Borol solution

NaBH4 3.4NaOH) + 5.6NaOH + 9S02 (Borol Solution)... 

Economic Aspects. U.S. capacity for production of merchant sodium dithionite (soHds basis) was estimated at 93,000 metric tons in 1994. There are three North American producers of sodium dithionite. Hoechst Celanese is the largest producer (68,000 tons capacity) with two formate production locations and one zinc process location. Olin (25,000 t capacity) produces solution product only at two locations using both the amalgam and electrochemical processes. In 1994, Vulcan started a small solution plant in Wisconsin using the Olin electrochemical process. In addition, it is estimated that 13,000 t/yr is produced at U.S. pulp mills using the Borol process from sulfur dioxide and sodium borohydride. Growth is estimated at 2—3%/yr. The... 

Of enormous interest to our present discussion would be XRD data on monomeric boroles in order to determine the structural consequences of 7r-electron delocalization in this four-electron, formally antiaromatic system.30 However, many attempts to grow suitable crystals of 94 have failed, and prolonged storage of solutions has produced only yellow dimers, presumably similar in structure to 100. Hence, in estimating the relative importance of structures 94a-c, spectral data must be our guide. 

Photolysis (see Photochemistry of Transition Metal Complexes) of a mixture of CpRh(C2H4)2 and hexamethylbenzene in hexane solution forms a mixture of (183) and (184). Analogs are similarly formed with biphenyl under the same conditions. The tetrameric borole complex [Rh(/u-3-I)( -C4H4BPh)]4 is converted to [( ] -C4H4BPh)Rh(MeCN)3]BF4 by halide abstraction with AgBF4. The acetonitrile can be... 

Recent research on the chemistry of the boracyclopentadiene or borole system has brought to light further manifestations of such allylic shifts and some novel consequences. Since previous reports on the properties of boroles have proved to be erroneous (4), some comments on their successful synthesis and unusual properties are in order (36). Treatment of 1,4-dilithiotetraphenylbutadiene with phenylboron dihalide in ethyl ether solution will lead to pentaphenylborole as a pale yellow ethyl etherate (S) [Eq. (10)] the ether can be removed under reduced pressure to yield the deep blue-green uncomplexed borole [7 in Eq. 

Spectral maxima measured on solutions of the boroles, which resulted from the interaction of the stannole and E—BX,. 

The dipotassium adduct (9) was prepared from potassium metal and pentaphenylborole (5) in THF solution, as a dark red solid in 91 /o yield. Since siloles (12) also form dimetallo adducts readily (Equation (2)), the independent reaction of pyridine and 4-(dimethylamino)pyridine complexes of (5) with potassium metal to give the dipotassium adduct (9) confirms the participation of the boron 2/jj-orbital in the reaction (Scheme 2). The absence of pyridine from the dipotassium adduct (9) proves that the anionic charge in the borole displaces the coordinated pyridine in order to utilize the 2p -orbital on boron. 

The oxidizing action of 30% H2O2 in aqueous NaOH solution on borole (5) depends upon which reagent is added first. When H2O2 was added to (5) before introducing the base, oxidation of both... 

Sodium hyposulfite (5-7% Na2S204) also is produced on-site at pulp and paper mills by reduction of SO2 with sodium borohydride solution under alkaline conditions (Borol process) ... 

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