Patent GB-757463-A (GB)
Title: Process for the extraction of mannitol from seaweed
IPC: C08B37/12
Filed: 1954-09-01
Abstract: Mannitol is extracted from seaweed by dialysis of the juices extracted from the whole weed, or, alternatively, by dialysis of the juices during their extraction from the weeds using the membranes of the latter to effect the dialysis.  The weed is steeped in fresh or slightly acidulated water and withdrawn as soon as the greater part of the mannitol and other crystalloid substances have passed into the water.  Magnesium and calcium salts are then precipitated by adding an alkaline carbonate or an alkaline or alkaline-earth hydroxide. After filtering off the calcium and magnesium salts the ratio of the weight of mannitol to the total weight of alkaline chlorides in the solution is determined, and if the weights are approximately equal the liquid is evaporated and the mannitol separated by crystallization.  If the weight of mannitol is less than that of the alkaline chlorides then pure mannitol is added to obtain equal weights, and the original and added mannitol extracted by crystallization.  After separation of the mannitol salts rich in potassium chloride are obtained by precipitating with dipicrylamine, and iodine extracted from the remaining liquor by precipitating cuprous iodide by adding a copper salt solution and a reducing agent. The remaining liquid may be processed again for recovery of any residual mannitol.  From the juice retained by the dialysing membranes laminarine is precipitated by adding alcohol, acetone, dioxane, or other solvent miscible with water, or by adding a lead salt. Fucoidin and possibly vitamins and antibiotic substances may also be obtained from this juice.  The dialysis may, alternatively, be effected by means of parchment paper, fine cloth, or other membrane.ALSO:Mannitol is extracted from seaweed by dialysis of the juices extracted from the whole weed, or, alternatively, by dialysis of the juices during their extraction from the weeds using the membranes after latter to effect the dialysis.  The weed is steeped in fresh or slightly acidulated water and withdrawn as soon as the greater part of the mannitol and other crystalloid substances have passed into the water.  Magnesium and calcium salts are then precipitated by adding an alkaline carbonate or an alkaline or alkaline-earth hydroxide.  After filtering off the calcium and magnesium salts the ratio of the weight of mannitol to the total weight of alkaline chlorides in the solution is determined, and if the weights are approximately equal the liquid is evaporated and the mannitol separated by crystallization.  If the weight of mannitol is less than of the alkaline chlorides then pure mannitol is added to obtain equal weights, and the original and added mannitol extracted by crystallization.  After separation of the mannitol salts rich in potassium chloride are obtained by precipitating with dipicrylamine, and iodine extracted from the remaining liquor by precipitating cuprous iodide by adding a copper salt solution and a reducing agent. The remaining liquid may be processed again for recovery of any residual mannitol. Laminerine is precipitated from the juice retained by the dialysing membranes by adding alcohol, acetone, dioxane, or other solvent miscible with water, or by adding a lead salt. Fucoidin and possibly vitamins and antibiotic substances may also be obtained from this juice.  The dialysis may alternatively, be effected by means of parchment paper, fine cloth, or other membrane.