COMPOSITION COMPRISING TITANIUM OR ZIRCONIUM ALKOXIDE OR ARYLOXIDE AND USE THEREOF

Abstract

The invention relates to a composition comprising a titanium or zirconium alkoxide or aryloxide, wherein the alkoxy group in the titanium or zirconium alkoxide is a group of formula R-0.sup.− wherein R is an alkyl group having 1 to 4 carbon atoms and the aryloxy group in the titanium or zirconium aryloxide is a group of formula Ar-0.sup.− wherein Ar is an aryl group having 6 to 12 carbon atoms, and wherein the composition additionally comprises 0.1 to 50 wt. % of an organic carbonate, based on the total weight of the composition. Further, the invention relates to a process for preparing such composition, comprising blending such titanium or zirconium alkoxide or aryloxide with an organic carbonate in such amounts that the resulting composition comprises 0.1 to 50 wt. % of the organic carbonate, based on the total weight of the composition. Still further, the invention relates to a process for preparing an aromatic carbonate, such as a diaryl carbonate, using said composition comprising a titanium or zirconium alkoxide or aryloxide; and to a process for making a polycarbonate from the diaryl carbonate thus prepared.

Claims

1. A composition comprising a titanium or zirconium alkoxide or aryloxide, wherein the alkoxy group in the titanium or zirconium alkoxide is a group of formula R—O.sup.− wherein R is an alkyl group having 1 to 4 carbon atoms and the aryloxy group in the titanium or zirconium aryloxide is a group of formula Ar—O.sup.− wherein Ar is an aryl group having 6 to 12 carbon atoms, and wherein the composition additionally comprises 0.1 to 50 wt. % of an organic carbonate, based on the total weight of the composition.

2. A composition according to claim 1, wherein the amount of the organic carbonate is 0.1 to 20 wt. %, preferably 0.5 to 10 wt. %, more preferably 1 to 6 wt. %, based on the total weight of the composition.

3. A composition according to claim 1, wherein the organic carbonate is of formula ROC(═O)OR′, wherein R and R′ may be the same or different and are each an alkyl or aryl group.

4. A composition according to claim 3, wherein the organic carbonate is a dialkyl carbonate, preferably diethyl carbonate.

5. A composition according to claim 1, wherein the alkyl group having 1 to 4 carbon atoms is selected from the group consisting of methyl, ethyl, n-propyl and isopropyl.

6. A process for preparing a composition comprising a titanium or zirconium alkoxide or aryloxide, wherein the alkoxy group in the titanium or zirconium alkoxide is a group of formula R—O.sup.− wherein R is an alkyl group having 1 to 4 carbon atoms and the aryloxy group in the titanium or zirconium aryloxide is a group of formula Ar—O.sup.− wherein Ar is an aryl group having 6 to 12 carbon atoms, comprising blending the titanium or zirconium alkoxide or aryloxide with an organic carbonate in such amounts that the resulting composition comprises 0.1 to 50 wt. % of the organic carbonate, based on the total weight of the composition.

7. A process for preparing an aromatic carbonate, comprising reacting a dialkyl carbonate or an alkyl aryl carbonate with an aryl alcohol or an alkyl aryl carbonate, resulting in an aromatic carbonate which is an alkyl aryl carbonate or a diaryl carbonate, wherein the composition comprising a titanium or zirconium alkoxide or aryloxide of claim 1 or prepared in accordance with the process of claim 6 is mixed with an organic carbonate or an aryl alcohol, wherein the aryl alcohol is preferably phenol, and the mixture thus obtained is contacted with said dialkyl carbonate or alkyl aryl carbonate and aryl alcohol or alkyl aryl carbonate to catalyze the preparation of the aromatic carbonate.

8. A process according to claim 7, wherein the organic carbonate that is mixed with the composition comprising a titanium or zirconium alkoxide or aryloxide is of formula ROC(═O)OR′, wherein R and R′ may be the same or different and are each an alkyl or aryl group.

9. A process according to claim 8, wherein the organic carbonate is a dialkyl carbonate, preferably diethyl carbonate.

10. A process according to claim 7, wherein the organic carbonate as contained in the composition comprising a titanium or zirconium alkoxide or aryloxide is the same as the organic carbonate with which said composition is mixed.

11. A process according to claim 7, wherein the step of mixing an organic carbonate with the composition comprising a titanium or zirconium alkoxide or aryloxide of any one of claims 1-5 or prepared in accordance with the process of claim 6 is preceded by a step comprising transporting said composition.

12. A process according to claim 11, wherein the temperature during transport is of from −10 to 50° C., preferably 0 to 40° C.

13. A process for making a polycarbonate, comprising reacting a dihydroxy aromatic compound with a diaryl carbonate prepared in accordance with the process of claim 7.

14. A process for making a polycarbonate, comprising preparing a diaryl carbonate in accordance with the process of claim 7, and reacting a dihydroxy aromatic compound with the diaryl carbonate thus obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0026] The composition of the present invention comprises a titanium or zirconium alkoxide or aryloxide, wherein the alkoxy group in the titanium or zirconium alkoxide is a group of formula R—O.sup.− wherein R is an alkyl group having 1 to 4 carbon atoms and the aryloxy group in the titanium or zirconium aryloxide is a group of formula Ar—O.sup.− wherein Ar is an aryl group having 6 to 12 carbon atoms.

[0027] While any processes and/or compositions embodying the present invention are described in terms of “comprising”, “containing” or “including” various described features and/or steps, they can also “consist essentially of” or “consist of” the various described features and steps. Thus, while the composition and processes of the present invention are described in terms of “comprising”, “containing” or “including” one or more various described components and steps, respectively, they can also “consist essentially of” or “consist of” said one or more various described components and steps, respectively.

[0028] Within the present specification, said titanium or zirconium alkoxide or aryloxide means a titanium or zirconium containing compound which, in addition to the metal, contains one or more ligands, which may be the same or different, wherein one or more of the ligands is or are an alkoxy group and/or an aryloxy group and wherein any remaining ligands are selected from the group consisting of arylalkoxy, alkylaryloxy, alkyl, arylalkyl, aryl, alkylaryl, hydroxide, carboxylate, carbonate and halide groups. Preferably, all of said ligands are the same and are an alkoxy group and/or an aryloxy group, more preferably an alkoxy group or an aryloxy group. More preferably, the titanium or zirconium alkoxide is of formula M(OR).sub.4, wherein M=Ti or Zr, most preferably Ti, and wherein R is an alkyl group having 1 to 4 carbon atoms, whereas the titanium or zirconium aryloxide is of formula M(OAr).sub.4, wherein M=Ti or Zr, most preferably Ti, and wherein Ar is an aryl group having 6 to 12 carbon atoms.

[0029] Within the present specification, an “arylalkoxy” group is a group of formula Ar—R—O.sup.− wherein Ar is an aryl group and R is an alkyl group. An “aryloxy” group is a group of formula Ar—O.sup.− wherein Ar is an aryl group. An “alkylaryloxy” group is a group of formula R—Ar—O.sup.− wherein R is an alkyl group and Ar is an aryl group. An “alkyl” group is of formula R. An “arylalkyl” group is a group of formula Ar—R wherein Ar is an aryl group and R is an alkyl group. An “aryl” group is a group of formula Ar. An “alkylaryl” group is a group of formula R—Ar wherein R is an alkyl group and Ar is an aryl group. A “hydroxide” group is a group of formula HO.sup.−. A carboxylate group is a group of formula R′—C(═O)—O.sup.− wherein R′ may be an alkyl, arylalkyl, aryl or alkylaryl group. For example, said carboxylate group may be an acetoxy group. A carbonate group is a group of formula .sup.−O—C(═O)—O.sup.−. These alkyl and aryl groups may be substituted or unsubstituted. Further, the alkyl group may be a branched or linear, preferably linear, C.sub.1-C.sub.6 alkyl group, preferably C.sub.1-C.sub.4 alkyl group, more preferably C.sub.1-C.sub.3 alkyl group (methyl, ethyl, n-propyl or isopropyl group), more preferably C.sub.1-C.sub.2 alkyl group (methyl or ethyl group), most preferably C.sub.2 alkyl group (ethyl group). The aryl group may be a phenyl group. A halide group may be selected from the group consisting of fluoride (F.sup.−), chloride (Cl.sup.−), bromide (Br.sup.−) and iodide (I.sup.−).

[0030] Preferably, said alkyl group for the alkoxy group in the titanium or zirconium alkoxide which may be contained in the composition of the present invention, has 1 to 3 carbon atoms. Further, preferably, said alkyl group is selected from the group consisting of methyl, ethyl, n-propyl and isopropyl, more preferably from the group consisting of ethyl, n-propyl and isopropyl, most preferably from the group consisting of ethyl and isopropyl. If the alkyl group is n-propyl, the oxygen atom is bonded to the first, primary carbon atom of the propyl group. If the alkyl group is isopropyl, the oxygen atom is bonded to the second, secondary carbon atom of the propyl group. More preferably, said alkyl group is selected from the group consisting of methyl, ethyl and n-propyl. Even more preferably, said alkyl group is methyl or ethyl. Most preferably, said alkyl group is ethyl. As mentioned above, preferably, the titanium or zirconium alkoxide is of formula M(OR).sub.4, wherein M=Ti or Zr, most preferably Ti, and wherein R is said alkyl group. Most preferably, the composition of the present invention comprises titanium tetraethoxide.

[0031] In the present invention, the aryloxy group in the titanium or zirconium aryloxide is a group of formula Ar—O.sup.− wherein Ar is an aryl group having 6 to 12 carbon atoms. Preferably, said aryl group is phenyl. As mentioned above, preferably, the titanium or zirconium aryloxide is of formula M(OAr).sub.4, wherein M=Ti or Zr, most preferably Ti, and wherein Ar is said aryl group. A particular suitable example of a titanium or zirconium aryloxide is titanium tetraphenoxide.

[0032] In addition to the above-described titanium or zirconium alkoxide or aryloxide, the composition of the present invention comprises an organic carbonate. It has surprisingly appeared that by adding an organic carbonate to a titanium or zirconium alkoxide or aryloxide, the melting temperature of the resulting composition (blend) is reduced as compared to the melting point of the titanium or zirconium alkoxide or aryloxide alone, such that the composition can be held as a liquid at a relatively low temperature, thereby enabling transport and storage of titanium or zirconium alkoxide or aryloxide catalyst in liquid form at a relatively low temperature.

[0033] Preferably, the organic carbonate is an organic carbonate which is a liquid in the standard state, that is to say at a standard temperature of 25° C. and a standard pressure of 100 kPa.

[0034] As to the chemical composition of the organic carbonate, any organic carbonate may be used. For example, the organic carbonate may be a compound of formula ROC(═O)OR′, wherein R and R′ may be the same or different and are each an alkyl or aryl group, in particular a compound selected from the group consisting of dialkyl carbonates and alkyl aryl carbonates. Said alkyl group may have 1 to 4, suitably 1 to 3 carbon atoms. Suitably, said alkyl group is a methyl group or ethyl group, more suitably an ethyl group. Said aryl group may have 6 to 12 carbon atoms. Suitably, said aryl group is a phenyl group. Suitable examples of said alkyl aryl carbonate are methyl phenyl carbonate and ethyl phenyl carbonate. Preferably, said organic carbonate of formula ROC(═O)OR′ is a dialkyl carbonate wherein R and R′ are C.sub.1-4 alkyl groups, preferably C.sub.1-3 alkyl groups. More preferably, said dialkyl carbonate is dimethyl carbonate or diethyl carbonate, most preferably diethyl carbonate. Further, the organic carbonate may be a cyclic carbonate, like an alkylene carbonate, for example an alkylene carbonate having 3 to 6, suitably 3 to 4 carbon atoms. Suitable examples of alkylene carbonates are ethylene carbonate and propylene carbonate.

[0035] The amount of the organic carbonate in the composition of the present invention is not essential and is 0.1 to 50 wt. %, based on the total weight of the composition. Accordingly, the composition of the present invention may comprise 50 to 99.9 wt. % of the titanium or zirconium alkoxide or aryloxide, based on the total weight of the composition. Preferably, the composition of the present invention comprises 0.1 to 20 wt. %, more preferably 0.5 to 10 wt. %, most preferably 1 to 6 wt. % of the organic carbonate, based on the total weight of the composition. Accordingly, the composition of the present invention preferably comprises 70 to 99.9 wt. %, more preferably 90 to 99.5 wt. %, most preferably 94 to 99 wt. % of the titanium or zirconium alkoxide or aryloxide, based on the total weight of the composition. The minimum amount of organic carbonate needed to keep the composition of the present invention as a liquid depends on the temperature at which said composition is to be transported and/or stored. The lower said temperature, the more organic carbonate is needed. Furthermore, this depends on the nature of the organic carbonate.

[0036] The amount of the organic carbonate in the composition of the present invention is at least 0.1 wt. %, based on the total weight of the composition, preferably at least 0.5 wt. %, more preferably at least 1 wt. %, more preferably at least 1.5 wt. %, more preferably at least 2 wt. %, more preferably at least 2.5 wt. %, more preferably at least 3 wt. %, more preferably at least 3.5 wt. %, more preferably at least 4 wt. %, more preferably at least 4.5 wt. %, most preferably at least 5 wt. %. Further, said amount may be at least 6 wt. %, or at least 7 wt. %, or at least 8 wt. %.

[0037] The amount of the organic carbonate in the composition of the present invention is at most 50 wt. %, based on the total weight of the composition, preferably at most 40 wt. %, more preferably at most 30 wt. %, more preferably at most 25 wt. %, more preferably at most 20 wt. %, more preferably at most 15 wt. %, more preferably at most 10 wt. %, most preferably at most 8 wt. %. Further, said amount may be at most 7 wt. %, or at most 6 wt. %.

[0038] In the context of the present invention, in a case where a composition embodying the present invention comprises two or more components, these components are to be selected in an overall amount not to exceed 100 wt. %.

[0039] Further, the present invention relates to a process for preparing a composition comprising a titanium or zirconium alkoxide or aryloxide, wherein the alkoxy group in the titanium or zirconium alkoxide is a group of formula R—O.sup.− wherein R is an alkyl group having 1 to 4 carbon atoms and the aryloxy group in the titanium or zirconium aryloxide is a group of formula Ar—O.sup.− wherein Ar is an aryl group having 6 to 12 carbon atoms, comprising blending the titanium or zirconium alkoxide or aryloxide with an organic carbonate in such amounts that the resulting composition comprises 0.1 to 50 wt. % of the organic carbonate, based on the total weight of the composition.

[0040] The composition of the present invention comprising a titanium or zirconium alkoxide or aryloxide and an organic carbonate may be prepared in any way. For example, solid titanium or zirconium alkoxide or aryloxide may be converted to liquid titanium or zirconium alkoxide or aryloxide by heating, before blending with the organic carbonate. Alternatively, solid titanium or zirconium alkoxide or aryloxide may be blended with the organic carbonate, followed by heating to obtain a liquid composition. The foregoing 2 options may be applicable if titanium or zirconium alkoxide or aryloxide has solidifed after it has been manufactured. However, the composition of the present invention may also be prepared in the last phase of the process for manufacturing the titanium or zirconium alkoxide or aryloxide, for example when it is still a liquid directly after it has been manufactured (e.g. freshly distilled). For example, the composition may be prepared by blending liquid titanium or zirconium alkoxide or aryloxide with the organic carbonate. Preferably, the composition of the present invention is prepared at the manufacturing site where the titanium or zirconium alkoxide or aryloxide is manufactured, so that a liquid blend can be made prior to transport and/or storage thereof.

[0041] Further, the present invention relates to a process for preparing an aromatic carbonate, comprising reacting a dialkyl carbonate or an alkyl aryl carbonate with an aryl alcohol or an alkyl aryl carbonate, resulting in an aromatic carbonate which is an alkyl aryl carbonate or a diaryl carbonate, wherein the above-mentioned composition comprising a titanium or zirconium alkoxide or aryloxide or the composition comprising a titanium or zirconium alkoxide or aryloxide prepared in accordance with the above-mentioned process is mixed with an organic carbonate or an aryl alcohol, wherein the aryl alcohol is preferably phenol, preferably with an organic carbonate, and the mixture thus obtained is contacted with said dialkyl carbonate or alkyl aryl carbonate and aryl alcohol or alkyl aryl carbonate to catalyze the preparation of the aromatic carbonate. Accordingly, the present invention also relates to a process for preparing an aromatic carbonate, comprising preparing a composition comprising a titanium or zirconium alkoxide or aryloxide in accordance with the above-mentioned process, mixing said composition with an organic carbonate or an aryl alcohol, wherein the aryl alcohol is preferably phenol, preferably with an organic carbonate, and contacting the mixture thus obtained with a dialkyl carbonate or alkyl aryl carbonate and aryl alcohol or alkyl aryl carbonate to catalyze the preparation of the aromatic carbonate which is an alkyl aryl carbonate or a diaryl carbonate. The embodiments and preferences as described above with reference to the composition comprising a titanium or zirconium alkoxide or aryloxide of the present invention and the process for preparing the same also apply to such composition used in and to such composition preparation step of, respectively, the aromatic carbonate preparation process of the present invention.

[0042] In the aromatic carbonate preparation process of the present invention, the alkyl group in the dialkyl carbonate and alkyl aryl carbonate may have 1 to 4, suitably 1 to 3 carbon atoms. Suitably, said alkyl group is a methyl group or ethyl group, more suitably an ethyl group. Further, in the aromatic carbonate preparation process of the present invention, the aryl group in the aryl alcohol, alkyl aryl carbonate and diaryl carbonate may have 6 to 12 carbon atoms. Preferably, said aryl group is a phenyl group. Therefore, preferably, said aryl alcohol is phenol and said diaryl carbonate is diphenyl carbonate. Suitable examples of said alkyl aryl carbonate are methyl phenyl carbonate and ethyl phenyl carbonate. Preferably, said dialkyl carbonate is of formula ROC(═O)OR′, wherein R and R′ may be the same or different and are C.sub.1-4 alkyl groups, preferably C.sub.1-3 alkyl groups. More preferably, said dialkyl carbonate is dimethyl carbonate or diethyl carbonate, most preferably diethyl carbonate. Further, preferably, in the aromatic carbonate preparation process of the present invention, a dialkyl carbonate is reacted with an aryl alcohol resulting in the corresponding alkyl aryl carbonate.

[0043] Preferably, in the aromatic carbonate preparation process of the present invention, the organic carbonate that may be mixed with the composition comprising a titanium or zirconium alkoxide or aryloxide is of formula ROC(═O)OR′, wherein R and R′ may be the same or different and are each an alkyl or aryl group, in particular a compound selected from the group consisting of dialkyl carbonates and alkyl aryl carbonates. More preferably, said organic carbonate is a dialkyl carbonate, preferably diethyl carbonate. The embodiments and preferences as described above with reference to the organic carbonate as contained in the composition comprising a titanium or zirconium alkoxide or aryloxide of the present invention also apply to the organic carbonate with which the latter composition may be mixed as part of the aromatic carbonate preparation process of the present invention. Preferably, the organic carbonate as contained in the composition comprising a titanium or zirconium alkoxide or aryloxide is the same as the organic carbonate with which said composition is mixed.

[0044] Generally, between preparing the composition comprising a titanium or zirconium alkoxide or aryloxide of the present invention and the mixing thereof with an organic carbonate or an aryl alcohol as part of the aromatic carbonate preparation process of the present invention, the composition comprising a titanium or zirconium alkoxide or aryloxide has to be transported to and optionally stored at the location of aromatic carbonate preparation. Therefore, suitably, the step of mixing an organic carbonate or an aryl alcohol with the composition comprising a titanium or zirconium alkoxide or aryloxide is preceded by a step comprising transporting said composition, in particular transporting said composition to and/or at the location of aromatic carbonate preparation, for example to the location of aromatic carbonate preparation, and optionally storing said composition at such location. Such transport, like transporting at the location of aromatic carbonate preparation, for example covers transport of said composition from a storage tank to a reactor on the same site which transport may take place in a pipe. Further, suitably, the temperature during such transport and optionally storage is of from −10 to 50° C., preferably 0 to 40° C. In the present invention, the combination with an organic carbonate surprisingly and advantageously has resulted in a reduction of the melting temperature of the titanium or zirconium alkoxide or aryloxide, such that the titanium or zirconium alkoxide or aryloxide can be held as a liquid at a relatively low temperature, thereby enabling transport and storage of titanium or zirconium alkoxide or aryloxide catalyst in liquid form in a relatively broad temperature range.

[0045] To complete the conversion of a dialkyl carbonate and an aryl alcohol into a diaryl carbonate through the intermediate formation of an alkyl aryl carbonate, a series of two or three, preferably three, reactive distillation columns in total may be applied. The various embodiments as disclosed in above-mentioned WO2011067263, disclosing a process wherein three reactive distillation columns are used, may be applied to the present aromatic carbonate preparation process. The disclosure of WO2011067263 is herein incorporated by reference.

[0046] The pressures in said three reactive distillation columns may vary within wide limits. The pressure at the top of the first reactive distillation column may be 2 to 7 bar, preferably 2.5 to 5 bar. The pressure at the top of the second reactive distillation column may be 0.1 to 3 bar, preferably 0.3 to 1.5 bar. The pressure at the top of the third reactive distillation column may be 10 to 600 mbar, preferably 20 to 500 mbar. Preferably, the pressure at the top of the first reactive distillation column is higher than that of the second reactive distillation column which in turn is higher than that of the third reactive distillation column.

[0047] The temperatures in said three reactive distillation columns may also vary within wide limits. The temperature at the bottom of the first, second and third reactive distillation columns may be 50 to 350° C., preferably 120 to 280° C., more preferably 150 to 250° C., most preferably 160 to 240° C.

[0048] The catalyst in one or more of said three reactive distillation columns may be the titanium or zirconium alkoxide or aryloxide as contained in the composition comprising a titanium or zirconium alkoxide or aryloxide of the present invention. This is a homogeneous catalyst. In addition, a heterogeneous catalyst may be used, especially in the first of these reactive distillation columns.

[0049] Still further, the present invention relates to a process for making a polycarbonate from a diaryl carbonate prepared in accordance with the aromatic carbonate preparation process of the present invention. Accordingly, the present invention relates to a process for making a polycarbonate, comprising reacting a dihydroxy aromatic compound with a diaryl carbonate prepared in accordance with the above-described aromatic carbonate preparation process. Further, accordingly, the present invention relates to a process for making a polycarbonate, comprising preparing a diaryl carbonate in accordance with the above-described aromatic carbonate preparation process, and reacting a dihydroxy aromatic compound with the diaryl carbonate thus obtained. The embodiments and preferences as described above with reference to the aromatic carbonate preparation process of the present invention also apply to said diaryl carbonate preparation step of the polycarbonate make process of the present invention.

[0050] Further, preferably, said dihydroxy aromatic compound is bisphenol A, which is 4,4′-(propan-2-ylidene)diphenol. The production of polycarbonate by the polymerisation of diaryl carbonate with an aromatic dihydroxy compound, such as bisphenol A, is well known. See for example U.S. Pat. No. 5,747,609, WO2005026235 and WO2009010486, the disclosures of which are herein incorporated by reference.

[0051] The invention is further illustrated by the following Examples.

EXAMPLES

[0052] In the present Examples, pure titanium tetraethoxide (Ti(OEt).sub.4; 99.7% purity as measured by TiO.sub.2 content), which is a crystallized solid in the standard state and has a melting point of 54° C., was mixed with dry diethyl carbonate (DEC) or dimethyl carbonate (DMC), said dry DEC or DMC having a water content of less than 10 ppmw, at various Ti(OEt).sub.4:DEC or Ti(OEt).sub.4:DMC blend weight ratios. Then the solid/liquid phase behavior of the resulting blend was studied and monitored over time.

[0053] Before blending with the dry DEC or DMC, the solid Ti(OEt).sub.4 was first heated to about 60° C. to fully melt it. Then the dry DEC or DMC was added and after some mixing, the heating was stopped and the Ti(OEt).sub.4/DEC or Ti(OEt).sub.4/DMC blend was allowed to cool to ambient temperature (about 25° C.) or to 5° C. Then the solid/liquid phase behavior of the cooled blend was monitored over time. As Ti(OEt).sub.4 is sensitive to moisture, all of the experiments were performed under a dry, inert environment. The observations made regarding the solid/liquid phase behavior of the blends over time are shown in Table 1 below.

TABLE-US-00001 TABLE 1 Blend ratio (wt. %) T Observation solid/liquid phase behavior Ti (OEt).sub.4 (° C.) 6 hours 12 hours 24 hours 1 week DEC 100 0 25 Hazy Solid Solid Solid liquid 97.0 3.0 25 Clear Clear Clear Clear liquid liquid liquid liquid 95.6 4.4 25 Clear Clear Clear Clear liquid liquid liquid liquid 92.0 8.0 5 Clear Clear Clear Clear liquid liquid liquid liquid 90.0 10.0 5 Clear Clear Clear Clear liquid liquid liquid liquid DMC 90.0 10.0 5 Clear Clear Clear Clear liquid liquid liquid liquid

[0054] From Table 1, it surprisingly appears that by adding only 3 wt. % of DEC to Ti(OEt).sub.4, the resulting blend remains a homogeneous liquid in the standard state (at 25° C. and 100 kPa). Furthermore, it surprisingly appears that by adding more DEC, the melting temperature of Ti(OEt).sub.4 can even be further lowered. For example, if only 8 wt. % of DEC is added to Ti(OEt).sub.4, the resulting blend also remains a homogeneous liquid at the lower temperature of 5 OC.

[0055] A similar effect for DMC is shown. If only 10 wt. % of DMC is added to Ti(OEt).sub.4, the resulting blend also remains a homogeneous liquid at 5° C.

[0056] The above-mentioned positive effect of DEC and DMC has also been shown for blends of DEC or DMC with Ti(OPr).sub.4, which has a melting point of 17° C., applying the same experimental procedure as described above for the Ti(OEt).sub.4 containing blends. The results for the Ti(O.sup.iPr).sub.4 containing blends are shown in Table 2 below.

TABLE-US-00002 TABLE 2 Observation solid/ Blend ratio (wt. %) T liquid phase behavior Ti (O.sup.iPr).sub.4 DEC or DMC (° C.) 6 hours 1 week 100 0 25 Clear liquid Clear liquid 100 0 17 Hazy liquid Solid 95.0 5.0 5 Clear liquid Clear liquid 92.0 8.0 0 Clear liquid Clear liquid

[0057] From Table 2, it also surprisingly appears that by adding only 5 wt. % of DEC or DMC to Ti(O.sup.iPr).sub.4, the resulting blend also remains a homogeneous liquid at a temperature as low as 5° C. Furthermore, it surprisingly appears that by adding more DEC or DMC, the melting temperature of Ti(O.sup.iPr).sub.4 can even be further lowered. For example, if only 8 wt. % of DEC or DMC is added to Ti(O.sup.iPr).sub.4, the resulting blend also remains a homogeneous liquid at the lower temperature of 0 OC.

[0058] Apart from the above surprising advantages, the addition of DEC or DMC to Ti(OEt).sub.4 or Ti(O.sup.iPr).sub.4 poses no problem in case the resulting catalyst composition is to be used in a chemical production process wherein for example a diaryl carbonate is prepared from DEC or DMC and phenol. By adding DEC or DMC to the Ti(OEt).sub.4 or Ti(O.sup.iPr).sub.4, advantageously no new chemical would be introduced since DEC or DMC is already a starting material in that chemical production process.