DD219488A1 - PROCESS FOR THE PREPARATION OF OXALATE BY REDUCTIVE COUPLING OF CARBON DIOXIDE ACTIVATED TO TRANSITION METAL - Google Patents

Abstract

The invention relates to a process for the preparation of Titanoxalatverbindungen that arise under the action of CO2 on Zweikerntitanorganoverbindungen. The aim of the present invention is to trigger the activation of the kinetically inert and thermodynamically stable CO 2 with the aid of organo-organic compounds and to realize the reductive coupling of the CO 2 under C-C bond to form oxalate compounds. The object underlying the invention is achieved in that bis-cyclopentadienyl-titanium-III-binuclear complexes whose bridge is realized by a ditertiaeres aliphatic diamine, are reacted with CO2 at room temperature and (CO2) atmospheric pressure.

Description

Title of Invention

 Process for the preparation of oxalate by reductive coupling. of carbon dioxide activated at the transition metal

Field of application of the invention. -

The invention relates to a process for the preparation of Osral at verb in dun conditions, the oxalate anion contained by reductive coupling of the C ^ -Bausteins CQ ^ under C-C bond formation on the transition metal titanium is formed.

Characteristic of the Known Technical Solutions It is known that carbon dioxide can be activated at transition metal centers and can participate in these coupling reactions with other substrates.

^; So z. For example, the co-oligomerization of butadiene with * COp on Pd (0) / phosphine catalysts to tetrahydropyrones and open

"Chained Acids and Esters (Musco, A.J. Chem. Soc. Perk.

Trans. I 1980, 693). With Allen, and C0 _? is obtained under cooligomerization using Pd (0) / diphosphine catalysts unsaturated esters (Jolly, PW Tetrahedron letters 21, (1980), 3021).

The oxidative coupling of CO ₂ with dienes to Ni (O) species leads to unsaturated C ₁ -C carboxylic acids and their derivatives (Walther, D. Z. Chem. 22, (1982), 228). DD-WP 239 852/7). The coupling of compounds containing> C = 0 functions under CC linkage succeeded in model substances for

, co ₂ ·: ,, V ''

Floriani was able to link numerous substituted ketones and the COp isoelectronic ketodiimines reductively with C-C bond formation on the transition metal titanium of the oxidation state +2 (Floriani, C. Pure and Appl. Chea. 55 (1) 1983,1) j,

1 9 fi

Object of the invention

The aim of the present invention is to develop a process for the reductive coupling of transition metal titanium activated CO ₂ to Qxalverbindungen.

Explanation of the essence of the invention

The invention has for its object to activate CO ₂ as important for the synthesis of *) building block of isolated titanium III organo compounds, so that under CC bond formation takes place a reductive coupling of 2 molecules of CO ₂ to form oxalate.

The object underlying the invention is achieved in that binuclear BiscyclopentadienyltitanClIjO organo, compounds whose bridge is realized by a di-tertiary diamine ^ ₂ Ti (CH ₂ ) ^ N (C ₄ H ₉ ) - (CH ₂ ) 2- (C ₄ H ₉ ) N (CHg) ₃ ^ iR ₂ ~) exposed to COP under mild conditions (room temperature and C0 ~ saturated atmosphere). In addition to a Grignard-analogous egg-shake product (Ti-IY-dicarboxylate) sine oxalate-bridged Iitan III binuclear compound in R ₂ Ti-CpO ₄ -TiR _2. (R s CcHc = CPi. Cc (CHOc) which after removal of the sparingly soluble Titanium-17-dicarboxylate can be isolated from the reaction mixture by work-up in an aqueous medium in solid Iform and can be characterized.

The invention will be explained in more detail by the following examples:.

Example 1: "^.,

Representation (C ₅ HO ₂ Ti - C2O ₄ -TI- (CCBL) ₂ In 150 ml of benzene, 20 mmöl (C ₅ Hc) ₂ Ti (CH ₂₎ ^ (C ₄ Hq) - (CH _{2) 2} - ( C ₄ H ₉ ) N (CH ₂ ) ₃ Ti (C ₅ H ₅ ) ₂ CO _{2 is} introduced at 10 ^° C. It is possible to isolate the titanium IT dicarboxylate in the form of dark blue crystals after a reaction time of 20 minutes ,

From the remaining solution, the benzene is completely removed and the residue taken up in 70 ml of THF. The THF solution is filtered and the filtrate is mixed with 15-20 ml of oxygen-free water until no water is added

further precipitation can be seen.

The flaky precipitate is filtered, dried in vacuo at 100 ° C and taken up again in THE / Bther (2: Λ ). Concentration gives pale violet crystals of '' -.

CppTi-CpO.-TiCpp with a magnetic moment of i, 71 B.M. Yield; 63%

Example 2;

20 mmole (C ₅ Me _{5) 2} Ti (CH 2) ₃ N (C ₄ H ₉₎ - (CH _{2) 2} - (C ^ H _g) N (CH _{2) 3} Ti (C ₅ IAEE _{5) 2}

are treated with CO "as described in Example 1.

· -,<- '  '".

After 20 minutes, the blue precipitate of the xitan-rv-dicarboxylate is filtered off.

The further workup - as described in Example 1 gives pale violet paramagnetic crystals Q ^ ff -1 * 68 BM) of (Ο ₅ Μθ ₅ ) ₂ Τί-Ο ₂ Ο ^ -α? Ί (ΟεΜθ ^) 2 i ° a yield of

Claims (2)

invention claims 1. A process for the preparation of Titanoxalatverbindungen, characterized in that on exposure to COp on Titananzwaikernverbindungen of the type R ₂ Ti (CH ₂ ) ^ KR '- (CH ₂ ) ₂ -im' (CH ₂ ) ο TiR ₂ (R 'SC ₁ -H ₁ - * Cc (CH -), -; R ¹ = aliphatic, cycloaliphatic radicals having 1-10 C atoms or aromatic radicals; η = 2.3) containing titanium in the oxidation state f3 and its bridge. a ditertiary aliphatic diamine fixed to the titanium by two S "-metal-carbon bonds, CO _{2 is} coupled reductively to oxalate anions by oxidation of the T-itane, 2. The method according to claim 1, characterized in that the resulting oxalate can be identified as RJIi-CpO ^ -TiR- in Porm isolatable crystals.