101-68-8 Usage
Uses
Used in Polyurethane Products:
4,4'-Diphenylmethane diisocyanate is used as a key component in the production of polyurethane products, such as elastic and rigid foams, due to its ability to form strong and versatile polymers.
Used in Coatings and Adhesives:
MDI is used as a binder in the production of polyurethane coatings, which are utilized in various applications, including building materials, vehicles, and ship parts. It is also used in the formulation of adhesives for its strong bonding capabilities.
Used in Elastomers and Synthetic Rubbers:
4,4'-Diphenylmethane diisocyanate is used as a crucial ingredient in the manufacturing of elastomers and synthetic rubbers, contributing to their elasticity and durability.
Used in Fibers and Textiles:
MDI is used in the preparation of polyurethane resin and Spandex fibers, which are essential in the textile industry for their stretchable and resilient properties.
Used in Lacquers and Plastics:
4,4'-Diphenylmethane diisocyanate is used in the production of polyurethane lacquers, foam plastics, rubber, and glues, providing them with enhanced strength and flexibility.
Used in Rubber Bonding:
MDI is employed in the bonding of rubber to rayon, enhancing the adhesion and durability of the final product.
Preparation
Phosgene (800 g, 8 mol) (for a safe source) was dissolved in o-dichlorobenzene (2000 mL), and the resulting solution was cooled in an ice-salt bath. To the stirred solution, a hot solution of 4,4'-diaminodiphenylmethane (200 g, 1.01 mol) in o-dichlorobenzene (1000 mL) was slowly added through a heated dropping funnel. The rate of addition was regulated so that the temperature of the phosgene solution did not rise substantially above 0°C. The fine suspension that resulted was slowly heated and additional phosgene (700 g, 7.1 mol) was added at 130 °C until a clear solution appeared. After purging with carbon dioxide, the solvent was removed in vacuo and the product was purified by vacuum distillation. At 156–158 °C (0.1 mmHg), 215 g (0.85 mol, 84%) of 4,4’-diphenylmethane diisocyanate was obtained. Several procedures for the preparation of isocyanates with phosgene have been described. Nevertheless, many of them require the delivery of gaseous phosgene from an external source, such as a pressurized cylinder.
Air & Water Reactions
4,4'-Diphenylmethane diisocyanate is not soluble in water.
Reactivity Profile
Isocyanates and thioisocyanates, such as 4,4'-Diphenylmethane diisocyanate, are incompatible with many classes of compounds, reacting exothermically to release toxic gases. Reactions with amines, aldehydes, alcohols, alkali metals, ketones, mercaptans, strong oxidizers, hydrides, phenols, and peroxides can cause vigorous releases of heat. Acids and bases initiate polymerization reactions in these materials. Some isocyanates react with water to form amines and liberate carbon dioxide. Base-catalysed reactions of isocyanates with alcohols should be carried out in inert solvents. Such reactions in the absence of solvents often occur with explosive violence, [Wischmeyer(1969)].
Health Hazard
Breathlessness, chest discomfort, and reduced pulmonary function.
Health Hazard
MDI can present a moderate to severe healthhazard, because of respiration of its vapors and particulates. It can contaminate the environment during foam application; concentrations in air were measured as high as5 mg/m3, mostly as particulates (ACGIH1986).The toxic route is primarily inhalation.The vapor pressure of this compound atambient temperature is very low, 0.00014torr at 25°C. However, when heated to about75°C, the acute health hazard is greatlyenhanced (Hadengue and Philbert 1983). Theacute toxic symptoms were found to besimilar to those of toluene-2,4-diisocyanateand other aromatic isocyanates. Inhalation ofits vapors or particulates can cause bronchitis, coughing, fever, and an asthma-likesyndrome. Other symptoms were nausea,shortness of breath, chest pain, insomnia,and irritation of the eyes, nose, and throat.The immunologic response, however, variedamong humans. Exposure to 0.1–0.2 ppmfor 30 minutes is likely to manifest the acutetoxic effects in humans.MDI is an eye and skin irritant. Contactwith skin can produce eczema. The acuteoral toxicity of this compound is very low,considerably lower than that of toluene-2,4-diisocyanate. The lethal dose for rats was31.7 g/kg. MDI showed positive in mutagenic testingon Salmonella typhimurium. There is noreport that indicates its carcinogenicity.
Fire Hazard
Noncombustible; flash point (open cup)
202°C (395°F). MDI reactions with strong
oxidizers, acids, and bases can be vigorous.
Flammability and Explosibility
Nonflammable
Contact allergens
MDI is used in the manufacture of various polyurethane products: elastic and rigid foams, paints, lacquers, adhesives, binding agents, synthetic rubbers, and elastomeric fibers.
Safety Profile
Poison by inhalation.
Mildly toxic by ingestion. Human systemic
effects by inhalation: increased immune
response and body temperature. A skin and
eye irritant. An allergic sensitizer.
Questionable carcinogen. Mutation data
reported. A flammable liquid. When heated
to decomposition it emits toxic fumes of
NOx and SOx.
Potential Exposure
MDI is used in the production of polyurethane foams and plastics; polyurethane coatings; elastomers, and thermoplastic resins.
Environmental Fate
Due to its low vapor pressure (0.000 62 Pa at 20 ℃), MDI
partitioning to the atmosphere is limited; and vapors are
rapidly eliminated by reaction with hydroxyl radicals (22 h
half-life). Degradation by either direct photolysis or hydrolysis
by water vapor to methylenedianiline (MDA) does not play
a significant role in the atmospheric fate of MDI. In water, the
isocyanate group of MDI can be rapidly hydrolyzed to an
amine (<1 min half-life) that in turn reacts at a much faster rate
with another isocyanate group to yield urea. Because MDI has
two isocyanate groups, these reactions lead to cross-linked
polyureas, which are inert, insoluble solids. Unless MDI is
well dispersed in water, these processes result in the formation
of a solid polyurea crust that encases the unreacted material,
restricts both water ingress and amine egress, and leads to
higher yields of polyurea. Under stirred aqueous conditions,
the fraction of 4,4'-MDI converted to 4,4'-MDA is less than 1%;
unstirred, the fraction is 0.005%. MDI released to soil will not
exhibit significant transport to other environmental media due
to the favored reaction with water to form inert polyureas and
binding to the soil biomass. As expected, pMDI and the waterinsoluble
oligo- and polyureas that form when pMDI enters an aqueous environment showed no biodegradation over 28 days
in a guideline study.
Shipping
UN2811 Toxic solids, organic, n.o.s., Hazard
Class: 6.1; Labels: 6.1-Poisonous materials, Technical
Name Required
Toxicity evaluation
The primary health concern with exposure to MDI is dermal
and respiratory sensitization. Both are initiated by conjugation
of MDI isocyanate groups with macromolecules at the point of
contact, which forms a hapten that subsequently activates
immunologic processes resulting in sensitization. Data in
animals indicate dermal contact with MDI can lead to respiratory
sensitization. However, the human relevance of these
observations is unclear since there are no validated animal
models that accurately reflect the respiratory sensitization
process and responses seen in humans. The low incidence of
pulmonary tumors observed in chronic inhalation studies at
maximum tolerated concentrations of pMDI is most likely the
result of nongenotoxic cell proliferation associated with
chronic inflammation and/or hyperplasia rather than a direct
effect on DNA.
Incompatibilities
May form explosive mixture with air.
Isocyanates are highly flammable and reactive with many
compounds, even with themselves. Incompatible with
oxidizers (chlorates, nitrates, peroxides, permanganates,
perchlorates, chlorine, bromine, fluorine, etc.); contact
may cause fires or explosions. Reaction with moist air,
water or alcohols may form amines and insoluble polyureas and react exothermically, releasing toxic, corrosive or
flammable gases, including carbon dioxide; and, at the
same time, may generate a violent release of heat increasing the concentration of fumes in the air. Incompatible
with amines, aldehydes, alkali metals, ammonia, carboxylic acids, caprolactum, alkaline materials, glycols,
ketones, mercaptans, hydrides, organotin catalysts, phenols, strong acids, strong bases, strong reducing agents
such as hydrides, urethanes, ureas. Elevated temperatures
or contact with acids, bases, tertiary amines, and acylchlorides may cause explosive polymerization. Attacks
some plastics, rubber and coatings. May accumulate static
electrical charges, and may cause ignition of its vapors.
Unstable above 100F/38C. Polymerizes at temperatures
above 204C. Contact with metals may evolve flammable
hydrogen gas.
Waste Disposal
Controlled incineration
(oxides of nitrogen are removed from the effluent gas by
scrubbers and/or thermal devices).
Check Digit Verification of cas no
The CAS Registry Mumber 101-68-8 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 1,0 and 1 respectively; the second part has 2 digits, 6 and 8 respectively.
Calculate Digit Verification of CAS Registry Number 101-68:
(5*1)+(4*0)+(3*1)+(2*6)+(1*8)=28
28 % 10 = 8
So 101-68-8 is a valid CAS Registry Number.
InChI:InChI=1/C15H10N2O2/c18-10-16-14-5-1-12(2-6-14)9-13-3-7-15(8-4-13)17-11-19/h1-8H,9H2
101-68-8Relevant articles and documents
Solvent-free thermal decomposition of methylenediphenyl di(phenylcarbamate) catalyzed by nano-Cu2O
Wang, Qingyin,Kang, Wukui,Zhang, Yi,Yang, Xiangui,Yao, Jie,Chen, Tong,Wang, Gongying
, p. 548 - 558 (2013)
Methylene di(phenylisocyanate) (MDI) was prepared by thermal decomposition of methylenediphenyl di(phenylcarbamate) (MDPC) under solvent-free conditions with a nano-Cu2O catalyst. The preparation of nano-Cu2O was investigated in deta
Ionic liquid-mediated solvothermal synthesis of 4,4′-methylenediphenyl diisocyanate (MDI): An efficient and environment-friendly process
Duan,You,Liu,Ma,Zhou,Zhang,Zhang
, p. 12243 - 12255 (2018)
4,4′-Methylenediphenyl diisocyanate (4,4′-MDI) is an immensely important intermediate employed in the manufacturing of polyurethanes. Many synthetic routes have been developed over the decades for the synthesis of 4,4′-MDI compounds on a large scale; these compounds are highly toxic and hazardous in nature. In this study, an environment-friendly route is proposed for the synthesis of 4,4′-MDI using 4,4′-diaminodiphenylmethane and dimethyl carbonate (DMC) as starting materials, which are nontoxic in nature. The synthesis of ionic liquids (ILs) and their utilization in the decomposition reaction are systematically investigated. Imidazole-functionalized ionic liquids were prepared for the synthesis of 4,4′-MDI, and their thermal performances were evaluated by TGA. We found that in comparison with other imidazole-functionalized ionic liquids, 1-ethoxycarbonylmethyl-3-methylimidazolium tetrafluoroborate ([EAmim]BF4) exhibited preferable thermal activity for the decomposition of 4,4′-methylenediphenyl dimethylcarbamate (4,4′-MDC). Moreover, these ILs were more effective when they were combined with zinc as a catalyst, which enhanced the decomposition of MDC. Under optimal conditions, the yield of MDI compared to that of Zn(OAc)2-[EAmim]BF4 catalyst increased up to 96%. The mechanism of the enhanced performance of ionic liquids by catalytic activity of zinc acetate was also investigated.
A new and efficient catalytic method for synthesizing isocyanates from carbamates
Uriz, Pedro,Serra, Marc,Salagre, Pilar,Castillon, Sergio,Claver, Carmen,Fernandez, Elena
, p. 1673 - 1676 (2002)
Operationally simple, recyclable and environmentally friendly montmorillonite efficiently catalyses dealcoholysis of a wide range of mono- and dicarbamates to isocyanates.
FLOW CHEMISTRY SYNTHESIS OF ISOCYANATES
-
Paragraph 0175; 0185-0187; 0325; 0330-0335, (2021/06/22)
The disclosure provides, inter alia, safe and environmentally-friendly methods, such as flow chemistry, to synthesize isocyanates, such as methylene diphenyl diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and tetramethylxylene diisocyanate.
METHOD FOR PRODUCING CARBAMATE AND METHOD FOR PRODUCING ISOCYANATE
-
Paragraph 0367; 0369-0379; 0399; 0402-0403, (2021/06/22)
The present invention provides a method for producing a carbamate that includes a step (1) and a step (2) described below: (1) a step of producing a compound (A) having a urea linkage, using an organic primary amine having at least one primary amino group per molecule and at least one compound selected from among carbon dioxide and carbonic acid derivatives, at a temperature lower than the thermal dissociation temperature of the urea linkage; and(2) a step of reacting the compound (A) with a carbonate ester to produce a carbamate.
ISOCYANATE PRODUCTION METHOD
-
Paragraph 0419-0430; 0447-0451; 0454-0458; 0462, (2020/05/02)
An isocyanate production method according to the present invention is a method in which an isocyanate is produced by subjecting a carbamate to thermal decomposition, and includes: a step of preparing a mixture liquid containing the carbamate, an inactive solvent and a polyisocyanate compound; a step of conducting a thermal decomposition reaction of the carbamate by continuously introducing the mixture liquid into a thermal decomposition reactor; a step of collecting a low-boiling decomposition product by continuously extracting the low-boiling decomposition product in a gaseous state from the reactor, the low-boiling decomposition product having a boiling point lower than the polyisocyanate compound; and a step of collecting a high-boiling component by continuously extracting, from the reactor, a liquid phase component which is not collected in a gaseous state at the step of collecting the low-boiling decomposition product.
Method for preparing diphenylmethane diisocyanate through efficient catalysis by polyoxometallate
-
Paragraph 0023-0024; 0025-0026; 0027-0028; 0029-0044, (2020/11/09)
The invention discloses a method for preparing 4,4'-diphenylmethane diisocyanate from 4,4'-diaminodiphenylmethane and methanol under the catalysis of a polyoxometallate (wherein the polyoxometallate is one of six basic configurations of a Keggin type, a Wells-Dawson type, a Lindeqvist type, a Waugh type Anderson type and a Silverton type, and the Anderson type configuration is mainly adopted). Themethod comprises the following specific steps: adding M-Anderson type heteropolyacid (M is Mn, Fe, Al, Cr, Co, Ni, Cu, Zn and the like) as a catalyst, 4,4'-diaminodiphenylmethane, methanol, hydrogenperoxide, an acid-binding agent, a dehydrating agent and an anhydrous acetonitrile solvent into a clean reaction tube; and finally sleeving an oxygen ball above a reactor, and carrying out a completestirring reacting for a period of time by air magnetic force at a certain temperature to obtain a target compound. According to the method disclosed by the invention, M-Anderson type heteropolyacid isused as the catalyst, and the catalyst has extremely high reaction activity, takes common non-noble metals as the center, further has popularization and utilization values and can be recycled after simple treatment, so that the cleanness of industrial reaction is improved, and the environmental protection pressure is reduced.
Mechanistic Study of Stress Relaxation in Urethane-Containing Polymer Networks
Brutman, Jacob P.,Fortman, David J.,De Hoe, Guilhem X.,Dichtel, William R.,Hillmyer, Marc A.
, p. 1432 - 1441 (2019/02/24)
Cross-linked polymers are used in many commercial products and are traditionally incapable of recycling via melt reprocessing. Recently, tough and reprocessable cross-linked polymers have been realized by incorporating cross-links that undergo associative exchange reactions, such as transesterification, at elevated temperatures. Here we investigate how cross-linked polymers containing urethane linkages relax stress under similar conditions, which enables their reprocessing. Materials based on hydroxyl-terminated star-shaped poly(ethylene oxide) and poly((±)-lactide) were cross-linked with methylene diphenyldiisocyanate in the presence of stannous octoate catalyst. Polymers with lower plateau moduli exhibit faster rates of relaxation. Reactions of model urethanes suggest that exchange occurs through the tin-mediated exchange of the urethanes that does not require free hydroxyl groups. Furthermore, samples were incapable of elevated-temperature dissolution in a low-polarity solvent (1,2,4-trichlorobenzene) but readily dissolved in a high-polarity aprotic solvent (DMSO, 24 to 48 h). These findings indicate that urethane linkages, which are straightforward to incorporate, impart dynamic character to polymer networks of diverse chemical composition, likely through a urethane reversion mechanism.
Preparation method 4, 4' diphenyl methane diisocyanate (by machine translation)
-
Paragraph 0027-0058, (2019/10/01)
The invention relates to 4. In 4 'diphenyl methane diisocyanate preparation method, catalyst polyoxometallate, solvent are added to the reaction vessel, raw materials 4, 4' - diaminodiphenylmethane and benzene silane, acid binding agent and dehydrating agent, are uniformly mixed, and gaseous carbon dioxide, which is stirred sufficiently at certain temperature, is added to obtain the product. M-Anderderson type heteropoly acid is adopted as a catalyst, and the catalyst needs mild reaction conditions, and is high in specificity and high, and is high in specificity. The recyclable environment-friendly, recyclable and environmentally friendly, improves the cleanliness, improves the process economy, reduces the manufacturing cost and the generation, reduces the environment-friendly pressure, and is beneficial to industrial production. (by machine translation)
Preparation method for diphenylmethane diisocyanate
-
Paragraph 0036-0079; 0086-0087, (2019/11/19)
The invention provides a preparation method for diphenylmethane diisocyanate. The preparation method comprises a step of subjecting diphenylmethane dicarbamate to a pyrolysis reaction in an inert solvent having a boiling point lower than the boiling point of diphenylmethane diisocyanate in the presence of a catalyst so as to produce diphenylmethane diisocyanate. The preparation method provided bythe invention has the advantages of high reaction conversion rate, high yield, simple equipment and process and mild reaction conditions, and can meet the demands of industrial production.
