912

National Institute of Allergy and Infectious Diseases:Data

WGK Germany:3

2-(methylsulfanylmethyl)but-2-enal

Chemidplus:0040878726

(E)-2-(methylsulfanylmethyl)but-2-enal

(Z)-2-(methylsulfanylmethyl)but-2-enal