Carbonylation catalysts and methods of making the same
Disclosed herein are compounds and methods useful as carbonylation catalysts that improve steric properties so that reaction with epoxide is improved, reaction with lactones is avoided, and polymer bonds to the metal centers are weakened, which facilitates faster ring closure, that improve stability of the carbonylation catalyst by not being susceptible to hydrolysis, which reduces side products and improves recovery yields of the carbonylation catalyst after using to make lactones, and that have improved steric and electron properties so that release time of a lactone product is minimized, which reduces side reactions.
1 . A compound according to one of a following formulas:
wherein R is separately in each occurrence hydrogen, alkyl, or aryl group;
PL is selected from a group consisting of tetrahydrofuran, dioxane, diethyl ether, acetonitrile, carbon disulfide, pyridine, epoxide, ester, lactone, or a combination thereof; and
M is separately in each occurrence aluminum and chromium.
2 . The compound according to claim 1 wherein:
R is separately in each occurrence an alkyl or aryl group; and
PL is selected from a group consisting of, dioxane, diethyl ether, or a combination thereof.
3 . A method for preparing a compound according to claim 1 comprising:
contacting of a compound according to one of a formulas:
with a metalating agent to form one of the compounds according to a formula of:
and contacting the formed compounds with a metal carbonyl under condition such that one of the following compounds are formed:
wherein R is separately in each occurrence hydrogen, alkyl, or aryl group;
PL is selected from a group consisting of tetrahydrofuran, dioxane, diethyl ether, acetonitrile, carbon disulfide, pyridine, epoxide, ester, lactone, or a combination thereof; and
M is separately in each occurrence aluminum or chromium.
4 . The method according to claim 3 wherein:
R is separately in each occurrence an alkyl or aryl group; and
PL is selected from a group consisting of tetrahydrofuran, dioxane, diethyl ether, or a combination thereof.
5 . The method according to claim 3 comprising preparing one of the compounds according to one of the formulas:
by:
contacting a phenol which may be substituted at a 2 and/or 4 position with hydrogen, alkyl, or aryl group with a halogenating agent under conditions such that a halogen atom is added at a 6 carbon atom to form a halogenated phenol;
contacting the formed halogenated phenol with a trialkyl borate in presence of an alkyl lithium compound to replace the halogen atom with a boron dihydroxide group; and
contacting phenol containing a boron dihydroxide group with bipyridine or phenanthroline having halogen groups on carbons adjacent to nitrogen atoms in the presence of a palladium catalyst and an alkali metal carbonate under conditions to form one of the compounds of the formulas.
6 . The method of claim 5 , wherein contacting the formed halogenated phenol with the trialkyl borate in the presence of an alkyl lithium compound to replace the halogen atom with a boron dihydroxide group further comprises:
contacting the phenol containing a boron dihydroxide group with hydrochloric acid to quench a reaction.
7 . The method of claim 5 , wherein the trialkyl borate selected from a group consisting of trimethyl borate, triethyl borate, tripropyl borate, trisiopropyl borate, or any combination thereof.
8 . The method of claim 5 , wherein the alkali metal carbonate is sodium carbonate.
9 . The method of claim 5 , wherein contacting the formed compounds with the metal carbonyl under condition such that one of the compounds are formed includes:
contacting the formed compounds, the metal carbonyl, or both with a polar ligand so that that one of the compounds are formed.
10 . The method of claim 5 , wherein the alkyl lithium compound is selected from a group consisting of one or more of n-butyllithium, t-butyllithium, or any combination thereof.
11 . The method of claim 5 , wherein the halogenating agent is selected from a group consisting of one or more of bromine, N-bromosuccinimde, dibromoisocyanuric acid, or any combination thereof.
12 . The method of claim 5 , wherein the metal carbonyl is selected from a group consisting of NaCo(CO) 4 , Co 2 (CO) 8 , HCo(CO) 4 , or any combination thereof.
13 . The method of claim 5 , wherein the PL is selected from a group consisting of one or more of tetrahydrofuran, diethyl ether, or any combination thereof.
14 . The method of claim 5 , wherein the metalating agent is selected from a group consisting of one or more of (Et) 2 AlCl, (Et) 3 Al, CrCl 2 , or any combination thereof.
15 . The compound of claim 1 , wherein the PL is selected from a group consisting of the tetrahydrofuran.
16 . The method of claim 5 , wherein the PL is selected from a group consisting of of the tetrahydrofuran.