Method for functionalization of nucleophiles

Process for the preparation of acetoacetates and other .beta.-ketoesters is provided, involving reaction of nitrogen, oxygen or sulfur nucleophiles with a tetriaryalkyl acetoacetate or tetriaryalkyl .beta.-ketoester.

DESCRIPTION 
This invention relates to the functionalization of nucleophiles with 
.beta.-dicarbonyl compounds. In one aspect, this invention relates to the 
acetoacetylation of nucleophiles. In another aspect, this invention 
relates to the acetoacetylation of low molecular weight nucleophiles. In 
yet another aspect, this invention relates to the acetoacetylation of 
polymeric nucleophiles. 
BACKGROUND 
The acetoacetate moiety has been used in the coatings industry to impart 
functionality capable of undergoing a variety of cross-linking reaction 
while simultaneously lowering the viscosity of the resulting formulation. 
Among the reactions which can be used to promote cross-linking of 
acetoacetylated polymeric materials are reactions with activated olefins 
(commonly referred to as the Michael reaction), diamines, melamine, 
isocyanates, and the like. Coatings prepared from acetoacetylated polymers 
using such cross-linking strategies often exhibit improved 
stain-resistance, salt-spray resistance and better adhesion to the metal 
surface when compared to coatings prepared from nonacetoacetylated 
polymers. 
Interest in the use of acetoacetylated materials in coatings has led to the 
need for general synthetic procedures for the preparation of 
acetoacetylated compounds which can be readily practiced on industrial 
scale. It is known that acetoacetylated acrylic resins can be prepared by 
the copolymerization of acetoacetoxyethyl methacrylate with acrylic or 
methacrylic monomers. Alternatively, acetoacetylated polymers or resins 
can be prepared by the acetoacetylation of the polymeric substrate, rather 
than by polymerization of acetoacetylated monomers. One substrate for 
which this method of synthesis is generally required is in the preparation 
of acetoacetylated polyester resins. 
Simple acetoacetylated materials can be prepared in a variety of ways. For 
example, an appropriate nucleophile can be treated with diketene. 
Alternatively, such nucleophile can be subjected to a thermal reaction 
with 2,2,6-trimethyl-4H-1,3-dioxin -4-one (TKD, the diketene-acetone 
adduct). As yet another alternative, such nucleophile can be subjected to 
transesterification with another acetoacetate moiety (referred to 
hereinafter as "transacetoacetylation"). 
The industrial-scale use of diketene for such applications is impractical 
due to strict governmental regulations regarding the shipping of this 
material. In addition, the classification of diketene as a lachrymator 
make the large scale use of this material undesirable. The dioxinone, TKD, 
while effective for acetoacetylation, is currently too costly a raw 
material to be employed for large scale industrial applications. 
While transesterification reactions are well known in the preparation of 
polyester coating resins, transesterification of acetoacetates (i.e., 
transacetoacetylation) has not found wide spread application. One 
published procedure for the preparation of acetoacetic acid derivatives 
involves heating solutions of a higher boiling alcohol with an excess of 
methyl or ethyl acetoacetate while the volatile methyl or ethyl alcohol 
co-product is removed by distillation. Reaction times for such procedure 
are on the order of many hours when carried out at elevated temperatures 
(about 100.degree. C.). Another method for transacetoacetylation which has 
been suggested in the art involves contacting the alcohol of interest with 
a large excess of methylacetoacetate and a 4-dimethylaminopyridine 
catalyst in a high boiling hydrocarbon solvent such as toluene for an 
extended period of time. An alternate method for transacetoacetylation 
disclosed in the art is the use of titanium catalysts. 
Seebach et al, Synthesis, 1982, pages 138-141, disclose the use of 
substantial amounts of titanium (IV) alkoxides (tetraalkyl titanates) as 
catalysts in the transacetacetylation of alcohols. More specifically, this 
reference discloses the reaction of tertiary (t) butyl acetoacetate with 
n-butanol and benzyl alcohol in the presence of tetraethyl titanate 
wherein the molar ratio of the titanate used to t-butyl acetoacetate was 
0.21 or 0.35. 
Yet another prior art disclosure of transesterification reactions employing 
acetoacetic moieties is found in European Patent Application 227,454, 
assigned to Cook Paint and Varnish Inc. The reaction between a polyhydroxy 
functional monomer or polymer and an alkyl monofunctional acetoacetate is 
disclosed. Suitable acetoacetate esters are disclosed to be methyl 
acetoacetate, ethyl acetoacetate, isopropyl acetoacetate, butyl 
acetoacetate, t-butyl acetoacetate, methyl benzyl acetoacetate and dodecyl 
acetoacetate. The examples in this disclosure demonstrate only the use of 
ethyl acetoacetate. There is no suggestion in the reference of any benefit 
from using one acetoacetate moiety rather than another taken from the 
above list of "suitable" compounds. 
The high dilution, large amounts of catalyst used and long reaction times 
involved make each of the prior art procedures for transacetoacetylation 
impractical, especially when application on a commercial scale is 
contemplated. Prior art procedures are particularly ill-suited for the 
acetoacetylation of higher molecular weight (including polymeric) 
nucleophiles. There is, therefore, a need in the art for simplified 
procedure for transacetoacetylation, which procedure does not require 
extreme reaction conditions or large quantities of unreactive materials. 
STATEMENT OF THE INVENTION 
In accordance with the present invention, we have discovered that a variety 
of nucleophiles can be functionalized by contacting such nucleophiles with 
a specifically defined .beta.-dicarbonyl compound, i.e., a 
.beta.-ketoester as defined below under moderate reaction conditions of 
time and temperature. 
The invention functionalization process is relatively rapid, can be carried 
out in the substantial absence of catalysts and/or solvent, avoids the use 
of toxic and/or more expensive starting materials, is of very general 
applicability, provides products with low level of residual color, and 
produces volatile and readily recoverable coproducts.

DETAILED DESCRIPTION OF THE INVENTION 
In accordance with the present invention, there is provided a method for 
the functionalization of nucleophiles having the structural formula: 
EQU HY--R.sub.X 
wherein Y is selected from nitrogen, oxygen or sulfur; 
wherein R is selected from the group consisting of: 
C.sub.1 up to C.sub.12 hydrocarbyl radical substituted with 0 up to 3 
hydroxyl units, formyl units, nitro units, chlorine atoms, bromine atoms, 
ester moieties of the structure: 
##STR1## 
wherein Z is a hydrocarbyl moiety having in the range of 1 up to 6 carbon 
atoms, or alkoxy moieties of the structure, -OZ, wherein Z is as defined 
above; and wherein R can also be H when Y is N; and 
wherein x is 1 when Y is 0 or S, and x is 2 when Y is N; 
said process comprising contacting said nucleophile with a .beta.-ketoester 
compound having the structure; 
##STR2## 
wherein R' is a C.sub.1 up to C.sub.8 alkyl, aryl or halide substituted 
alkyl or aryl moiety, 
each R" is independently selected from H, a C.sub.1 up to C.sub.8 alkyl 
moiety, or a halogen, and 
R''' is selected from H, C.sub.1 up to C.sub.4 alkyl moieties, C.sub.4 up 
to C.sub.10 aromatic, heteroaromatic and substituted aromatic moieties, or 
halogens; 
wherein said contacting is carried out in the essential absence of a 
tetraalkyl titanate and at a temperature and for a time sufficient to 
produce the desired product. 
In accordance with an alternate embodiment of the present invention, there 
is provided a method for the functionalization of nucleophiles having the 
structural formula: 
EQU HY--R.sub.X 
wherein Y is selected from nitrogen, oxygen or sulfur; 
wherein R is selected from: 
i) hydroxylated polyesters having a number average molecular weight in the 
range of about 500 up to 10,000, or 
ii) acrylic polymers containing free hydroxyl groups and having a number 
average molecular weight in the range of about 500 up to 10,000; and 
wherein R can also be H when Y is N; and 
wherein x is 1 when Y is 0 or S, and x is 2 wherein Y is N; 
said process comprising contacting said nucleophile with a compound having 
the structure: 
##STR3## 
wherein R' is a C.sub.1 up to C.sub.8 alkyl, aryl or halide substituted 
alkyl or aryl moiety, 
each R" is independently selected from H, a C.sub.1 to C.sub.8 alkyl 
moiety, or a halogen, and 
R''' is selected from H, C.sub.1 up to C.sub.4 alkyl moieties, C.sub.4 up 
to C.sub.10 aromatic, heteroaromatic and substituted aromatic moieties, or 
halogens; 
wherein said contacting is carried out in the essential absence of a 
tetraalkyl titanate and at a temperature and for a time sufficient to 
produce the desired product. 
Nucleophiles contemplated for the use in the practice of the present 
invention include, inter alia, alkanols, alkylamines, alkylthiols, aryl 
alcohols, aryl amines and arylthiols. Alkyl moieties having in the range 
of 1 up to 12 carbon atoms are contemplated, while aryl moieties having in 
the range of 4 up to 12 carbon atoms are contemplated. Exemplary 
nucleophiles of this type include n-butanol, octanol, butyl amine, dibutyl 
amine, aniline, phenol, thiophenol, benzyl alcohol, nitroaniline, 
1-methyl-1-cyclohexanol, and the like. 
Additional nucleophiles contemplated for use in the practice of the present 
invention include allyl alcohols having the structure: 
EQU CR.sup.4 2.dbd.CR.sup.4 --CR.sup.4 2--OH 
wherein each R.sup.4 is independently selected from the group consisting of 
hydrogen and hydrocarbyl radicals having 1 up to 4 carbon atoms. Exemplary 
nucleophiles of this type include allyl alcohol, 3-methyl-2-buten-1-ol, 
2-methyl-2-propen-1-ol, 3-methyl-3-buten-2-ol, and the like. 
Acrylates having the structure: 
##STR4## 
are also contemplated for use in the practice of the present invention. 
Each R.sup.5 is independently selected from hydrogen, methyl or ethyl 
radicals, and n can vary from 1 up to 6. Exemplary acrylate moieties 
satisfying this structure include hydroxyethyl methacrylate, hydroxyethyl 
acrylate, hydroxybutyl methacrylate, hydroxybutyl acrylate, and the like. 
Polyol nucleophiles contemplated for use in the practice of the present 
invention have the general structure: 
EQU HO--(CR.sup.6 2).sub.m --OH 
wherein each R.sup.6 is independently selected from the group consisting of 
hydrogen, hydroxy, and alkylene radicals having 1 up to 4 carbon atoms, 
while m can vary from 2 up to about 12. 
Polymeric nucleophiles contemplated for use in the practice of the present 
invention include 
i) hydroxylated polyesters having a number average molecular weight in the 
range of about 500 up to 10,000 or 
(ii) acrylic polymers containing free hydroxyl groups and having a number 
average molecular weight in the range of about 500 up to 10,000. 
Preferred hydroxylated polyesters have the structure: 
##STR5## 
wherein each R.sup.7 and R.sup.7' is independently selected from H, C.sub.1 
up to C.sub.4 alkyl, hydroxy, or alkoxy of the structure, --OZ, wherein Z 
is a hydrocarbyl moiety having in the range of 1 up to 6 carbon, atoms; 
and 
each R.sup.8 and R.sup.8' is independently selected from 1,2-arylene, 
1,3-arylene, 1,4-arylene or an alkylene moiety of the structure: 
EQU --(CR.sup.9 2).sub.d -- 
wherein each R.sup.9 is independently selected from H, C.sub.1 up to 
C.sub.4 alkyl, hydroxy or alkoxy of the structure --OZ, wherein Z is a 
hydrocarbyl moiety having in the range of 1 up to 6 carbon atoms, and d is 
a whole number which can vary from 0 up to 24; 
a can vary from 1 up to 20; 
b can vary from 2 up to 12; and 
c can vary from 2 up to 12. 
Exemplary materials which conform to this generic formula include 
hydroxylated polyesters having a number average molecular weight in the 
range of about 500 up to 6,000 and comprising at least one dicarboxylic 
moiety selected from the group consisting of phthalic acid, terephthalic 
acid, isophthalic acid, adipic acid, 1,4-cyclohexanedicarboxylic acid, 
1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, and 
esters thereof; and at least one polyol selected from the group consisting 
of ethylene glycol, propylene glycol, pentaerythritol, neopentylglycol, 
2,2,4-trimethyl -1,3-pentanediol, glycerol, 1,1,1-trimethylolpropane, and 
1,1,1-trimethylolethane. 
Preferred acrylic polymers employed in the practice of the present 
invention are polymers prepared from hydroxyethyl methacrylate, 
hydroxyethyl acrylate, 4-hydroxybutyl acrylate and/or 4-hydroxybutyl 
methacrylate with at least one comonomer selected from the group 
consisting of methyl acrylate, ethyl acrylate, propyl acrylate, butyl 
acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, 
and butyl methacrylate. 
.beta.-Ketoester compounds contemplated for use in the practice of the 
present invention are compounds having the structure: 
##STR6## 
wherein R' is a C.sub.1 up to C.sub.8 alkyl aryl or halide substituted 
alkyl or aryl moiety, 
each R" is independently selected from H, a C.sub.1 up to C.sub.8 alkyl 
moiety, or a halogen, and 
R''' is selected from H, C.sub.1 up to C.sub.4 alkyl moieties, C.sub.4 up 
to C.sub.10 aromatic, heteroaromatic and substituted aromatic moieties, or 
halogens. 
Preferred .beta.-ketoesters useful in the practice of the present invention 
include compounds wherein R' is methyl or tertiary butyl, R" is H or a 
C.sub.1 up to C.sub.4 alkyl moiety and R''' is H, a C.sub.1 up to C.sub.4 
alkyl moiety or a chloride radical. 
Presently most preferred .beta.-ketoester moieties for use in the practice 
of the present invention include t-butyl acetoacetate, 2-chloro-t-butyl 
acetoacetate, t-butyl pivaloyl acetate, and t-amyl acetoacetate. Presently 
most preferred acetoacetates are t-butyl acetoacetate and t-butyl pivaloyl 
acetate, because of the ready availability and high reactivity of these 
compounds. 
When t-butyl pivaloyl acetate is employed as the acetoacetylating moiety, a 
particularly preferred nucelophile to employ in the practice of the present 
invention is 2-chloro-4-nitroaniline. This combination of reagents gives 
much more rapid reaction to produce the desired product than does the 
reaction of 2-chloro-4-nitroaniline with methyl pivaloyl acetate. 
The invention reaction can be carried out under a wide variety of 
conditions. For example, reaction can be carried out in the presence or 
absence of solvent. When employed, suitable solvents include aromatic 
hydrocarbons (e.g., toluene, xylene, and the like) esters, e.g., butyl 
acetate, ethyl amyl acetate, ethyl-3-ethoxy propionate, and the like), 
ketones (e.g., methyl isobutyl ketone, methyl amyl ketone, methyl isoamyl 
ketone, ethyl butyl ketone, and the like), as well as any of the above 
solvents used in conjunction with a material capable of azeotroping with 
t-butanol (e.g., cyclohexane). 
When solvent is employed, concentrations of .beta.-ketoester of from about 
0.1 up to 10 moles per liter can be employed, depending on the solubility 
of the nucleophile to be employed. 
The invention process can be carried out at a wide range of temperatures. 
Typical temperatures fall in the range of about 80 up to 200.degree. C., 
with temperatures in the range of about 90 up to 160.degree. C. being 
preferred. 
Reaction times in the range of about 0.5 up to 24 hours are generally 
suitable. Preferably, reaction times in the range of about 0.5 up to 8 
hours are employed. Those of skill in the art recognize that the desired 
reaction time will vary as a function of numerous variables, such as, for 
example, reaction temperature, the desired degree of conversion, the 
particular reactants employed, and so on. 
As specified hereinabove, the process of the present invention is carried 
out in the essential absence of tetraalkyl titanate compounds such as 
those described by Seebach et al in the reference cited above, e.g., in 
the absence of tetraalkyl titantes in amounts in which they are typically 
used to catalyze transesterification reactions. Preferably, the process is 
performed in the absence of transesterification catalysts in general. 
The invention will now be described in greater detail by reference to the 
following nonlimiting examples. 
EXAMPLE 1 
Several methods for functionalization of nucleophiles in accordance with 
the present invention are illustrated below. 
METHOD A 
The preparation of the bis-acetoacetate of neopentyl glycol (NPG) is 
illustrative of this procedure. In a 125 mL Erlenmeyer flask with magnetic 
stirrer and thermometer was placed 10.03 g NPG (0.096 mole), 32.1 g 
tertiary butyl acetoacetate (tBAA; 0.203 mol) and 32 mL xylene. The 
solution was heated with stirring on a hot plate to the boiling point of 
xylene. Once the solution reached 138.degree. C. (ca. 10 min) the solution 
was removed from the hot plate, cooled to room temperature, concentrated in 
vacuo and short-path distilled to yield 22.83 g (87.1%) bis-acetoacetate 
b.p. 145-148.degree. C. (0.05 mm Hg). 
METHOD B 
Another procedure involved heating the alcohol and tBAA, (or 
beta-ketoester) in solvent, in a round-bottom flask with magnetic stirrer, 
5-plate Oldershaw column and still head for removal of the t-butanol 
co-product. For example: a solution of n-octanol (13 g, 0.1 mol), tBAA 
(16.6 g, 0.105 mol) and 50 mL toluene was heated at reflux until the 
theoretical amount of t-butyl alcohol was obtained (ca. 15 min. after 
reflux). The reaction mixture was subsequently concentrated and distilled 
to give 17.8 g (83.2%) octyl acetoacetate b.p. 95-110.degree. C. (1.0 mm 
Hg). 
METHOD C 
This method is a modification of Method B. In a 300 mL, 3-neck flask with 
magnetic stirrer, 5-plate Oldershaw column with still head and 
thermometers in the base and head of the system, was placed 33.52 g tBAA, 
30.1 g phenol, 110 mL xylene and 100 mL cyclohexane. The solution was 
heated to reflux and the t-BuOH/cyclohexane azeotrope removed by 
distillation. Additional cyclohexane can be added to the reaction if 
necessary. Total yield of phenyl acetoacetate from this process was 21.9 g 
(74%). 
Examples of acetoacetylated materials prepared by methods A-C are given in 
Table 1. Examples of other beta-ketoesters prepared by method B are given 
in Table 2. 
TABLE 1 
__________________________________________________________________________ 
Yield of Various Acetoacetylated Materials 
Using t-Butyl Acetoacetate (tBAA) 
mL Yield 
Experimental.sup.a 
Nucleophile.sup.b, grams 
g(tBAA) 
Solvent 
(%) Method 
__________________________________________________________________________ 
TMP 47.5 
171.00 
100 90.sup.d 
B 
TMPD 10.1 
22.4 30 87.sup.c 
A 
NPG 10.0 
32.1 32 87.sup.c 
A 
NPG 159.2 
491.3 
450 81.sup.c 
B 
HEMA.sup.g 16.8 
20.5 65 70 B 
CHDM 9.8 22.1 28 69.sup.c,e 
A 
HNBu.sub.2 7.65 
9.24 25 96 A 
PhOH 34 A 
30.1 
33.5 110/100.sup.f 
74 C 
Ph--NH.sub.2 
10.0 
17.2 25 83 A 
NBuOH 10.0 
21.4 40 87 A 
n-OctOH 13.0 
16.6 50 83 B 
Ph--CH.sub.2 OH 
10.8 
16.6 50 89 B 
Ester diol 204 
10.2 
16.2 60 88.sup.c 
B 
p(NO.sub.2)PhNH.sub.2 
13.8 
16.2 50 86 B 
1-Me-Cyclohexan-1-ol 
11.4 
16.2 50 83 B 
1-Me-2-buten-1-ol 
8.6 16.2 50 97 B 
__________________________________________________________________________ 
.sup.a Refers to the description of the experimental method set forth in 
Example 1. 
.sup.b Abbreviations used: TMPD = 2,2,4trimethyl-1-1,3-pentanediol TMP = 
trimethylolpropane NPG = neopentyl glycol or 2,2dimethyl-1,3-propanediol 
HEMA = hydroxyethyl methacrylate CHDM = cyclohexane1,4-dimethanol 
HNBu.sub.2 = dibutyl amine Ester diol 204 (sold by Union Carbide). Also 
known as HPHP--hydroxy pivaloyl hydroxy pivaloate 
.sup.c Yield of bisacetoacetate for TMPD, NPG, CHDM and Ester diol 204. 
.sup.d Yield of trisacetoacetate for TMP. 
.sup.e Yield of crystalline material, some cis isomer lost in 
recrystallization. 
.sup.f 110 mL xylene, 100 mL cyclohexane. 
.sup.g Reaction also contained 67 mg benzoquinone and 137 mg BHT. 
TABLE 2 
__________________________________________________________________________ 
Yield for Reaction of 
##STR7## 
With Various Nucleophiles by Method B 
g 
R" (keto- 
mL 
Nuc (g) C(1) 
C(2) 
C(3) R"' 
R' ester) 
(solvent) 
Yield 
__________________________________________________________________________ 
p-NO.sub.2 PhNH.sub.2 (8.3) 
H.sub.3 
H.sub.3 
H, H, CH.sub.3 
H CH.sub.3 
10.7 
60 91% 
PhCH.sub.2 OH (10.8) 
H.sub.3 
H.sub.3 
H, H, CH.sub.3 
H CH.sub.3 
13.3 
60 68% 
PhCH.sub.2 OH (4.8) 
H.sub.3 
H.sub.3 
H.sub.3 
Cl CH.sub.3 
2.7 50 81% 
OctOH (3.3) 
H.sub.3 
H.sub.3 
H.sub.3 
Cl CH.sub.3 
5.5 50 98% 
OctOH (7.0) 
H.sub.3 
H.sub.3 
H.sub.3 
CH.sub.3 
CH.sub.3 
3.3 60 88% 
nBuOH (0.85) 
H.sub.3 
H.sub.3 
H.sub.3 
H C(CH.sub.3).sub.3 
0.93 
10 91% 
2-Cl-4-(NO.sub.2 ) 
H.sub.3 
H.sub.3 
H.sub.3 
H C(CH.sub.3).sub.3 
1.32 
20 95% 
PhNH.sub.2 (1.36) 
n-OctOH (0.937) 
H.sub.3 
H.sub.3 
H.sub.3 
H CH.sub.2 Cl 
1.11 
10 54% 
__________________________________________________________________________ 
The results presented in Tables 1 and 2 demonstrate the generality of the 
invention process for the preparation of a wide variety of low molecular 
weight acetoacetated materials. The generality of the invention process 
for polymeric nucleophiles is demonstrated in Examples 3 and 4. 
EXAMPLE 2 
The following procedure was used to determine the relative rates of 
reaction of various nucleophiles with the beta-ketoesters. A solution of 
4.7-5.4 mmol acetoacetate (ketoester), nucleophile (4.9-50 mmol) and 
p-dichlorobenzene internal standard (450-500 mg) diluted to 10 mL with 
p-xylene was placed in a flask with condenser and N.sub.2 inlet. The 
apparatus was placed in a constant temperature bath, samples periodically 
withdrawn and the extent of reaction assessed by gas chromatography. Rate 
data obtained by this method are given in Tables 3 and 4. In addition, the 
advantages of the invention process for the reaction of t-butyl pivaloyl 
acetate with 2-chloro-4-nitroaniline are shown in Table 5. 
TABLE 3 
______________________________________ 
Rate Constants for Reactions of QOAcAc 
With n-BuOH at 91.85.degree. C. 
Q k .times. 10.sup.4a 
[nBuOH].sup.b 
[QOAcAc].sup.c 
______________________________________ 
tBu 1.716 0.492 0.474 
tBu 1.662 2.623 0.475 
tBu.sup.d 
1.859 1.027 0.472 
tBu 1.559 0.174 0.068 
Et 0.102 0.526 0.473 
Et 0.136 4.987 0.477 
Me 0.097 0.611 0.551 
iBu 0.138 1.068 0.474 
iPr 0.140 1.070 0.537 
HC(iPr).sub.2 
0.083 1.046 0.477 
tAm 1.460 1.072 0.495 
TKD 1.07 
______________________________________ 
.sup.a First-order rate constant in sec.sup.-1. 
.sup.b Molar concentration of nBuOH. 
.sup.c Molar concentration of acetoacetate. 
.sup.d Acetoacetate distilled prior to use. 
TABLE 4 
______________________________________ 
First-Order Rate Constants (In Sec.sup.-1) For Reaction 
of Various Beta-Ketoesters With Nucleophiles 
______________________________________ 
A. Rate of Reaction of 2-Chloro Acetoacetates with 
n-Octanol at 114.9.degree. C. 
Acetoacetate 
[AcAc] [n-OctOH] k.sub.1 .times. 10.sup.6 
______________________________________ 
t-Butyl 0.48 0.72 8.55 
t-Butyl 0.48 2.88 8.62 
Ethyl 0.48 2.88 2.93 
______________________________________ 
B. Rate of Reaction of 2-Methyl Acetoacetates with 
n-Octanol at 114.9.degree. C. 
Acetoacetate 
[AcAc] [n-OctOH] k.sub.1 .times. 10.sup.6 
______________________________________ 
t-Butyl 0.48 0.72 24.3 
t-Butyl 0.48 2.88 29.7 
Ethyl 0.48 2.88 3.7 
______________________________________ 
C. Rate of Reaction of 4-Chloro Acetoacetates with 
n-Octanol at 91.9.degree. C. 
Acetoacetate 
[AcAc] [n-OctOH] k.sub.1 .times. 10.sup.4 
______________________________________ 
t-Butyl 0.48 2.88 3.00 
t-Butyl 0.48 0.72 2.78 
Ethyl 0.48 0.72 0.21 
Ethyl 0.48 2.88 0.27 
______________________________________ 
D. Rate of Reaction of Pivaloyl Acetates with 
n-BuOH at 91.9.degree. C. 
Ester k.sub.1 .times. 10.sup.4 
______________________________________ 
t-Bu 1.54 
Me 0.13 
______________________________________ 
TABLE 5 
______________________________________ 
Percent Conversion to C1-Nitro-Anilide with 
Methyl and t-Butyl Pivaloyl Acetates 
##STR8## 
% Conversion 
Time (min) Q = Me Q = tBu 
______________________________________ 
90 4.2 26.0 
230 10.0 36.0 
480 14.0 45.5 
1400 24.0 60.0 
______________________________________ 
The rate data presented in Tables 3 and 4 demonstrate the advantage of the 
invention process relative to prior art processes employing methyl or 
ethyl acetoacetate. Rate enhancements of an order of magnitude and higher 
are routinely observed for the invention process relative to prior art 
processes. 
The percent conversion results summarized in Table 5 demonstrate that 
t-butyl pivaloyl acetate gives much higher yields of desired product than 
does methyl pivaloyl acetate. At all time points analyzed, the yield of 
product formed from t-butyl pivaloyl acetate is more than double the yield 
of product obtained from methyl pivaloyl acetate. 
EXAMPLE 3 
ACETOACETYLATION OF POLYESTER RESINS 
RUN NO. 1 
To a solution of 450.3 g of polyester resin comprised of 44.2% neopentyl 
glycol (NPG), 3.0% trimethylolpropane (TMP), 28.9% dimethylcyclohexane 
dicarboxylate (DMCD), 23.9% isophthalic acid with molecular weight of 
858-1297 and a hydroxyl number of about 210 in xylene solvent (85% solids) 
at 140.degree. C. was added 120.0 g tBAA. The t-butyl alcohol begin to 
distill from the reaction immediately and the process was complete in 2 
hours. When an identical polyester solution was treated with either ethyl 
or methyl acetoacetate, the rate of acetoacetylation (as noted by the 
evolution of alcohol) was 2-6 hours slower, even if 0.1 wt % of a 
dibutyltin oxide catalyst was used. Analysis of the resultant polyesters 
by proton nuclear magnetic resonance spectroscopy (.sup.1 H-NMR) showed 
that the polyesters acetoacetylated with methyl acetoacetate (MAA) or 
ethyl acetoacetate (EAA) and catalyst had been reduced in molecular 
weight, while no such polyester breakdown was noted for the reaction with 
tBAA. 
RUN NO. 2 
In another experiment 102.35 g of a high-solids polyester coating resin 
comprised of 2,2,4-trimethyl -1,3-propanediol (TMPD; 54 wt %), TMP (4.7 
%), isophthalic acid (22 %) and adipic acid (19.3 %) with a hydroxyl 
number of about 170 and molecular weight 900-1,100 was placed in 500 mL 
3-neck flask with addition funnel, 5-plate Oldershaw column with still 
head and thermometers in the base and head. The resin was diluted to 69% 
solids with xylene, heated to 120.degree. C., 25.15 g of tBAA were added 
and the resultant t-butanol was removed by distillation over a 2 hr. 
period to obtain an acetoacetylated resin in which 50% of the hydroxyl end 
groups were acetoacetylated. The ratio of tBAA to polyester could be 
altered to produce material with 11%, 18%, 25% or 85% acetoacetylation. 
RUN NO. 3 
In another experiment 392.8 g of a high-solids coating resin comprised of 
35.3 wt % isophthalic acid and 64.7 wt % TMPD with a hydroxyl number of 
about 285-265 and molecular weight 600-800 was placed in a 3-neck flask 
with addition funnel, mechanical stirrer, steam-heated reflux column 
topped with a Dean-Stark trap with condenser. The neat resin was heated to 
150.degree. C. and 272.1 g tBAA was added drop-wise over a period of 1.5 
hr. Two hours after the addition was begun 94% of the theoretical amount 
of t-butyl alcohol was obtained. Analysis of the resulting resin by .sup.1 
H-NMR spectroscopy again indicated the production of an acetoacetylated 
resin with 89% of the hydroxyls acetoacetylated. 
RUN NO. 4 
In a 250 mL round bottom flask with 6" Vigreaux column, still head, 
magnetic stirrer and N.sub.2 inlet was placed 25.48 g of a polyester 
comprised of NPG and terephthalic acid with a hydroxyl number of about 45 
and number average molecular weight of about 3089, 1.92 g tBAA and 35 mL 
n-butyl acetate. The solution was warmed to reflux and solvent removed 
until the head temperature reached 110.degree. C. (approximately 45 
minutes). NMR spectroscopic analysis of the resulting concentrated 
solution showed that approximately 60% of the end groups had been 
acetoacetylated. 
The above runs demonstrate that the invention process can be used for the 
acetoacetylation of a variety of hydroxylated polyester resins. The degree 
of acetoacetylation is readily controlled by varying the t-butyl 
acetoacetate/polyester ratio. 
EXAMPLE 4 
ACETOACETYLATION OF ACRYLIC RESINS 
RUN NO. 1 
In a 2L 3-neck flask with magnetic stirrer, 5-plate Oldershaw column with 
still head and nitrogen inlet was placed 517.4 g of an acrylic polymer 
with acid number 10.6, and hydroxyl number of about 169, in butyl acetate 
as a 61.3 % solid solution. A 112.8 g sample of tBAA was placed in the 
flask and the solution was heated to reflux with removal of t-butanol over 
a period of 50 min. The resulting acetoacetylated polymer was identical by 
NMR spectroscopy with one prepared by reaction of the polymer with 
diketene (ca. 50% acetoacetylation). An identical material was also 
obtained if the reaction was carried out on the polymer in methyl isobutyl 
ketone solvent. 
RUN NO. 2 
In another experiment 157 g of a 60% solids solution in 
ethoxyethylpropionate (EEP) of an acrylic terpolymer prepared from 48 wt % 
of methylmethacrylate, 29 wt % butyl methacrylate and 22 wt % hydroxyethyl 
methacrylate was acetoacetylated with 12.8 g t-butyl acetoacetate (tBAA) 
by heating the solution to 160.degree. C. and removing the resulting 
t-butanol by distillation through a 5-plate Oldershaw column. This 
produced a material in which approximately 50% of the available hydroxyls 
had been acetoacetylated. This same resin was acetoacetylated so as to 
acetoacetylate about 85% of the available hydroxyls by using 188 g of the 
resin solution and 26.0 g tBAA. 
RUN NO. 3 
Using the same method as described in Run No. 2, 155 g of a 60% solids 
solution in EEP of an acrylic copolymer prepared from 70 mol % methyl 
methacrylate and 30 mol % hydroxyethyl methacrylate was acetoacetylated 
with 21.76 g tBAA to produce a polymer in which approximately 50% of the 
hydroxyls had been acetoacetylated. This same polymer was acetoacetylated 
so as to acetoacetylate about 85% of the hydroxyls by treating 166.7 g of 
the resin solution with 36.9 g tBAA. 
The above runs demonstrate that the invention process can be used for the 
acetoacetylation of hydroxylated acrylic resins. As was the case with 
hydroxylated polyesters as reactive nucleophiles, it is possible to 
control the degree of acetoacetylation by varying the t-butyl 
acetoacetate/acrylic resin ratio. 
The invention has been described in detail with particular reference to 
preferred embodiments thereof, but it will be understood that variations 
and modifications can be effected within the spirit and scope of the 
invention.