3173-72-6 Usage
Description
Naphthalene diisocyanate (NDI) occurs as white to lightyellow
crystalline flakes with a characteristic odor. NDI is
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.
NDI can react with water to form amines and liberate
carbon dioxide.
Chemical Properties
Naphthylene 1,5-diisocyanate is a solid, m.p. 128°C. It has a lower vapour
pressure than tolylene diisocyanate and is therefore less toxic in use; it does,
however, have sensitizing properties.
Uses
Different sources of media describe the Uses of 3173-72-6 differently. You can refer to the following data:
1. Manufacture of polyurethane solid elastomers.
2. Naphthylene 1,5-diisocyanate is mainly
used for the production of elastomers.
3. NDI is used as a curing agent in the manufacture of elastomers.
Preparation
Naphthylene 1,5-diisocyanate (NDI) is prepared from naphthalene as follows:
General Description
White to light-yellow crystalline flakes.
Reactivity Profile
Isocyanates and thioisocyanates, such as 1,5-Naphthalene 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)].
Flammability and Explosibility
Nonflammable
Safety Profile
A powerful allergen. An
irritant. Questionable carcinogen. When
heated to decomposition it emits toxic
fumes of NOx.
Environmental Fate
NDI is a synthetic organic chemical. It is a natural derivative of
primary amines with the general formula R–N]C]O which
does not occur naturally in the environment. At room temperature
it can be a liquid or crystal. It is miscible with alcohol,
diglycol, monoethyl ether, ether, acetone, carbon tetrachloride,
benzene, chlorobenzene, kerosene, and olive oil; however, it
may react violently with alcohol, water, acid, bases, and strong
alkaline materials and tertiary amines and generate enough heat
to self-ignite and release toxic combustion products. NDI is not
readily biodegradable; however, it reacts with water and most
acids producing unstable carbonic acids, which subsequently
decarboxylate yielding relatively chemically inert and insoluble
polymeric urea. While these polyureas are persistent, studies
have indicated that they pose virtually no potential for adverse
impacts on the aquatic environment. Due to hydrolysis in water,
bioaccumulation of NDI is not expected. Since the hydrolysis
products formed are irritants, there is a potential for inhalation
exposure. The degree stability is a function of humidity.
Toxicity evaluation
The toxicological properties of isocyanates are attributed to
the –N=C=O group. It is thought to react vigorously and
exothermically with water forming an unstable carbamic
acid that dissociates to form a primary amine with liberation
of CO2. Hence, the primary amine will react further
generating a urea derivative. Isocyanates also react readily
with all organic compounds resulting in polymerization.
Such reactions denature proteins, form abnormal crosslinkages,
and generally disorganize the protein resulting in
alteration of its normal function. This reactivity with
proteins can account for its potency as a sensitizing agent.
An IgE- or IgG-mediated mechanism has been proposed,
but has not been definitively linked to isocyanate exposure.
There is also evidence that inflammation and morphological
changes of the bronchia mucosa and direct neurogenic
mechanisms could be involved in the mechanics of toxicity.
Thus, more than one reaction may occur in a system at
a given time.
Check Digit Verification of cas no
The CAS Registry Mumber 3173-72-6 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 3,1,7 and 3 respectively; the second part has 2 digits, 7 and 2 respectively.
Calculate Digit Verification of CAS Registry Number 3173-72:
(6*3)+(5*1)+(4*7)+(3*3)+(2*7)+(1*2)=76
76 % 10 = 6
So 3173-72-6 is a valid CAS Registry Number.
InChI:InChI=1/C12H6N2O2/c15-7-13-11-5-1-3-9-10(11)4-2-6-12(9)14-8-16/h1-6H
3173-72-6Relevant articles and documents
Method for synthesizing 1,5-naphthalene diisocyanate
-
Paragraph 0034; 0037-0038; 0041-0042, (2019/10/04)
The invention discloses a method for synthesizing 1,5-naphthalene diisocyanate. The method comprises the following steps: 1) synthesizing 1,5-naphthalene dicarbamate from 1,5-naphthalene diamine and an auxiliary material A; 2) pyrolyzing the 1,5-naphthale
Process for the preparation of 5-nitro-3,4-dihydro-1(2H)-naphthalenone, 1,5-naphthalendiamine and 1,5-naphthalendiisocyanate
-
Page 8, (2008/06/13)
A process for the production of 1,5-naphthalene diamine (I) comprises reaction of 4-(2-nitrophenyl)-n-butyronitrile to 4-(2-nitrophenyl)-n-butyric acid. Independent claims are included for: (1) a process for the production of 5-nitro-3,4-dihydro-1(2H)-naphthalinone by reaction of 4-(2-nitrophenyl)-n-butyronitrile to 4-(2-nitrophenyl)-n-butyric acid and; (2) a process for the production of 1,5-naphthalene diisocyanate by phosgenation of 1,5-naphthalene diamine (I).
Linking metal centres with diimido ligands: Synthesis, electronic and molecular structure and electrochemistry of organometallic ditungsten complexes [{WCl2(Ph2PMe)2(CO)}2(N-X-N)] (X = π-conjugated organic)
Hogarth, Graeme,Humphrey, David G.,Kaltsoyannis, Nikolas,Kim, Woo-Sung,Lee, Mo-Yin,Norman, Tim,Redmond, Simon P.
, p. 2705 - 2723 (2007/10/03)
Tungsten(IV) diimido-bridged complexes [{WCl2(Ph2PMe)2(CO)}(μ-N-X-N)] have been prepared via oxidative addition of diisocyanates to two equivalents of [WCl2(Ph2PMe)4]. para-Substituted monoimido complexes [WCl2(Ph2PMe)2(CO)(NC6H 4X-p)] (X = I, Br or C≡CPh) have also been prepared but attempts to couple the X = I complex as a route to diimido-bridged complexes were unsuccessful. All complexes are air-stable crystalline solids and five diimido (N-X-N = p-NC6H4N, p-N-o-MeC6H3N, p-N(o-MeOC6H3C6H3OMe-o)N, 1,5-NC10H6N or m-NC6H4N) and one monoimido complex (X = I) have been characterised crystallographically. All show the same gross structural features, namely a trans arrangement of phosphines and cis chlorides. The central aryl ring generally lies approximately in the Cl2(CO) plane (torsional angles 4.1-26.1°) except for one complex in which the ring lies almost perpendicular to this (torsional angle 80.2°). A series of density functional calculations conducted on model mono- and di-imido tungsten-(VI) and -(V) compounds indicated that the most stable aryl ring orientation is perpendicular to the plane containing the trans phosphines, i.e. as found in all cases except one (N-X-N = p-NC6H4N). The anomaly in the latter may be due to cocrystallisation with chlorobenzene. In order to assess the degree of communication between the tungsten(IV) centres through the highly π-conjugated diimido linkages, electrochemical studies have been carried out. All diimido-bridged complexes show two closely spaced oxidative processes at low temperature indicative of weak electronic communication. The reductive chemistry of the para-phenylene bridged complexes is different from other diimido complexes, displaying two closely spaced reductive processes. Spectro-electrochemical studies have also been carried out on N-X-N = p-NC6H4N, oxidation at +1.2 V leading to CO loss. In order to gain further insight into the nature of the electronic communication between metal centres density functional calculations were carried out and were generally in agreement with the electrochemical results, suggesting that there is at best a weak interaction between the metal centres in these π-conjugated diimido-bridged complexes.