阅读说明：本技术 用于从蒸馏残余物中回收二异氰酸酯的方法 (Process for recovering diisocyanates from distillation residues ) 是由 J·莫拉夫斯基 T·洛登肯佩尔 S·朗格 R·贝林豪森 U·利森费尔德 M·默克尔 M· 于 2019-04-03 设计创作，主要内容包括：本发明涉及用于从蒸馏残余物中回收在室温下为固体的单体二异氰酸酯的方法,所述方法包括以下步骤：(i)提供至少一种包含在室温下为固体的二异氰酸酯的残余物,和(ii)在基于步骤(i)中提供的残余物的质量计小于2重量％的沥青的存在下,在至少一个捏合干燥器、叶片式干燥器和/或辊筒式干燥器中将所述残余物分离成包含在室温下为固体的单体二异氰酸酯的气态部分和贫化了在室温下为固体的二异氰酸酯的脆性残余物。(The present invention relates to a process for recovering monomeric diisocyanates that are solid at room temperature from distillation residues, said process comprising the steps of: (i) providing at least one residue comprising a diisocyanate that is solid at room temperature, and (ii) separating the residue in at least one kneading dryer, blade dryer and/or drum dryer in the presence of less than 2% by weight of bitumen, based on the mass of the residue provided in step (i), into a gaseous fraction comprising monomeric diisocyanate that is solid at room temperature and a brittle residue depleted of diisocyanate that is solid at room temperature.)

1. A process for recovering monomeric diisocyanates that are solid at room temperature from distillation residues, said process comprising the steps of:

(i) providing at least one residue comprising a diisocyanate that is solid at room temperature, and

(ii) (ii) separating the residue in the presence of less than 2% by weight of bitumen, based on the mass of the residue provided in step (i), in at least one kneading dryer, blade dryer and/or drum dryer into a gaseous fraction comprising monomeric diisocyanate solid at room temperature and a brittle residue depleted of diisocyanate solid at room temperature.

2. The process according to claim 1, characterized in that the kneading dryer, blade dryer and/or drum dryer are designed without cooling zones.

3. The process according to claim 1 or 2, characterized in that the separation of the residue in step (ii) is carried out in at least one kneading dryer and/or at least one roll dryer, particularly preferably in a roll dryer.

4. The process according to any of claims 1 to 3, characterized in that the separation in step (ii) is carried out in the presence of ≤ 1 wt.% of bitumen, preferably in the absence of bitumen.

5. The process according to any one of claims 1 to 4, characterized in that the temperature in step (ii) is from ≥ 130 ℃ to ≤ 270 ℃, preferably from ≥ 140 ℃ to ≤ 200 ℃, particularly preferably from ≥ 150 ℃ to ≤ 190 ℃.

6. The process according to any of claims 1 to 5, characterized in that the pressure in step (ii) is from ≥ 1mbar to ≤ 1020mbar, preferably from ≥ 1mbar to ≤ 25mbar, particularly preferably from ≥ 1mbar to ≤ 10 mbar.

7. Process according to any one of claims 1 to 6, characterized in that the diisocyanate which is solid at room temperature is 1, 5-naphthalene diisocyanate, 1, 8-naphthalene diisocyanate or 1, 4-benzene diisocyanate, preferably 1, 5-naphthalene diisocyanate or 1, 4-benzene diisocyanate, particularly preferably 1, 5-naphthalene diisocyanate.

8. The process according to any one of claims 1 to 7, characterized in that the residue has an average residence time in the at least one kneading dryer, paddle dryer and/or drum dryer of ≥ 0.5 min to ≤ 4 hr min, preferably ≥ 0.5 min to ≤ 60 min, particularly preferably ≥ 0.5 min to ≤ 15 min, very particularly preferably ≥ 1 min to ≤ 10 min at the time of separation in step (ii).

9. The process according to any one of claims 1 to 8, characterized in that the brittle residue obtained in step (ii) is discharged semi-continuously.

10. The process according to any one of claims 1 to 9, characterized in that the brittle residue obtained in step (ii) comprises 5% by weight or less, preferably 2% by weight or less, particularly preferably 0.2% by weight or less, very particularly preferably < 0.1% by weight, based on the total mass of the residue, of monomeric diisocyanates which are solid at room temperature.

11. Process according to any one of claims 1 to 10, characterized in that the residue provided in step (i) comprising the diisocyanate solid at room temperature is derived from the distillation of the diisocyanate prepared by phosgenation of the corresponding diamine.

12. Monomeric diisocyanates which are solid at room temperature, obtained or obtainable by the process according to any one of claims 1 to 11.

13. Use of a kneading dryer, a blade dryer and/or a drum dryer for minimizing the use of auxiliaries when embrittling residues containing diisocyanates which are solid at room temperature.

14. Composition comprising at least one monomeric diisocyanate according to claim 12 which is solid at room temperature and at least one NCO-reactive compound, preferably at least one polyester polyol.

15. An elastomer obtained or obtainable by curing the composition according to claim 14, optionally under heating.

Example 1

The residue from the distillation of 1, 5-naphthalene diisocyanate prepared by phosgenation of 1, 5-naphthalene diamine was applied to a Kofler heating stage. The residue still contained about 75% by weight of monomeric 1, 5-naphthalene diisocyanate (determined as area percentage by GPC according to DIN 55672-1: 2007-08). The Kofler heating stage was operated at a temperature of 100 to 250 ℃. At 250 ℃, it embrittles rapidly within 2 minutes and the residue can be scraped off as a fine powder. The embrittlement then continues in the region of lower temperature, and after about 3 hours, the region also at 160 ℃ is embrittled and can be scraped off in the form of flakes. Below 130 c, the embrittlement is no longer present.