ChemicalBook CAS DataBase List 1,5-Naphthalene diisocyanate

1,5-Naphthalene diisocyanate synthesis

5synthesis methods

Product Name:1,5-Naphthalene diisocyanate
CAS Number:3173-72-6
Molecular formula:C12H6N2O2
Molecular Weight:210.19

Naphthylene 1,5-diisocyanate (NDI) is prepared from naphthalene as follows:

Carbamic acid, 1,5-naphthalenediylbis-, dibutyl ester (9CI)

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Yield:3173-72-6 91%

Reaction Conditions:

1,2-dimethyl-3-ethylimidazole perchloric acid at 190 - 240; under 37.5038 Torr; for 2.16667 h;

Steps:

10

In to a thermal cracking device, 500 mL of 1,2-dimethyl-4-ethylimidazole perchloric acid ionic liquid ([EMMIm]ClO₄) and 0.5 g of supported metal oxide solid catalyst E were added. At 190° C., under an absolute pressure of 5000 Pa and a stirring rotation speed of 600 rounds/min, 235 g of naphthalene-1,5-dibutylurethane was further added. After reacting for 0.5 h, 1,5-naphthalene diisocyanate (NDI) and butanol were collected in the pre-(about 0° C.), post-(about -20° C.) collecting devices, respectively. The reaction was continued for 1.5 hours at 190° C. under a degree of vacuum of 5000 Pa. Then, the temperature was turned to 240° C. under the same degree of vacuum for 10 min. All of the products, raw materials and intermediates in the thermal cracking device were collected into the pre-collecting device to obtain a mixture containing 1,5-naphthalene-isocyanate-butylurethane (monoisocyanate), naphthalene-1,5-dibutylurethane and NDI. The mixing liquid was subjected to chromatography analysis. The measured NDI had a purity of 93% and a NDI chromatography yield of 95%. Then the mixing liquid was subjected to rectification. The isolated NDI yield was 91%. The residual product after rectification was subjected to the next thermal cracking for circulation in turn. The ionic liquid could be reused for several times.

References:

US2011/21810,2011,A1 Location in patent:Page/Page column 5