US 11,739,055 B2
Process for preparing diisocyanates based on lysine
Emmanouil Spyrou, Schermbeck (DE); Holger Loesch, Herne (DE); Susanne Kreischer, Herten (DE); Andrea Diesveld, Gescher (DE); Andrea Thesing, Ahaus (DE); and Jörg-Joachim Nitz, Essen (DE)
Assigned to Evonik Operations GmbH, Essen (DE)
Filed by Evonik Operations GmbH, Essen (DE)
Filed on Jun. 25, 2021, as Appl. No. 17/358,541.
Claims priority of application No. 20182431 (EP), filed on Jun. 26, 2020.
Prior Publication US 2021/0403417 A1, Dec. 30, 2021
Int. Cl. C07C 263/06 (2006.01); C07C 269/04 (2006.01)
CPC C07C 263/06 (2013.01) [C07C 269/04 (2013.01)] 20 Claims
 
1. Process for preparing a diisocyanate of the formula (A)

OG Complex Work Unit Chemistry
where R is selected from the group consisting of alkyl, aryl, and combinations thereof, comprising the following process steps in the indicated order:
1) Providing an intermediate of the formula (B) with a process using lysine and urea

OG Complex Work Unit Chemistry
where R and each R′ are independently selected from the group consisting of alkyl, aryl, and combinations thereof; and
2) thermolytic cleavage of the intermediate of the formula (B),
thereby affording the diisocyanate of the formula (A); and
wherein the process further includes one of the following series of process steps prior to process step 1):
either a.1) providing of lysine;
a.2) reacting the lysine with urea to form a urea adduct of the formula (C)

OG Complex Work Unit Chemistry
and
a.3) reacting the urea adduct of the formula (C) with an alcohol to form the intermediate of the formula (B);
or b.1) providing of lysine;
b.2) reacting the lysine with a base to form a lysine salt of the formula (Z);

OG Complex Work Unit Chemistry
where X is a counterion;
b.3) reacting the lysine salt of the formula (Z) with urea to form a urea salt of the formula (Y);

OG Complex Work Unit Chemistry
where X is a counterion;
b.4) reacting the urea salt of the formula (Y) with an alcohol to form a carbamate of the formula (X)

OG Complex Work Unit Chemistry
where each R′ is independently selected from the group consisting of alkyl, aryl, and combinations thereof, and X is a counterion;
b.5) reacting the carbamate of the formula (X) with an acid to form the carboxylic acid of the formula (W)

OG Complex Work Unit Chemistry
where each R′ is independently selected from the group consisting of alkyl, aryl, and combinations thereof; and
b.6) reacting the carboxylic acid of the formula (W) with an alcohol to form the intermediate of the formula (B);
or c.1) providing of lysine;
c.2) reacting the lysine with a base to form a lysine salt of the formula (Z);

OG Complex Work Unit Chemistry
where X is a counterion;
c.3) reacting the lysine salt of the formula (Z) with urea to form a urea salt of the formula (Y);

OG Complex Work Unit Chemistry
where X is a counterion;
c.4) reacting the urea salt of the formula (Y) with an alcohol to form the intermediate of the formula (B).