Introduction
4-Methylcyclohexane-1,3-diamine, also known as 1,3-bis(aminomethyl)-4-methylcyclohexane, is an organic compound with the chemical formula C7H16N2. It is classified as an aliphatic diamine, featuring two amine groups (NH2) attached to a cyclohexane ring. The compound appears as a colorless to light yellow liquid and possesses a distinctive molecular structure characterized by a methyl group at the 4th position of the cyclohexane ring and amine groups at the 1st and 3rd carbons. This arrangement contributes to its unique chemical properties, including rigidity from the cyclohexane ring and reactivity from the amine groups
1. Safety and Hazards
HTDA is classified as a hazardous material due to its corrosive nature. It can cause severe skin burns and eye damage upon contact []. Inhalation of HTDA vapors can irritate the respiratory tract.
- Acute Toxicity:LD50 (oral, rat) = 1030 mg/kg []
- Skin Corrosion/Irritation:Skin Corrosive (Category 1B) []
- Serious Eye Damage/Eye Irritation:Serious Eye Damage (Category 1) []
2. Chemical Reactions
Typical of primary amines. Notably, it can react with polyisocyanates to form cross-linked polyurethane materials. The simplified reaction can be represented as follows:
O C N R N C O+H2N CH2 CH CH3 CH2 CH2 NH2→ cross linked polyurethane O C N R N C O+H2N CH2 CH CH3 CH2 CH2 NH2→ cross linked polyurethane
Here, R represents an aliphatic chain. Additionally, it can undergo complexation with metal ions and participate in various substitution reactions.
3. Synthesis Methods
The synthesis of 4-methylcyclohexane-1,3-diamine primarily involves the hydrogenation of dinitrotoluene isomers. This process entails reacting dinitrotoluene with hydrogen gas in the presence of a catalyst, converting nitro groups (NO2) into amine groups (NH2). This method not only yields the desired diamine but also allows for the production of high-purity compounds suitable for industrial applications.
4. Applications
The primary application of 4-methylcyclohexane-1,3-diamine is as a curing agent and cross-linker in the manufacture of polyurethanes. Its unique molecular structure allows it to enhance mechanical properties and chemical resistance in polyurethane elastomers, coatings, adhesives, and sealants. Additional applications include:
5. Structural adhesives
6. Interaction Studies
Interaction studies of 4-methylcyclohexane-1,3-diamine focus on its reactivity with various functional groups in polymers and its role in forming cross-linked structures. It exhibits high reactivity towards polyesters and polyethers due to its amine groups, which facilitate bonding and enhance material properties.
1. Methylcyclohexane
Methylcyclohexane (cyclohexylmethane) is an organic compound with the molecular formula is CH3C6H11. Classified as saturated hydrocarbon, it is a colourless liquid with a faint odor.
Methylcyclohexane is used as a solvent. It is mainly converted in naphtha reformers to toluene.[4] A special use is in PF-1 priming fluid in cruise missiles to aid engine start-up when they run on special nonvolatile jet fuel like JP-10.[5] Methylcyclohexane is also used in some correction fluids (such as White-Out) as a solvent.
1. History
While researching hydrogenation of arenes with hydroiodic acid in 1876[6] as part of his doctoral dissertation[7], Felix Wreden [ru] first prepared the hydrocarbon from toluene. He determined its boiling point to be 97°C, its density at 20°C to by 0.76 g/cc and named it hexahydrotoluene.[8] It was soon identified in oil from Baku and obtained by other synthetic methods.[9]
2. Production and use
The primary use of 4-methylcyclohexane-1,3-diamine (HTDA) is as an amine based curing agent and cross linker in polyurethane manufacture, and as an intermediate in some specialty polymers.
Due to its unique molecular structure and characteristics, HTDA possesses high reactivity, low viscosity and good fluidity, it can react with polyesters, polyethers and other multifunctional compounds, enhance the mechanical properties, chemical properties, heat and wear resistance, and form high-performance polyurethane elastomers, polyurethane coatings, polyurethane sealants, polyurethane adhesives and other products.
Application scope of our product: structural adhesive; Floors, grouting, coatings, etc. in buildings; compound material; Laminated casting and packaging; Heavy duty protective coating.
Most methylcyclohexane is extracted from petroleum but it can be also produced by catalytic hydrogenation of toluene:
CH3C6H5 + 3 H2 → CH3C6H11
Methylcyclohexane, as a component of a mixture, is usually dehydrogenated to toluene, which increases the octane rating of gasoline.
It is also one of a host of substances in jet fuel surrogate blends, e.g., for Jet A fuel.
3. Solvent
Methylcyclohexane is used as an organic solvent, with properties similar to related saturated hydrocarbons such as heptane.[13] It is also a solvent in many types of correction fluids.
Methylcyclohexane is a monosubstituted cyclohexane because it has one branching via the attachment of one methyl group on one carbon of the cyclohexane ring. Like all cyclohexanes, it can interconvert rapidly between two chair conformers.
The lowest energy form of this monosubstituted methylcyclohexane occurs when the methyl group occupies an equatorial rather than an axial position. This equilibrium is embodied in the concept of A value. In the axial position, the methyl group experiences steric crowding (steric strain) because of the presence of axial hydrogen atoms on the same side of the ring (known as the 1,3-diaxial interactions). There are two such interactions, with each pairwise methyl/hydrogen combination contributing approximately 7.61 kJ/mol of strain energy. The equatorial conformation experiences no such interaction, and so it is the energetically favored conformation.
4. Flammability and toxicity
Methylcyclohexane is flammable.
Furthermore, it is considered “very toxic to aquatic life”.[14] Note, while methylcyclohexane is a substructure of 4-methylcyclohexanemethanol (MCHM), it is distinct in its physical, chemical, and biological (ecologic, metabolic, and toxicologic) properties.
2. Preparation Methods
Synthetic Routes and Reaction Conditions
4-Methylcyclohexane-1,3-diamine can be synthesized through several methods. One common method involves the reaction of cyclohexanone with methylamine, followed by reduction with hydrogen in the presence of a catalyst such as palladium on carbon. Another method involves the reaction of 4-methylcyclohexanone with ammonia, followed by hydrogenation.
Industrial Production Methods
In industrial settings, this compound is often produced using a continuous flow process. This involves the catalytic hydrogenation of 4-methylcyclohexanone in the presence of ammonia. The reaction is typically carried out at elevated temperatures and pressures to ensure high yield and purity of the product.
3. Chemical Reactions Analysis
1. Types of Reactions
4-Methylcyclohexane-1,3-diamine undergoes various chemical reactions, including:
Oxidation: It can be oxidized to form corresponding imines or nitriles.
Reduction: It can be reduced to form cyclohexylamines.
Substitution: It can undergo nucleophilic substitution reactions with halides to form substituted amines.
2. Common Reagents and Conditions
Oxidation: Common oxidizing agents include potassium permanganate and hydrogen peroxide.
Reduction: Hydrogen gas in the presence of a palladium catalyst is commonly used.
Substitution: Halides such as chloroform or bromoform are used in the presence of a base like sodium hydroxide.
3. Major Products Formed
Oxidation: Imines or nitriles.
Reduction: Cyclohexylamines.
Substitution: Substituted amines with various functional groups.
4. Scientific Research Applications
4-Methylcyclohexane-1,3-diamine has several applications in scientific research:
Chemistry: It is used as a building block in the synthesis of complex organic molecules.
Biology: It is used in the study of enzyme mechanisms and protein interactions.
Medicine: It is investigated for its potential use in drug development, particularly in the synthesis of pharmaceuticals with amine functionalities.
Industry: It is used in the production of polymers, resins, and coatings due to its ability to form stable amine linkages.
5. Mechanism of Action
The mechanism of action of 4-Methylcyclohexane-1,3-diamine involves its interaction with various molecular targets. In biological systems, it can act as a ligand for enzymes, altering their activity by binding to their active sites. In industrial applications, it acts as a cross-linking agent, forming stable bonds with other molecules to create polymers and resins.
6. Comparison with Similar Compounds
Similar Compounds
Cyclohexane-1,3-diamine: Lacks the methyl group, making it less sterically hindered.
4-Methylcyclohexane-1,2-diamine: Has amino groups at different positions, affecting its reactivity.
4-Methylcyclohexane-1,4-diamine: Different positioning of amino groups alters its chemical properties.
7. Uniqueness
4-Methylcyclohexane-1,3-diamine is unique due to the specific positioning of its methyl and amino groups, which confer distinct reactivity and stability. This makes it particularly useful in applications requiring precise chemical modifications and stable amine linkages.
4. N,n’-diaminopropyl-2-methylcyclohexane -1,3-diamine and n,n’-diaminopropyl-4-methylcyclohexane -1,3-diamine and the use thereof as curing agents for epoxy resins
Abstract
The present invention relates to the polyamines N,N’-diaminopropyl-2-methylcyclohexane-1,3-diamine and N,N’-diaminopropyl-4-methylcyclohexane-1,3-diamine or mixtures thereof, the use thereof as curing agents for epoxy resin, and a curable composition comprising epoxy resin and said polyamines. This curing agent, and the corresponding curable composition, cures rapidly even at low temperatures and has good dew resistance; it is therefore particularly suitable for floor coatings. The invention further relates to the curing of said composition and to the cured epoxy resin obtained by curing said composition.
Description
The present invention relates to the polyamines N, N’-diaminopropyl-2-methyl-cyclohexane-1, 3-diamine and N, N’-diaminopropyl-4-methyl-cyclohexane-1, 3-diamine or mixtures thereof, their use as a hardener for epoxy resin, and a curable composition comprising epoxy resin and these polyamines. The invention further relates to the curing of this composition and the cured epoxy resin obtained by curing this composition.
Epoxy resins are well known and, because of their toughness, flexibility, adhesion and chemical resistance, are used as surface coating materials, as adhesives and for molding and laminating, and for producing fiber reinforced composites.
An important application of epoxy resins is the surface coating and in particular the floor coating (flooring). Hardeners are needed for this purpose, which allow a fast curing, even at low temperatures. The coating should be able to be loaded as quickly as possible after application to the surface (accessibility of floor coatings), ie it should have a sufficiently high hardness (for example Shore D hardness). Also a high glass transition temperature of the coating, so that the coating remains stable at high use temperatures, is an important criterion. For a coating of surfaces exposed to moisture (for example, outdoor floor coatings), good early water resistance is also important.
Typical hardeners for epoxy resins are polyamines, which cause a polyaddition reaction (chain extension). High reactivity polyamines are generally added just prior to the desired cure. Such systems are therefore so-called two-component (2K) systems.
For floor coatings, in particular aliphatic and cycloaliphatic polyamines are used as hardeners for epoxy resins (Ullmann’s Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, Germany, 2012, Vol. 13, Epoxy Resins, H. Pham & M. Marks (online:
15/10/2005, DOI: 10.1002 / 14356007.a09_547.pub2)). In this case, aliphatic polyamines such as diethylenetriamine (DETA), hexamethylenediamine (HMD) or triethylenetetraamine (TETA), as a rule, a high reactivity and thus allow even at room temperature or moderately elevated temperature rapid curing. The cycloaliphatic polyamines, such as, for example, isophoronediamine (IPDA), bis (4-aminocyclohexyl) methane (PACM), 1,2-diaminocyclohexane (1,2-DACH), dimethyldicycane (DMDC), 4-methylcyclohexane-1,3 -diamine (4-MCDA), 2-methylcyclohexyl-1, 3-diamine (2-MCDA) or a mixture of 2-MCDA and 4-MCDA (MCDA), usually react a little slower, which usually also with associated with a longer pot life.
With Typically, epoxy resins cured with cycloaliphatic amines are characterized by comparatively good electrical, mechanical and thermal properties, in particular a comparatively high glass transition temperature (Tg). Although the curing of epoxy resins with 1,2-DACH allows high glass transition temperatures, the high volatility and toxicity (especially skin sensitization) make the use of this amine problematic. For example, US Pat. No. 4,321,354 provides a 1,2-DACH derivative substituted with aminoproyl groups as a hardener which is less volatile and toxic.
MCDA, which is also described for the curing of epoxy resins (EP-B 443344;
WO 201 1/032877), is far less volatile and toxic than 1,2-DACH.
It would be desirable to have an amine hardener for curing epoxies for floor coating applications that would cure aliphatic polyamines quickly, especially at low temperatures, such as room temperature or below, or at moderately elevated temperatures, such as 75 ° C, with good thermal properties (high glass transition temperature) of united cycloaliphatic polyamines. Such a hardener should also be usable in the low-temperature range in particular, since it enables rapid hardening in which a comparatively high hardness (for example Shore D hardness) is achieved as quickly as possible. In addition, it is desirable that such a hardener has good early water resistance.
The problem underlying the invention can therefore be considered to be the provision of such an amine hardener, suitable for curing epoxy resins, in particular for floor coating applications, which combines rapid curing even at low temperatures, good thermal and mechanical properties and good early water resistance.
Accordingly, the present invention relates to the provision of a polyamine selected from the group consisting of N, N’-diaminopropyl-2-methyl-cyclohexane-1,3-diamine (DAP-2-MCDA) and N, N’-diaminopropyl- 4-methyl-cyclohexane-1,3-diamine (DAP-4-MCDA). In a particular embodiment, the present invention relates to mixtures of these polyamines (DAP-MCDA).
Curing of epoxy resin with DAP-MCDA
DAP-MCDA from Example 1 and epoxy resin (bisphenol A diglycidyl ether, Epilox A19-03, Leuna, EEW: 184 g / mol) were mixed in a stoichiometric ratio in an agitator (1 min at 2000 rpm). Immediately following the mixing, DSC measurements (differential scanning calorimetry) and rheological investigations were carried out. For comparison, corresponding compositions with TETA (Akzo-Nobel) or MCDA (BASF,) were examined in the same way.
The DSC investigations of the curing reaction of DAP-MCDA or TETA or MCDA to determine onset temperature (To), maximum temperature (Tmax), exothermic energy (ΔΗ) and glass transition temperatures (Tg) were performed according to ASTM D 3418, the following Temperature profile was used: 0 ° C ^ 5K / min 180 ° C 30min 180 ° C 20K / min 0 ° C 20K / min 220 ° C. For the 2nd run the following temperature profile was used: 0 ° C ^ 20K / min 220 ° C. The Tg was determined at the 2nd run. The results are summarized in Table 1.
The rheological measurements for investigating the reactivity profile of the various amine hardeners (TETA, MCDA and DAP-MCDA) with the epoxy resin were carried out on a shear stress controlled plate-plate rheometer (MCR 301, Anton Paar) with a plate diameter of 15 mm and a gap distance of 0, 25 mm at different temperatures. The time was determined (pot life, as a measure of the period in which the reaction resin mass is manageable), which required the freshly prepared reaction resin mass to reach a viscosity of 10,000 mPa * s at a defined temperature.
The measurement was carried out in rotation on the above-mentioned rheometer at various temperatures (10 ° C, 23 ° C and 75 ° C, respectively). At the same time the initial viscosity (averaged over the period of 2 to 5 minutes after mixing the components) for the respective mixtures was determined at the respective temperatures. Finally, the gel times were determined. These measurements were performed oscillating on the above-mentioned rheometer at 10 ° C, 23 ° C and 75 ° C, respectively. The intersection of loss modulus (G “) and storage modulus (G ‘) provides the gelation time The results of the rheological measurements are summarized in Table 2.
Claims
- 1 . A polyamine selected from the group consisting of N, N’-diaminopropyl-2-methylcyclohexane-1,3-diamine and N, N’-diaminopropyl-4-methylcyclohexane-1,3-diamine.
- A process for the preparation of the polyamine according to claim 1 or a mixture of the polyamines according to claim 1, comprising
- Step 1, in which 2-methyl-cyclohexane-1, 3-diamine, 4-methyl-cyclohexane-1, 3-diamine or a mixture of 2-methyl-cyclohexane-1, 3-diamine and 4-methyl-cyclo – Hexane-1, 3-diamine is reacted with acrylonitrile to give the corresponding cyanoethylated intermediate, and
- Step 2, in which the cyanoethylated intermediate with hydrogen catalytically to N, N’-diaminopropyl-2-methyl-cyclohexane-1, 3-diamine, to N, N’-diaminopropyl-4-methyl-cyclohexane-1, 3 -diamine or to a mixture of N’-diaminopropyl-2-methyl-cyclohexane-1, 3-diamine and N, N’-diaminopropyl-4-methyl-cyclohexane-1, 3-diamine is hydrogenated.
- The method according to claim 2, characterized in that the cyanoethylated intermediate product obtained in step 1 is purified in step 2 in an intermediate step 1 a before further use.
- The method according to claim 2 or 3, characterized in that the product obtained in step 2 N, N’-diaminopropyl-2-methyl-cyclohexane-1, 3-diamine, N, N’-diaminopropyl-4-methyl-cyclohexane -1, 3-diamine or the mixture of N’-diaminopropyl-2-methylcyclohexane-1, 3-diamine and N, N’-diaminopropyl-4-methyl-cyclohexane-1, 3-diamine in one subsequent step 2a is cleaned.
- The method according to any one of claims 2 to 4, characterized in that for the hydrogenation in step 2, a Raney catalyst is used.
- A curable composition comprising one or more epoxy resins and one or more polyamines according to claim 1.
- The curable composition according to claim 6, characterized in that the one or more epoxy resins are selected from the group consisting of diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, diglycidyl ether of hydrogenated bisphenol A and diglycidyl ether of hydrogenated bisphenol F.
- The curable composition according to claim 6 or 7, characterized in that it contains one or more reactive diluents.
- The curable composition according to any one of claims 6 to 8, characterized in that it contains in addition to the polyamines according to claim 1 nor one or more further amine hardener.
- The curable composition according to any one of claims 6 to 9, characterized in that it still contains one or more further additives.
- 1 1. Process for the preparation of cured epoxy resins, characterized in that a curable composition according to any one of claims 6 to 10 is provided and then cured.
- The method according to claim 1 1, characterized in that the curing takes place in the presence of atmospheric moisture.
- A cured epoxy resin, characterized in that it is obtainable by the method according to claim 1 1.
- A cured epoxy resin, characterized in that it is obtainable by curing a curable composition according to one of claims 6 to 10.
- Use of one or more polyamines according to claim 1 as a hardener for epoxy resins for floor coatings.
Question
1. What Is CAS Number In Periodic Table?
All chemicals have a CAS registry numberr (Chemical Abstracts Service). Each and every chemical has a number that is usually unique. This is given in each case in square brackets. If you have access to CAS online, or some other search services, you can search for the element using the CAS registry number
2. What is the use of Methylcyclohexane?
It is used for coating including paint, ink, and adhesives and also as cleaning solvent. It is also used in some correction fluids (such as White-Out) as a solvent.
3. What is the CAS number of Methylcyclohexane?
Methylcyclohexane for synthesis. CAS 108-87-2, EC Number 203-624-3, chemical formula C₆H₁₁CH₃.
4. What is Diamine used for?
Diamine is one of the important raw materials to use for producing nylon plastics. The change of its production mode has an important impact on the production of nylon in the industry.
5. Is Methylcyclohexane an alkane?
It is a cycloalkane and a volatile organic compound. It derives from a hydride of a cyclohexane.