Convert word documents to pdf (file size 200 mb)

I am using interop code:-

 

 

doc = msWordDoc.Documents.Open(ref originalDocPath, ref oMissing, true,
ref oMissing, ref oMissing, ref oMissing, ref oMissing,
ref oMissing, ref oMissing, ref oMissing, ref oMissing, ref oMissing,
ref oMissing, ref oMissing, ref oMissing, ref oMissing);
// msWordDoc.Documents.Close(ref oMissing, ref oMissing, ref oMissing);
if (doc != null)
{
doc.Activate();
object fileFormat = WdSaveFormat.wdFormatPDF;
//doc.ExportAsFixedFormat((string)originalDocPath, WdExportFormat.wdExportFormatPDF);
doc.SaveAs(ref pdfPath,
ref fileFormat, ref oMissing, ref oMissing,
ref oMissing, ref oMissing, ref oMissing, ref oMissing,
ref oMissing, ref oMissing, ref oMissing, ref oMissing,
ref oMissing, ref oMissing, ref oMissing, ref oMissing);

 

but this code has restricted me for 88 mb doc file.